THE MEDICAL
COLLEGE OF
WISCONSIN
THE EFFECT OF CARBON MONOXIDE
ON TIME PERCEPTION
REPORT NO: CRC APRAC CAPM - 3 - 68MCOW - ENVM - CO - 72 - 2
-------
THE EFFECT OF CARBON MONOXIDE ON
TIME PERCEPTION
By
Richard D. Stewart, M. D. , M. P. H.
Paul E. Newton, M.S.
Michael J. Hosko, Ph. D.
Jack E. Peterson, Ph. D.
REPORT NO. : CRC APRAC CAPM-3-68 MCOW-ENVM-CO-72-2
From the Department of Environmental Medicine, The Medical College of
Wisconsin, 8700 West Wisconsin Avenue, Milwaukee, Wisconsin, 53226.
Supported by Contract CRC-APRAC, Project No. CAPM-3-68, from the
Coordinating Research Council, Inc. , and the Environmental Protection
Agency.
-------
SYNOPSIS - ABSTRACT
Twenty-seven healthy, adult male and female volunteers were exposed
to carbon monoxide at concentrations of < 2, 50, 100, 200 and 500 ppm for
periods up to 4^ hours for the purpose of determining the effect of the gas
upon time perception. These exposures, which resulted in a range of carboxy-
hemoglobin saturations up to 20%, produced no impairment in the ability of the
subjects to perform the Beard-Wertheim Time Discrimination Test, to esti-
mate ten or thirty second intervals, or to perform the Marquette Time Esti-
mation Test.
-------
The first untoward effect of carbon monoxide (CO) upon healthy man is
reported to be a gross impairment in his ability to distinguish between short
intervals of time and to estimate 30-second intervals ' . Alarmingly,
these decrements in time perception are reported to be produced by exposures
to CO at concentrations as low as 50 parts per million (ppm) for 90 minutes,
(3)
exposures which are currently acceptable in American industry , commonly
(4 5)
encountered by urban populations v ' , and much lower than those experi-
enced by the average adult smoking one pack of cigarettes per day
The implications of these CO induced decrements were judged to be of
such critical importance that two independent research groups conducted
similar, though not identical, time perception experiments in an attempt to
corroborate the observations of the original investigators, Beard and
(7 8 9)
Wertheim. Neither independent research group was able to do so ' .
Meanwhile, major review articles dealing with the toxic effects of CO upon
man listed the time perception impairment as an early untoward effect of CO
exposure *5' ' ' '. The issue became more confused when Dr. Beard
announced that he was unable to reproduce his original findings .
In an effort to gain additional information as to the precise effect- of CO
upon human time perception, a comprehensive investigation was undertaken
which included a series of time tests performed under conditions identical to
those reported by Beard and Wertheim in their original work. This investi-
gation is the subject of this report.
-------
-2-
EXPERIMENTAL METHOD
The performance of these time perception studies required that healthy
volunteers be exposed to CO. This was done with strict adherence to the eth-
ical and technical requirements for human inhalation experimentation previ-
(14)
ously detailed
Exposure Chamber:
The CO exposures were carried out in the controlled environmental
chamber located at the Department of Environmental Medicine, The Medical
College of Wisconsin . The chamber, a room measuring 20 x 20 x 8 feet,
provided accurate control of temperature (72 _ 2 ° F) and relative humidity
(40 t 5% RH) for all exposures. This chamber featured pleasant lighting,
comfortable chairs, study tables, a restroom facility and an audiometric
booth (Industrial Acoustics Co. , Model 401). The subjects were under con-
tinuous visual surveillance by medical personnel while in the chamber and, in
addition, their activities were visually monitored and periodically video taped
by closed circuit television.
Exposure Chamber Atmosphere:
Carbon monoxide was continuously metered into the chamber's incom-
ing air supply from a compressed gas cylinder in the adjacent command
laboratory. The CO used was a chemically pure grade with a minimum purity
of 99. 5%.
-------
-3-
Chamber CO concentration gradients when operating at 100 ppm and
with subjects stationary, were found to be less than 2 ppm, except inside of
the restroom facility and immediately in front of the entrance door where the
concentration was lower by 3 - 5 ppm. Studies showed the audiometric booth's
circulation fan kept the interior of the booth at the chamber concentration.
The concentration of CO in the chamber atmosphere was continuously
recorded by an infrared spectrophotometer equipped with a 10-meter path-
length gas cell which was continuously flushed with air drawn from the cham-
ber through £" diameter polyethylene tubing. A MSA CO meter and alarm,
Model 701, provided a second independent means of continuously monitoring
chamber concentration. The chamber atmosphere was also sequentially
sampled by a gas chromatograph (GC) equipped with a helium ionization
detector.
All three independent methods of monitoring CO concentration during
an exposure were calibrated from within the chamber with a series of standards
prepared in 30-liter saran bags. Prior to each exposure and every hour dur-
ing each chamber exposure the series of CO standards was run.
Subjects:
During the period from February 1970 to August 1971, 27 healthy
graduate students and Medical School faculty, 23 males and 4 females, ranging
in age from 22 to 43 years, served as volunteer subjects for the exposure
studies. Three of the subjects were smokers, and they agreed to abstain from
-------
-4-
smoking for the duration of the study; pre-exposure carboxyhemoglobin (COHb)
attested to this agreement. Prior to and after completion of the study, each
subject was given a comprehensive medical examination, which included a
complete history and physical examination, a 12-lead EKG and a standard
EEC.
Carboxyhemoglobin Determination:
Venous blood samples for COHb determination were obtained from
each subject 30 minutes prior to exposure and evey hour during exposure so
that time perception test results could be correlated to blood COHb satura-
tions. At the time of blood sampling a subject would stick his arm through
an arm-port in the chamber wall into the adjacent laboratory so that the veni-
puncture could be performed in an uncontaminated atmosphere.
Five milliliter aliquots of venous blood were collected in Vacutainer
tubes containing ethylenediaminetetraacetic acid. The blood was immediately
(4f 7)
analyzed by two methods ' . The first method determined the hemoglobin
concentration and the COHb percentage directly using a CO-Oximeter (Instru-
mentation Laboratories, Inc. ). The second analytical method consisted of
measuring the CO liberated from the COHb moiety, using the gas chromato-
graph equipped with a helium ionization detector.
Testing Procedure:
The study consisted of double-blind exposures conducted in a random
order to < 2, 50, 100, 200 and 500 ppm CO for periods of time up to 4| hours.
-------
-5-
Exposures were designed so that the maximum COHb saturation reached would
not exceed 20%. A chronological listing of these exposures along with the
mean and standard deviation of the CO concentration for each is presented in
Table I.
Three tests of time perception were used in this study. The time dis-
crimination test along with the 10- and 30-second estimations were the two
tests originally administered by Beard and Wertheim to subjects isolated in
(1 2)
an audiometric booth ' '. The third test, the Marquette Time Estimation
Test, was previously administered by Stewart, et al, to subjects in a group
setting to evaluate the effect of CO upon time sense . The tests were
administered each hour during exposure in the following order: 10- and 30-
second estimation, the Marquette Time Estimation Test, and the Beard-
Wertheim Time Discrimination Test. The complete protocol used is printed
in the first CRC report(15).
In order to investigate the difference resulting from testing conducted
in an isolated or group setting, nine subjects were tested in an audiometric
booth, isolated in the environmental chamber, and in a group setting in the
environmental chamber. When the time perception tests were performed in
a group setting, each subject was seated in a chair equally spaced along one
side of a table spanning two sides of the chamber. Each performed his test in
absolute silence while looking straight ahead.
The subjects were arbitrarily divided into five groups for testing pur-
poses. Prior to commencing the study, each group of subjects had one
-------
-6-
training session. During this session the subjects were seated in the expo-
sure chamber and given the series of tests in the exact order and with the
same instructions as they would be given during an actual exposure. Pre-
vious experience with the battery of time tests indicated that there was no
learning effect once the subject became familiar with the mechanics of testing.
The "learning" curves for the five groups affirm the validity of this prior
observation
Marquette Time Estimation Test:
A detailed description of this test has been presented previously^ ' '
It consisted of a series of nine tone stimuli followed by a series of nine light
stimuli, the duration of each of which the subject was required to estimate.
Each series contained stimuli of approximately 1, 3, or 5 seconds duration,
which were presented in a random order with three stimuli at each time
interval. At termination of the stimulus, the subject immediately depressed
a push-button switch for that interval of time he estimated to be equal in
duration to the original auditory or light stimulus. This provided a measure-
ment of his reaction tirr e and of his ability to estimate the duration of the
stimulus. It required seven minutes to perform this test.
Ten and Thirty Second Time Estimation:
To perform these time estimation tests, each subject depressed the
pushbutton described above for an interval he estimated to be 10 seconds;
-------
-7-
this was repeated twice. The 30-second estimation test was performed in the
same way and \vas repeated twice.
Beard-Wertheim Time Discrimination Test:
The time discrimination test was designed to test a subject's ability to
discriminate differences in duration of two short intervals of time. The test
was composed of three sequences with 30 seconds rest between each sequence.
Each sequence consisted of 25 pairs of tones as described by Beard and
Wertheim^ ' '. The first tone was always one second in duration and was fol-
lowed 1. 5 seconds later by a randomly selected second tone of identical,
slightly longer or slightly shorter duration. The duration of the second tone
for each sequence is listed in Table II.
Listening through his individual earphone to the taped sequence
(Precision Instruments Model 6100 tape recorder), the subject decided at ter-
mination of the second tone whether it was the same, longer, or shorter than
the duration of the first tone. He signaled his response by depressing one of
three push-button switches on a mini-box which were labeled "longer, "
"same," and "shorter. "
The set of three test sequences (75 pairs of tones) took approximately
15 minutes to perform.
Data Analysis:
Group F and t-tests were performed to compare baseline time per-
ception data ( < 2 ppm CO) to performance data collected during exposure
-------
-8-
( > 2 ppm CO). Then paired t-tests were used to search for individual
responses to CO exposure. To further investigate the difference between the
means of the baseline and exposure data, 95% confidence limits of this dif-
ference were calculated. Regression analysis of the test scores with COHb
saturations were also done.
In an attempt to minimize the effect of spurious data, the score of any
test less than or greater than the mean _ 3 standard deviations was considered
to be spurious and eliminated from further data analysis. The data elimi-
nated and the corresponding COHb saturations can be found in Appendix F of
reference 15. It can be seen that these extreme values were random and not
a function of COHb saturation.
For the time discrimination test, the number of correct responses in
each sequence of 25 stimuli along with the associated COHb saturation com-
posed the bivariate sample population. For the 10- and 30-second time esti-
mations, each estimate and the associated COHb saturation composed the
bivariate sample population. And for the Marquette Time Estimation Test,
each response for a stimuli with its associated COHb saturation composed the
bivariate sample population.
RESULTS
All of the data which were collected during this investigation are
available for review in reference 15. The space limitations of this report
-------
-9-
only allows the inclusion of those data most pertinent to the discussion.
The Effect of CO on the Beard-Wertheim Time Discrimination Test:
The ability of the subjects to perform this time perception test at
various COHb saturations in the three test settings is summarized in Tables
III, IV, V and VI. A group F test and t-test showed that the ability to per-
form this test in the three settings was not altered by CO exposures resulting
in COHb saturations ranging from 0. 4% to 20%. Regression analysis yielded
maximum correlation coefficients of -0. 51, -0. 097, and 0. 308 for the group,
the isolated, and the booth settings, respectively.
Should an elevated COHb be responsible for a minute decrement in
time discrimination not detected by the statistical methods employed, the
absolute value of the difference in group means for the number of correct
responses for each sequence of 25 stirruli can be calculated with 95% confi-
dence to be less than .44 (1. 8%), 1. 50 (6. 8%), and 1. 05 (4. 3%) for the group,
isolated and booth settings, respectively.
A paired t-test was employed to compare each subject's mean base-
line score with his mean score following CO exposure (Table VII). For the
group and isolated settings there was no significant difference. In the booth
setting, however, seven of the nine subjects had "statistical" decrements
in their performance when exposed to CO with an average decrement of 0. 74
out of 25 (2. 9%), significant at the 95% confidence level. This decrement of
2. 9% in test performance was produced by a mean COHb saturation of 9. 74%.
-------
-10-
The Effect of CO on 10-Second Estimations:
The effect of CO exposure upon the ability to estimate 10 seconds in
the three test settings is presented in Table VIII which shows that no correla-
tion exists between the ability to estimate 10 seconds and COHb saturations
ranging from 0. 4 - 20%. Regression analyses of the 10-second estimations
showed a maximum correlation coefficient of -0. 116, 0. 229, and 0. 190 for
the group, isolated, and booth settings, respectively.
Comparison of the group and the individual baseline performance data
versus performance data following CO exposure show no significant differ-
ences (Tables IV, V, VI and VII). The 95% confidence limits of the difference
between the means of the estimation made by the non-exposed versus the
exposed subjects, should it exist, is a maximum of 0. 27 seconds (2. 7%), 1. 2
seconds (12%), and 0. 67 seconds (6.7%) for the group, isolated, and booth
settings, respectively.
The Effect of CO on 30-Second Estimations:
The effect of CO exposure upon the ability to estimate 30 seconds in
the three test settings is presented in Table IX, which shows that no correla-
tion exists between the ability to estimate 30 seconds and COHb saturations
ranging from 0. 4 - 20%. Regression analyses of the 30-second estimations
showed a maximum correlation coefficient of 0. 096, 0. 20, and 0. 31 for the
group, isolated, and booth settings, respectively.
-------
-11-
Comparison of the group baseline performance data versus perfor-
mance following CO exposure (Tables IV, V, VI) did show a significant differ-
ence in the isolated setting while comparison of individual performance data
(Table VII) failed to show a significant difference. The 95% confidence limits
of the difference between the group means, should it exist, is a maximum of
0. 58 seconds (1. 9%), 4. 06 seconds (13. 3%), and 2. 21 seconds (7. 3%) for the
group, isolated, and booth settings, respectively. These limits were inclu-
sive of zero except for the alone setting •which missed including zero by 0. 37
seconds (1. 2%).
The Effect of CO on the Marquette Time Estimation Test:
Three values were used to define test performance. The first two,
the ratio of the estimate duration over the stimulus duration (E/S) and the
absolute value of their difference IE-Si , were a measurement of the subject's
ability to estimate the duration of the time stimulus. The third measurement
was the subject's reaction time, that time from the end of the stimulus to the
onset of the subject's response.
I. Estimate/Stimulus (E/S):
The relationships between the variable E/S and COHb saturation
for the three stimulus lengths, two stimulus types and three test settings are
presented in Tables X- XV. These data fail to indicate any relationship
between performance and CO exposure. The maximum correlation coeffi-
cients from regression analysis are 0. 189, 0. 273, and 0. 354 for the group,
isolated, and booth settings, respectively.
-------
-12-
Comparison of the baseline performance data versus exposure data
using a group t-test (Tables XIV - XIX in reference 15) disclosed that the
average E/S following CO exposure was higher (p = . 05) for four of the
eighteen combinations of stimulus durations, stimulus type and test setting.
Analysis of the same data, individual by individual, using a paired t-test
(Table VII), showed no significant difference between baseline performance
and performance following CO exposure.
The 95% confidence limits of the average difference between the base-
line performance and post-exposure performance data means for the three
stimulus durations, two stimulus types and three test settings are presented
in Tables XIV- XIX of reference 15. These limits were inclusive of zero in
all but the four cases mentioned above. The maximum difference from zero
within these limits was 0. 07 (7%).
II. Absolute Value of Estimate-Stimulus ( |E-SI ):
The relationships between the variable ( |E-SI ) and COHb satu-
ration for the three stimulus durations, two stimulus types and three test set-
tings are presented in Tables XX- XXV of reference 15. There are no con-
sistent trends and no relationship between performance and COHb saturation
are evident. The maximum correlation coefficients from regression analysis
are 0. 120, 0. 339, and 0. 559 for the group, isolated and booth settings,
respectively.
Comparison of the baseline performance data versus exposure data
using a group t-test (Tables XXVI- XXXI in reference 15) revealed that the
-------
-13-
average |E-S| following CO exposure was significantly different (p = . 05)
from baseline data in two of the eighteen combinations of stimulus durations,
type and setting. Both of these cases occurred in the isolated setting where
the subjects' time perception appeared to be improved by an elevated COHb
saturation. Comparison of the same data, individual by individual, using a
paired t-test (Table VII), revealed two of the sixteen combinations to be
significantly {p = . 05) different. These were two different combinations than
mentioned above but, again, the subjects appeared to perform better with an
elevated COHb saturation.
The 95% confidence limits on the difference between the means of the
baseline performance data and post-exposure data for the various stimulus
durations, types and test setting are presented in Tables XXVI - XXXI of
reference 15. Only the two tests which 'were significantly different have
limits not inclusive of zero and their maximum difference from zero is 0. 03
(3%).
III. Reaction Time:
The relationships between the subjects' reaction time and COHb
saturation for the three stimulus durations, two stimulus types and three test
settings are presented in Tables XVI- XXI. It is apparent that there are no
consistent trends in the data and that no relationship between reaction time
and COHb saturation are present. The maximum correlation coefficients
from regression analyses are 0.234, 0. 344, and 0.431 for the group,
isolated and booth settings, respectively.
-------
-14-
Comparison of the baseline reaction times versus post-exposure
reaction times using a group t-test (Tables XXXVIII- XLIII in reference 15)
revealed that the average post-exposure reaction time was significantly dif-
ferent from the baseline reaction time in five of the eighteen combinations of
stimulus durations, types and test settings. These differences occurred only
in the group setting where the subjects had shorter reaction times with elevated
COHb saturations. Comparison of the same data, individual by individual,
using a paired t-test (Table VII) revealed no significant difference between
baseline and post-exposure reaction times.
The 95% confidence limits of the difference between the means of the
baseline and the post-exposure reaction times for the various stimulus lengths,
types and test settings are presented in Tables XXXVIII - XLIII of reference
15. Only the five tests which were significantly different do not have limits
inclusive of zero and their maximum difference from zero is 0. 02 seconds.
DISCUSSION OF RESULTS
The results of these time perception studies indicate that the acute
exposure of healthy adults to concentrations of CO up to 500 ppm which result
in COHb saturations as great as 20% has no detrimental effect upon man's
time sense. Thus, the studies corroborate the previously reported investi-
gations of Stewart, et al ', and O'Donnell, et al * ' "'. The findings stand in
obvious and striking disagreement to those reported by Beard and Wertheim ' .
-------
-15-
Beard-Wertheim Time Discrimination Tests:
The magnitude of the difference between the results of the Beard-
Wertheim time discrimination test as performed in the two laboratories is
graphically presented in Figure 1. The Beard-Wertheim data points repre-
sent the mean performance of a group of subjects individually tested in a
single-blind mode in an audiometric booth. The data points from this labora-
tory show the mean performance of the 27 subjects tested in the five group
settings in a double-blind mode. This immediately raises the question as to
whether the observed difference could be significantly influenced by the test
setting in which the investigations were conducted.
To evaluate the influence of interaction between individuals tested in a
group setting upon time discrimination, nine individuals from the five groups
were additionally tested in two isolated test settings: 1) in an audiometric
booth identical in construction to that used by Beard and Wertheim; 2) when
seated alone in the large environmental chamber. The results of this investi-
gation are presented in Table XXII, which shows that there was no significant
difference in the performance of the time discrimination test when admin-
istered in the three test settings.
The next possible reason for differences in test results may be that
the time discrimination test sequences as performed in the two laboratories
were not identical. At the present time there is no way to resolve this poten-
tial difference since the original Beard and Wertheim test tapes and raw data
are no longer available for review. The original investigators neglected to
-------
-16-
record the precise time intervals studied, however, the intervals studied in
this laboratory (Table II) were chosen after consultation with Beard and
Wertheim. Thus, the question as to the equality of the two tests may never
be resolved.
Differences between the test populations could conceivably account for
the differences in test results. Beard's subjects were Stanford University
students who were paid $2. 50 per hour. With the exception of the faculty
members who participated in the study in this laboratory, the subjects were
graduate students at Marquette University who were also paid $2. 50 per hour.
At this juncture there is no way to ascertain whether a significant difference
in motivation existed between the two groups.
The next area which could have contributed to differences in test
results between the two laboratories is that of the known technical differences
in the testing procedure. These differences are listed in Table XXIII and most
likely represent those factors most responsible for the test result differences.
Finally, the failure to statistically evaluate each individual's performance by
itself instead of lumping all data into group means precludes as complete
analysis as is possible.
It was observed that in the group setting the subjects did not perform
each of the three sequences in the Beard-Wertheim test with equal accuracy.
These data are tabulated in Tables XLVI - XLVIII of reference 15. While the
difference induced by the group setting is small, it is another test variable
which could be of importance.
-------
-17-
The test results revealed that no decrement in time discrimination
occurred in subjects with elevated COHb saturation when tested in the isolated
or in the group setting. However, in the booth setting, seven of the nine
subjects had slight decrements in performance as determined by the paired
t-test. This occurred at a mean COHb saturation of 9. 74%. Unfortunately,
the sample size of nine is not large enough to eliminate this as a spurious
observation. Yet, even if this minute decrement were subsequently proved to
occur in the booth test setting, the decrement of 0. 74 correct responses out
of 25 (2. 9%) is still diametrically opposed to the decrement of 44% in test per-
formance at this carboxyhemoglobin saturation which was reported by Beard
and Wertheim.
In conclusion, the fact that two independent research groups utilizing a
double-blind mode were unable to corroborate the gross time discrimination
impairment reported by Beard and Wertheim, and that Dr. Beard himself
could not reproduce his original observations when utilizing a double-blind
mode, support the contention that carboxyhemoglobin saturations ranging
from 0. 4 to 20% have no significant effect on the performance of the time dis-
crimination test.
Ten Second Time Estimation:
The results of this study indicate that a COHb saturation ranging from
0. 4 to 20% has no effect on the ability to estimate a ten-second interval.
These results are in agreement with Beard and Wertheim^ ' ' and O'Donnell,
-------
-18-
(8 9)
et al v ' , who also reported no decrement in performance as a result of CO
exposure.
It was observed, however, that the test setting in which this time esti-
mation was performed did introduce a significant performance variable.
These data are tabulated in Tables XLIX - LII of reference 15. The estimation
of the ten-second interval in the group setting was significantly different than
the estimation of the ten-second interval when in the isolated or in the booth
test setting. This suggests that subject interaction may be responsible.
It is of interest to observe that in the group setting there was a signifi-
cant difference in the estimated duration of each of the three 10-second inter-
vals. Since this was observed in the group setting only, it suggests subject
interaction and may well be explained by the fact that the signal switches were
not completely silent and could be heard by others.
Thirty-Second Time Estimation:
The results of this study indicate that a COHb saturation ranging from
0. 4 to 20% has no detrimental effect on-the ability to estimate 30 seconds.
(8 9)
This is in agreement with O'Donnell, et alv ' ', but is in disagreement with
(1 2)
Beard and Wertheim ' . The magnitude of the reported difference between
the Beard-Wertheim data and that of this laboratory is shown in Figure 2.
As was the case with the 10-second time estimation testing, the test
setting and not the COHb saturation was the significant variable responsible
for the minute differences observed. These data are tabulated in Tables
-------
-19-
LIV - LVI of reference 15. In the group test setting, the reproducibility of the
estimation of one sequence to the next showed a slight but significant difference.
The most likely explanation for this phenomenon is subject interaction in the
group setting. Estimation of 30 seconds in the group and in the isolated
setting did differ significantly from estimation of that time interval in the
booth setting. This indicates that the use of an audiometric booth as a test
chamber may allow the introduction of complex factors most difficult to define
accurately.
Marquette Time Estimation Test:
While the Marquette time estimation test cannot be used to corrobo-
rate or disaffirm the Beard-Wertheim data, it can be used as a valid indi-
cator of an individual's ability to rapidly estimate short intervals of time.
The results of this study completely corroborate the results reported in a
previous study ( and clearly indicate that a COHb saturation ranging from
0. 4 to 20% exerts no adverse effects upon the performance of this test.
There are additional interesting observations which can be made
regarding the test and the performance differences which occurred in different
test settings, performance differences completely unrelated to COHb satura-
tions. Tables LVII - LXII in reference 15 show the influence of the test
setting on the estimate/stimulus ratio. It is of interest to observe that the
estimation of a short sound stimulus was influenced by the test setting while
the estimation of the duration of a short light stimulus was not so influenced.
-------
-20-
The estimation of the sound stimulus in the group setting was significantly
different than when estimated in either the isolated or booth setting.
Tables LXIII - LXVIII in reference 15 reveal that the duration of the
stimulus was a highly significant factor in accurately estimating its length.
The one-second stimuli estimations were minutely, but significantly different
for both sound and light stimuli duration in all three test settings.
Tables LXIX - LXXI in reference 15 reveal that in the group test
setting, the subjects estimated the duration of short sound stimuli differently
than the duration of short light stimuli.
Tables LXXII - LXXVII in reference 15 show the effect of the test
setting upon the estimation of the stimulus as reflected in the variable |E-S| .
In two of the eighteen testing situations, |E-S| was significantly different but
this was not additionally influenced by varying COHb saturations. Tables
LXXVIII - LXXXIII of reference 15 again reflect the influence the duration of
the stimulus had upon the accuracy of the response. The subjects handled the
one-second stimuli significantly differently than the three and five-second
stimuli. Only in the group test setting wh'ere subject interaction could occur
did the type of stimulus presented influence the time estimation.
The subject's reaction time was longer in the group test setting than in
the isolated or in the booth settings for stimuli of all durations and both types
(Tables LXXXIV - LXXXIX in reference 15). The remainder of the tables in
reference 15 show that the subjects' reaction time varied with the duration of
the stimulus. It is apparent that each of the subjects used some method with
-------
-21-
which to count and thereby estimate the duration of the stimulus. When the
stimulus was not approximately one or three seconds, the subject would
anticipate a stimulus of approximately five seconds and be better set to
promptly react.
In conclusion it can be stated that while the Marquette time estimation
test was influenced by multiple variables, it was not influenced by COHb satu-
ration ranging from 0.4- 20%.
SUMMARY
The purpose of this investigation was to study the effect of acute car-
bon monoxide exposure upon time perception with special attention to the
Beard-Wertheim time discrimination test, the ten- and thirty-second time
estimation tests, and the Marquette time estimation test. Twenty-seven
healthy, adult male and female volunteers were exposed to carbon monoxide
at concentrations of < 2, 50, 100, 200 and 500 ppm for periods up to 4^ hours.
The subjects were studied in three test settings: seated in small groups
within the large environmental chamber, seated isolated in a large environ-
mental chamber, and seated in an audiometric booth as had been done by
Beard and Wertheim.
The results of the time perception studies can be summarized as
follows:
-------
-22-
1. The Beard-Wertheim time discrimination test was not affected
by COHb saturations ranging from 0. 4 - 20%. The test setting
did not exert a significant affect upon the performance of this
test.
2. The ability to estimate ten and thirty-second intervals was not
affected by COHb saturations ranging from 0.4 to 20%. In the
group setting, subject interaction did influence the test results.
3. The ability to perform the Marquette time estimation test was
not affected by COHb saturations ranging from 0. 4 to 20%. Time
estimation was influenced by the type of stimulus, stimulus
duration, and the test setting.
These results corroborate the previous studies by Stewart, et al, and
O'Donnell, et al, dealing with the effect of acute CO exposure on time per-
ception. The studies do not corroborate the reported findings of Beard and
Wertheim. It appears that time perception is highly resistant to the effect of
carbon monoxide and is unaffected by exposures which produce obvious toxic
(7)
effects in more sensitive organ systems and in people with advanced
cardiovascular disease
-------
TIME DISCRIMINATION TEST
UJ
-------
30 SECOND TIME ESTIMATE TEST
60J
50J I
o
< 40J f
CO
O
o
£ 2l
o
ro
IOJ
5 Stewart, et a/; mean± 1 standard deviation
$ Beard and Wertheim; mean ± / standard deviation
50 100 150 200 250 300
CO CONCENTRATION PPM
Figure 2
-------
TABLE I
A CHRONOLOGICAL LISTING OF ALL EXPOSURES
Experiment
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
Subjects
8
8
8
8
8
7
6
7
8
6
8
6
6
6
6
6
4
2
1
2
2
2
6
2
2
2
6
2
2
2
5
5
6
1
2
CO Concentration,
Mean S. D.
100.99
50. 64
196.49
< 2
49. 82
201.38
< 2
99. 81
96. 13
203. 69
< 2
< 2
49.45
201. 70
< 2
49. 67
99.93
201. 72
192.90
< 2
< 2
< 2
< 2
193. 10
197. 70
< 2
192. 30
199.96
< 2
< 2
190. 00
196. 98
< 2
<2
< 2
4.28
3. 83
3.00
- -
2.36
6. 58
- -
3.77
4. 39
6.39
- -
- -
1.43
4.21
- -
3. 56
1.66
6. 94
5. 85
- -
_ _
- -
- -
13.40
9. 56
t ^ _
21.40
2.97
- -
- -
17. 50
8.66
- -
_ _
- -
ppm
S.E.
0. 54
0. 54
0.41
- -
0,31
0. 95
- -
0. 77
0.62
1.33
- -
- -
0.27
0. 72
- -
0.66
0.31
1.36
1. 15
- -
- -
- -
- -
2.60
1.69
- -
3. 50
0. 56
- -
- -
2. 50
1.69
- -
- -
- -
Duration
(hr)
5. 0
5. 0
5. 0
5. 0
5. 0
5. 0
5.0
2. 5
5. 0
2. 5
5. 0
2. 5
2. 5
2. 5
2. 5
2. 5
2. 5
2. 5
2. 5
2. 5
2. 5
2. 5
5. 0
2. 5
2. 5
2. 5
5.0
2. 5
2. 5
2. 5
2. 5
5.0
5. 0
2.5
2. 5
-------
Table I, continued
36
37
38
39
40
41
42
43
44
45
46
47
48
49
1
7
7
7
7
6
7
7
6
6
7
8
8
8
< 2
198. 61
< 2
210. 08
199.21
< 2
< 2
197.80
2.87
< 2
197.48
203.40
507. 00
/500 p|
- -
6.47
_ _
13.66
10. 12
- -
_ _
6.06
0.99
_ _
6.49
10. 12
9.06
Dm for 75
- -
0.55
- -
1.17
0.87
- -
_ _
0. 53
0. 86
_ _
0. 55
0. 81
1.49
minutes,
2. 5
5.0
5. 0
5.0
5.0
5.0
5.0
5.0
5.0
5. 0
5.0
5. 0
LlOO ppm for 140 minutes
50 8 <2 - - - - 5.0
-------
TABLE II
The Beard-Wertheim test was composed of three sequences with a few
seconds rest between each sequence. Each sequence was composed of twenty-
five pairs of tones. The first tone was always one second in duration, and
was followed 0. 5 seconds later by a second tone of identical, slightly longer
or slightly shorter duration. The length of the second tone for each pair was
as follows:
Sequence I
1240 msec.
1080
880
1000
760
S40
1000
1200
1320
640
1000
680
960
1000
800
720
1120
1040
920
1160
1280
1000
1000
1000
1000
Sequence II
880 msec.
840
640
1200
1320
1000
1280
1080
1000
800
1000
680
720
960
1000
920
1000
1240
1000
1120
1040
1000
1160
1000
760
Sequence III
11 60 msec.
1000
1000
1120
1000
800
1000
720
920
1040
960
640
J240
1080
1200
680
1000
760
880
1000
1000
1320
1280
840
1000
-------
TABLE III
RELATIONSHIP BETWEEN PERFORMANCE
OF THE BEARD-WERTHEIM TIME DISCRIMINATION TEST
AND CAREOXYHEMOGLOBIN SATURATION
Situation
Group
Alone
Booth
Baseline
Data
17.73+2.26
N = 395
17.67+2.72
N = 42
18.02+2.39
N = 59
•
0 - 2
17.67+2.52
N = 18
N = 0
N = 0
PERCENT CARBOXYHEMOGLOBIN LEVEL
EXPOSURE DATA
2.01-4 4.01-8 8.01-12 12.01-16 16.01-20
17.66+1.97
N = 111
N = 0
N = 0
17.55+2.25
N = 212
17.83+2. 12
N = 12
6.33+3.51
N = 3
17.77+2.27
N = 185
18.00+2.65
N = 15
18.38 + 1.75
N = 21
17.23+2.37
N = 166
N = 0
16.67+1.53
N = 3
17. 56+2.26
N = 114
N = 0
N = 0
••••zmBntHHSMDc1
0-20
17.55+2.2:
N = 806
17. 92+2. 38
N = 27
17.96+2.03
N = 27
'" Mean - 1 Standard Deviation
-------
TABLE IV
COMPARISON OF BASELINE AND EXPOSURE DATA FOR THE
10 AND 30 SECOND ESTIMATIONS AND THE BEARD-WERTHEIM TEST
GROU'P
SITUATION
10 Second
Estimations
30 Second
Estimations
Beard
Test
Baseline
Data
#*
9.85+1.53
N = 591
30.44±4.29
N = 576
17. 73+2. 26
N = 395
Exposure
Data
9.98 + 1.41
N = 1194
30.58t4.27
N = 1175
17. 55+2.25
N = 806
F and t
Te.;l
Values
F = 1.085
t = 1.782
F = 1.005
t = 0. 644
F = 1.004
t = 1.301
95% Confidence
Limits of D>'
-0. 016^D^O. 278
-0.283
-------
TABLE V
COMPARISON OF BASELINE AND EXPOSURE DATA FOR THE
10 AND 30 SECOND ESTIMATIONS AND THE BEARD-WERTHEIM TEST
ALONE
SITUATION
10 Second
Estimations
30 Second
Estimations
Beard
Test
Baseline
Data
10. 07+1. 8<
N = 57
30.38+4.08
N = 52
17.67+2.73
N = 42
Exposure
Data
10. 48+2. 15
N = 46
32.60^5.03
N = 46
17.92+2.38
N = 27
F and t
Test
Values
F = 1.138
t = 1.029
F = 1.236
t = 2.413
F = 1. 147
t = 0.390
95% Confidence
Limits of D*
-0.393£D_fl.205
+0.369fD<4. 061
-0.982
-------
TABLE VI
COMPARISON OF BASELINE AND EXPOSURE DATA FOR THE
10 AND 30 SECOND ESTIMATIONS AND THE REARD-WERTHEIM TEST
BOOTH
SITUATION
10 Second
Estimations
30 Second
Estimations
Beard
Test
Baseline
Data
*#
10.36ll.56
N = 84
32.02+3.63
N = 83
18. 02+2.39
N = 59
Exposure
Data
10.42 + 1.84
N = 50
32.83+4.17
N = 51
17.96+2.03
N = 27
F and t
Test
Values
F = 1. 180
t = 0.201
F = 1.149
t- I. 185
F = 1.177
t = 0.113
95% Confidence
Limits of D*
-0. 556
-------
PAIRED
TABLE
"t" VALUES FOR TIME
VII
DISCRIMINATION TESTS
.. TEST
GROUP
SITUATION
H^jquette Test
One
Second
Sound
Three
Second
Sound
Five
Second
Sound
. .
One
Second
Light
Three
Second
Light
Five
Second
Light
E/S
E-S
RxT
E/S
E-S
RxT
E/S
E-S
RxT
E/S
E-S
RxT
E/S
E-S
RxT
E/S
E-S
RxT
*-V Second Estimation
30 Second Estimation
B«ard Test
t df
-1.59 26
-0.06 26
0.54 26
1.23 26
-0.45 26
0.66 26
0.92 26
-0.03 26
0.30 25
-0.25 26
1.16 26
0.35 26
-0.96 26
1.94 26
0.85 26
0.81 26
0.06 26
0.88 26
=========
0.20 26
-0.93 26
0.66 23
ALONE BOOTH
SITUATION SITUATION
t dj
-0.48 4
0.16 4
2.40 4
0. 13 4
2.70 4
1.00 4
0. 54 4
0.90 4
1.26 4
-0.34 4
3.87* 4
1.48 4
-0.04 4
1.16 4
1.04 4
0.85 4
1.74 4
0.60 4
.
0. 32 4
0.25 4
-1.32 4
t df
-0.65 8
-0.29 8
0.92 8
0.06 8
1.32 8
-1.20 7
0.57 8
0.46 8
0.91 8
0.59 8
2.65* 8
1.02 8
-0.37 8
0.01 8
-0.74 8
0.97 8
-0.24 8
0.86 8
=================
-0.30 8
-0.32 8
2.75* 8
*Significant at 95% level
**Significant at 99% level
-------
TABLE VIII
RELATIONSHIP OF 10 SECOND ESTIMATIONS TO
CARBOXYHEMOGLOBIN SATURATION
Situation
Group
Al one
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
Baseline
Data
9.85 + 1.53
N = 591
10. 07+1. 8<
N = 57
10.36+1.56
N = 84
EXPOSURE DATA
0 - 2
10. 14+1. 6-i
N = 399
10.26+1.99
N = 18
10.40+1.60
N = 27
2.01 - 4
9.99+1.22
N = 123
N = 0
N = 0
4.01 - 8
9.91+1.15
N = 209
10.65+2.32
N = 13
10.90+0.69
N = 3
8.01 - 12
10.01 + 1.32
N = 183
10. 59+2. 3C
N = 15
10.12+2.37
N = 17
12.01 - 16
9.80+ 1.29
N = 166
N = 0
11. 87+. 49
N = 3
16.01 - 20
9.75+1.28
N = 114
N = 0
N = 0
0-20
9.98 + 1.41
N =1194
10.48±2.15
N = 46
10.42+1.84
N = 50
* 4-
Mean _ 1 Standard Deviation
-------
TABLE IX
RELATIONSHIP OF 30 SECOND ESTIMATIONS
TO CARBOXYHEMOGLOBIN SATURATION
Situation
G r oup
Alon e
B ooth
Baseline
Data
3 0.44*4. 2 <
N = 576
30.38*4.07
N = 52
32.02+3.6:
N = 83
0-2
31.07*4.7
N = 393
32.1614. 37
N = 17
32.57+4.31
N = 27
PERCEN:
2.01 - 4
30.41*4.1
N = 122
N = 0
N = 0
r CARBOXYHEMOGLOBIN LEVEL
EXPOSURE DATA
4.01 - 8 8.01 - 12 12.01 - 16 16.01 - 20
30.57*4.04
N = 208
33.99+5.15
N = 14
32.57*0.40
N = 3
31.11*4.03
N = 178
31.79*5.66
N = 15
32.48*4.31
N = 18
29.92*4.03
N = 162
N = 0
37.50+1.15
N = 3
29.20*3.53
N = 112
N = 0
N = 0
I 0 - 20
30. 5814.27
N = 1175
32.60*5.02
N = 46
32.83+4.17
N = 51
1
''" Mean 1" 1 Standard Deviation
-------
TABLE X
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TIME TEST AND CARBOXYHEMOGLOBIN SATURATION
1 SECOND SOUND - ESTIMATE/STIMULUS
Situation
Group
Al one
B ooth
PERCENT CARBOXYHEMOGLOBIN LEVEL
Baseline
Data
1.03*0.25
N = 392
0.941.23
N = 42
0.94t.21
N = 60
EXPOSURE DATA
0-2
1.26 ±.23
N - 16
N = 0
N = 0
2.01 - 4
1.19*. 24
N = 105
N = 0
N = 0
4.01 - 8
1.17*. 23
N = 200
0.88*. 24
N = 15
1.141.07
N * 3
8.01 - 12
M3±. 24
N = 162
0.971.28
N = 15
0.991.27
N « 21
12.01 - 16
1.07*. 26
N a 158
N = 0
0.781.10
N = 3
16.01 - 20
I. 06*. 22
N = 111
N = 0
N = 0
0-20
1.13*. 25
N = 752
0.92 + .26
N = 30
0.98f .26
N = 27
Mean ! 1 Standard Deviation
-------
TABLE XI
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TIME TEST AND CARBOXYHEMOGLOBIN SATURATION
3 SECOND SOUND - ESTIMATE/STIMULUS
Situation
G r oup
Al on e
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
Baseline
Data
*
1.081.17
N = 399
0.991.14
N = 39
1.00 + .16
N = 58
EXPOSURE DATA
0-2
1.021.24
N = 17
N = 0
N = 0
2.01 - 4
1.071.21
N = 108
N = 0
N = 0
4.01 - 8
1.091.17
N = 202
0.961.10
N = 15
1.121.16
N = 3
8.01 - 12
1.09 1.17
N = 166
0.961.09
N = 15
0.961.12
N = 21
12.01 - 16
1,091.19
N = 153
N = 0
0.951.06
N = 2
16.01 -20
1.081.19
N = 108
N = 0
N = 0
0-20
1.091. 18
N = 754
0.961.09
N = 30
0. 98 f .13
N = 26
Mean _ 1 Standard Deviation
-------
TABLE XII
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TIME TEST AND CARBOXYHEMOGLOBIN SATURATION
5 SECOND SOUND - ESTIMATE/STIMULUS
Si tuation
C r oup
Alone
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
Baseline
Data
*
1.03 + .13
N = 397
1.01 + .10
N = 40
0.96 + .10
N = 58
EXPOSURE DATA
0 - Z
l.Olt.ll
N = 17
N = 0
N = 0
2.01 - 4
1.03 +.14
N = 106
N = 0
N = 0
4.01 - 8
1.05 + .13
N = 184
0.95t.09
N = 15
0.98 ±.05
N = 3
8.01 - 12
1.07 ±.13
N = 167
0.97 + .10
N = 15
0.96±.ll
N = 20
12.01- 16
1.06 t.15
N = 160
N = 0
0.95 + .01
N = 3
16.01 - 20
1.05 + . 13
N = 113
N = 0
N = 0
0 - 20
1.05+.13
N = 747
0.96+.09
N = 30
0.96±. 10
N = 26
Mean 1 Standard Deviation
-------
TABLE XIII
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TIME TEST AND CARBOXYHEMOGLOBIN SATURATION
1 SECOND LIGHT - ESTIMATE/STIMULUS
Si tuation
G r ou p
A 1 one
Booth
Baseline
Data
1.001.26
N = 362
0.951.28
N = 42
0.961.24
N = 60
PI
0 - 2
1.211 .17
N = 17
N = 0
N = 0
:RCENT <
2.01 - 4
1.141.26
N = 110
N = 0
N = 0
3ARBOXYHEMOGL
EXPOSURE DATA
4.01 - 8 8.01 - 12
1.111.23
N - 198
0.901.22
N = 15
0.911.10
N = 3
1.071.25
N = 181
0.901.29
N = 15
0.971.17
N = 21
OBIN LE1'
12.01 - 16
1.021.25
N = 163
N = 0
0.701.13
N = 3
/EL
16.01 - 20
1.011.24
N = 114
N = 0
N = 0
0 - 20
1.071.25
N = 783
0.901.25
N = 30
0.931.18
N = 27
Mean _ 1 Standard Deviation
-------
TABLE XIV
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TIME TEST AND CARBOXYHEMOGLOBIN SATURATION
3 SECOND LIGHT - ESTIMATE/STIMULUS
Situation
G r ou p
Alone
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
EXPOSURE DATA
Baseline
Data
*
1.00 +.15
N = 366
0.96 + .15
N = 42
0.97+..14
N = 57
[0-2
1.03 + .14
N = 18
N = 0
N = 0
2.01 - 4
1.00 + . 13
N = 108
N = 0
N = 0
4.01 - 8
1.02 t. 12
N = 197
0.94 + .10
N = 15
1.01±.12
N = 3
8.01 - 12
1.03 + .13
N = 179
0.94 + .17
N = 15
0. 98 ±.15
N = 21
12.01 - 16
0.99 + .14
N = 163
N = 0
0.94*. 04
N = 3
16.01 - 20
1.01+ . 14
N = 114
N = 0
N = 0
0-20
1.01 + .13
N = 779
0.94 + .13
N = 30
0.97 + .14
N = 27
* Mean + 1 Standard Deviation
-------
TABLE XV
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TIME TEST AND CARBOXYHEMOGLOBIN SATURATION
5 SECOND LIGHT - ESTIMATE/STIMULUS
Situation
Group
Alone
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
Baseline
Data
*
0.99 + .13
N = 364
0.98 + .13
N = 40
0.981.11
N = 59
EXPOSURE DATA
0-2
0.98 + .06
N = 18
N = 0
N = 0
2.01 - 4
1.00 + . 10
N = 103
N = 0
N - 0
4.01 - 8
1.01 t. 10
N = 205
0.94 +.12
N = 15
0.95 +.07
N = 3
8.01 - 12
1.02+.11
N = 180
0.96 + .13
N = 15
0.96 + .12
N = 21
12.01 - 16
1.01 + .13
N = 159
N = 0
0.83 + .10
N = 3
16.01 - 20
1.02 + .13
N = 112
N = 0
N = 0
0 - 20
1.01 + .11
N = 777
0.95 + .12
N = 30
0.94 + .12
N = 27
Mean * 1 Standard Deviation
-------
TABLE XVI
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TEST AND CARBOXYHEMOGLOBIN SATURATION
1 SECOND SOUND - REACTION TIME
Situation
G r oup
Alone
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
Baseline
Data
V
0.32±.13
N = 391
0.241.16
N = 42
0.23 + .10
N = 59
0 - 2
0.24±.10
N = 18
N = 0
N = 0
2.01 - 4
0.291.12
N = 110
N = 0
N = 0
EXPOSl
4.01 - 8
0.29 *. 13
N = 201
0.261.13
N = 15
0.051.04
N = 3
JRE DATj
8.01 - 12
0.301. 14
N = 162
0.201.13
N = 14
0. 24t.l2
N = 19
\
12.01 - 16
0.33* .13
N = 152
N = 0
0.251.13
N = 3
16.01 - 20?
0.36±.13
N = 110
N = 0
N = 0
^JL-A0.
0.3li.l3
N = 753
0.231.13
N = 29
0.22 + .13
N = 25
'" Mean _ 1 Standard Deviation
-------
TABLE XVII
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TEST AND CARBOXYHEMOGLOBIN SATURATION
3 SECOND SOUND - REACTION TIME
Situation
Group
Al on e
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
Baseline
Data
*
0.30 +.12
N = 392
0.28 + .16
N = 41
0.21+ .08
N = 54
0-2
0.23 +. 08
N = 18
N = 0
N = 0
2.01 - 4
0.27+ . 10
N = 110
N = 0
N = 0
EXPOSU
4.01 - 8
0.27 t. 12
N = 201
0.28 + . 18
N = 15
0. 13 + . 10
N = 3
RE DAT/
8.01 - 12
0.271 . 11
N = 164
0.22 +.13
N = 14
0.21 + .11
N = 17
i
12.01 - 16
0.30 + .12
N = 153
N = 0
0.27 +.04
N = 2
16.01 - 20
0. 32 + . 12
N = 112
N = 0
N = 0
0 - 20
0.28i . 12
N = 758
0.25+.16
N = 29
0.20+ . 10
N = 22
v Mean 1" J Standard Deviation
-------
TABLE XVIH
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TEST AND CARBOXYHEMOGLOBIN SATURATION
5 SECOND SOUND - REACTION TIME
Situation
Group
Al on e
Booth
PERCENT CARBOXYHEMOGLOBIN LEVEL
EXPOSURE DATA
Baseline
Data
0.26 +.11
N = 396
0.18*. 12
N = 39
0.19 + .12
N = 58
t
0-2
0. 17t,06
N = 18
N = 0
N = 0
2.01 - 4
0.21 + . 10
N = 111
N = 0
N = 0
4.01-8
0.23 + .11
N = 182
0.21 + .10
N = 15
0.06 + .05
N = 3
8.01 - 12
0.23 + .09
N = 164
0. 141. 13
N = 15
0.21 j. 13
N = 16
12.01 - 16
0.26 + .10
N = 160
N = 0
0.15 + .07
N = 3
16.01 - 20
0.27 + .09
N = 112
N = 0
N = 0
0 - 20
• i n.»^i «. *_~-«u>,-._ ^-pr**
0.24+ . 10
N = 747
0.17 + .12
N = 30
0. 18f . 12
N = 22
Mean + 1 Standard Deviation
-------
TABLE xnc
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TEST AND CARBOXYHEMOGLOBIN SATURATION
1 SECOND LIGHT - REACTION TIME
Situation
G roup
Al on e
B ooth
PERCENT CARBOXYHEMOGLOBIN LEVEL
EXPOSURE DATA
BaBcline
Data
*
0.301.11
N = 353
0.241. 13
N = 39
0.21 1. 10
N = 54
0-2
0.211.06
N = 17
N = 0
N = 0
2.01 - 4
0.271.11
N = 108
N = 0
N = 0
4.01 - 8
0.271. 11
N = 200
0.231.11
N = i5
0.081.03
N = 3
8.01 - 12
0.271.10
N = 173
0.221.09
N = 15
0.191.11
N = 21
12.01 - 16
0.301. 11
N = 161
N = 0
0.241.03
N = 3
16.01 - 20
0.34 1. 11
N = 114
N = 0
N = 0
0-20
0.28*. 11
N = 773
0.231.10
N = 30
0.18+.11
N = 27
Mean + 1 Standard Deviation
-------
TABLE XX
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TEST AND CARBOXYHEMOGLOBIN SATURATION
3 SECOND LIGHT - REACTION TIME
Situation
Group
Alone
Booth
Baseline
Data
0.27 +.10
N = 360
0.22 + .13
N = 42
0.21+.07
N = 54
PERCENT CARBOXYHEMOGLOBIN LEVEL
EXPOSURE DATA
0-2
0.1 9 + .07
N = 18
N = 0
N = 0
2.01 - 4
0.24 +.08
N = 107
N = 0
N = 0
4.01 - 8
0.24 +.08
N = 193
0.28 + .18
N = 15
0.16 + .11
N = 3
8.01 - 12
0.26 + .09
N = 179
0.18 + .09
N = 15
0.19 + .07
N = 18
12.01 - 16
0.27 +.09
N = 158
N = 0
0.29 + .07
N = 3
16.01 - 20
0.29 +.08
N = 107
N = 0
N = 0
0 - 20
0.26 + .09
N = 762
0.23 + . 14
N = 30
0.20 +.08
N = 24
"' Mean 1 Standard Deviation
-------
TABLE XXI
RELATIONSHIP BETWEEN PERFORMANCE OF THE
MARQUETTE TEST AND CARBOXYHEMOGLOBIN SATURATION
5 SECOND LIGHT - REACTION TIME
Situation
G r oup
Al on e
Booth
Baseline
Data
0.26 + .11
N = 370
0.19 + .14
N = 36
0.18 + .1C
N = 58
F
0-2
0. 16 + .05
N = 18
N = 0
N = 0
'ERCENT
2.01 - 4
0. 18 ±.07
N = 109
N = 0
N = 0
CARBOXYHEMOG
EXPOSURE DAT
4.01-8 8.01 - 12
0.20 ±.07
N = 204
0.22±.15
N = 15
0.05±.01
N = 3
0.23+.08
N = 173
0. 15±.ll
N = 14
0.18 ±.13
N = 18
LOBIN LI
A
12. 01 - 16
0.25 + .11
N = 163
N = 0
0.23 + .05
N = 3
:VEL
16.01 - 20
0.28 ±.11
N = 114
N = 0
N = 0
0 - 20
0.23+.09
N = 781
0.18 + .13
N = 29
0.17±.12
N = 24
* Mean 1 Standard Deviation
-------
TABLE XXII
COMPARISON OF TESTING
SITUATIONS
EH
to
W
H
O
Pi
<
W
CQ
GROUP
17.73+ 2.26***; N = 395
-<*IT^*ft^iarstf^-f!-^^ '••—-Tf .•.-TTJg-:
ALONE
. *#*
17.67+2.74 ; N = 42
BOOTH
***
18.02+2.39 ; N = 59
BEARD TEST
BOOTH
F = 1.056
t •= .9115
F = 1.146
t = .683
ALONE
F = 1.210
t = . 160
GROUP
* Significant at the . 95 level
** Significant at the . 99 level
*** Mean 1 1 Standard Deviation
Note: Only baseline data used for this analysis
-------
TABLE XXIII
COMPARISON OF TECHNICAL PROCEDURES USED
BY TWO LABORATORIES PERFORMING TIME DISCRIMINATION TESTS
Procedure
Beard-We rtheim
Stewart, et al
Experimental Protocol
Single-Blind
Double-Blind
Chamber CO
Monitoring System
Single infrared instrument;
calibration standards not run
from within chamber. CO
concentration mean and
standard deviation not
reported.
Three, independent
monitoring systems;
calibration standards
run every hour from
within the chamber.
CO concentration mean
and standard deviation
reported.
COHb
Determinations
Blood obtained, results not
reported. COHb estimated
from breath samples in one
of two studies.
Hourly COHb determi-
nations made by two
independent methods.
Test Populations
Stanford University
students
Marquette University
graduate students and
Medical School
faculty.
Test Setting
Audiometric Booth
3 settings: audiometric
booth, subject isolated
in large room, subjects
tested in small groups.
-------
REFERENCES
1- Beard, R. R. , and Wertheim, G. A.: Behavioral Impairment Associ-
ated with Small Doses of Carbon Monoxide. Amer. J. Public Health.
57:2012-2022, 1967.
2. Beard, R. R. , and Wertheim, G. A. : Behavioral Manifestations of
Carbon Monoxide Absorption: Presented at the XVI International
Congress on Occupational Health, Tokyo, September 25, 1969.
3. Threshold Limit Values for Substances in Workroom Air Adopted by
ACGIH for 1972. American Conference of Governmental Industrial
Hygienists. Cincinnati, 1972.
4. Research Study to Determine the Range of Carboxyhemoglobin in
Various Segments of the American Population: Annual report for
October 1, 1970 - September 30, 1971, to the Coordinating Research
Council and the Environmental Protection Agency by the Department of
Environmental Medicine, The Medical College of Wisconsin; Report
No. : CRC APRAC CAPM-8-68 MCOW-ENVM-COHb-71-1.
5. Effects of Chronic Exposure to Low Levels of Carbon Monoxide on
Human Health Behavior, and Performance: National Academy of Sciences
and National Academy of Engineering, Standard Book No. 309-01735-1.
6. The Health Consequences of Smoking: A Report of the Surgeon General,
1972. U. S. Department of Health, Education and Welfare; Public
Health Service, 1972.
-------
7. Stewart, R. D. , Peterson, J. E. , Baretta, E. D. , Bachand, R. T. ,
Hosko, M. J. , and Herrmann, A. A. : Experimental Human Exposure
to Carbon Monoxide. Arch, of Environ. Health, 21:154-164, 1970.
8. O'Donnell, R. D. , Mikulka, P. , Heinig, P. , and Theodore, J. : Low
Level Carbon Monoxide Exposure and Human Psychomotor Performance.
Toxicol. Appl. Pharmacol. 18:593-602, 1971.
9. O'Donnell, R. D. , Chikos, P. , and Theodore, J. : Effect of Carbon
Monoxide Exposure on Human Sleep and Psychomotor Performance.
J. Appl. Physiol. 31:513-518, 1971.
!0. Bartlett, D. : Pathophysiology of Exposure to Low Concentrations of
Carbon Monoxide. Arch. Environ. Health. 16:719-727, 1968.
11. Air Quality Criteria for Carbon Monoxide: U. S. Department of Health,
Education and Welfare; National Air Pollution Control Administration
Publication, No. AP-62.
12. Dinman, B. D. : Pathophysiologic Determinants of Community Air
Quality Standards for Carbon Monoxide. J. Occup. Med. 10:446-
456, 1968.
13. Beard, R. R. : First Annual Conference on Environmental Toxicology,
9-11 September 1970. Statement made to the audience of scientists
during the discussion of his paper.
14. Stewart, R. D. : Use of Human Volunteers for the Toxicological
Evaluation of Materials. Symposium on An Appraisal of Halogenated
Fire Extinguishing Agents. National Academy of Sciences,
Washington, D. C.
-------
15. Stewart, R. D. , Newton, P. E. , Hosko, M. J. , and Peterson, J. E. :
The Effect of Carbon Monoxide on Time Perception. Report No. :
CRC APRAC CAPM-3-68 MCOW-ENVM-CO-72-1. Available at the
National Clearing House.
16. Aronow, W. S. , Harris, C, N. , Isbell, M. W. , Rokaw, S. N. , and
Imparato, B. : Effect of Freeway Travel on Angina Pectoris. Annals
of Int. Med. 77:669-676, 1972.
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-650/1-74-005
3. RECIPIENT'S ACCESSIOI*NO.
PB-214 651
4. TITLE AND SUBTITLE
The Effect of Carbon Monoxide on Time Perception
5. REPORT DATE
January 1973
6. PERFORMING ORGANIZATION CODE
7'RTcThHar
------- |