EXPOSURE OF HUMANS TO CARBON MONOXIDE COMBINED
                  WITH INGESTION OF ETHYL ALCOHOL
            AND THE COMPARISON OF HUMAN PERFORMANCE
 WHEN EXPOSED FOR VARYING PERIODS OF TIME TO CARBON MONOXIDE
    Report No.:  CRC APRAC CAPM-3-68 MCOW-ENVM-CO-74-2
    From the Department of Environmental Medicine, The Medical College of
                  Wisconsin, Milwaukee, Wisconsin  53226

    Supported by Contract CRC-APRAC, Project No.  CAPM-3-68, From the
Coordinating Research Council, Inc., and The Environmental Protection Agency

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       The automobile driver who is being exposed to carbon monoxide (CO)

while driving home after a social cocktail plus an analgesic to relieve his

tension headache is a common figure in our society. Consequently,

when trying to assess  the potential hazard of CO, the possibility of a

synergistic effect with commonly used drugs and ethyl alcohol must

be considered.   CO exposure along with ingestion of phenacetin or

diphenhydramine hydrochloride was  the topic  of a. previous report.   This

report presents the findings  of two sets of experiments, referred to as

Study A and Study B designed to assess the effects of CO and ethyl alcohol

on behavioral test performance and  to assess the effects of a 24-hour

exposure as compared .to a 5-1/2 hour exposure  to identical concentrations

of CO.


                             STUDY A
                                                              /

       In the fall of 1970, four experiments were conducted to study the

effect of the following  agents on man:  carbon monoxide,  ethyl alcohol,

carbon monoxide plus  ethyl alcohol and ambient air. Because it was not

desirous to have inebriated subjects incapable of performing the tests,

a low dose level of 1. 6 ml -  100  proof alcohol/kg body weight was chosen.

The alcohol experiments were conducted immediately after completion

of experiments defining the effect of CO on time  perception,  reported

earlier.  Consequently, a CO exposure level of 200 ppm was retained.

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                                 -2-
                             METHODS



Protocol

       Thirty minutes prior to each exposure the subjects were given an

interim physical examination at which time they were questioned about

subjective feelings including nausea,  headache, dizziness,  chest pain,

abdominal pain and eye, nose and throat irritation.  Pre-exposure blood

samples were also obtained at this time for determinations of percent

carboxyhemoglobin concentration (COHb).

       During the first 150 minutes of each exposure, time tests were

performed and correlated with the corresponding COHb saturations.
                                              (1)
The results of these tests were  reported earlier.  Between 150 and 195

minutes of exposure time each subject was given 1.6 ml alcohol (Smirnoff's

Vodka) per kilogram body weight mixed with orange juice and equally divided

between three drinks.   The subjects were given 15 minutes to finish  each

drink. After completion of the drinks,  a blood sample was obtained

for blood alcohol and % COHb determinations.  Immediately following

the blood sampling, the behavioral tests were administered over the next

30 minutes and the exposure was terminated at 240 minutes.  A post

exposure blood sample was then  obtained for blood alcohol and % COHb

determinations.

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                                  -3-
Subjects

       The subjects were five male and one female sophomore medical

students,  ranging in age from. 22 to 26 years,  selected from a larger group

of volunteers on the basis of being in good health and because of their

expressed willingness to expose themselves to CO. Prior to their selection,

subjects were completely informed as to the purpose of the experiments

and the potential  hazard to themselves.  Subjects were paid $1. 50 per hour

for each hour in the chamber, with a bonus of $1. 00 per hour conditional

upon satisfactory completion  of the study.  Baseline % COHb saturations

attested that all six subjects were nonsmokers.  Prior to  and after com-

pletion of the study, each subject was given a  comprehensive medical

examination which included a complete  history and physical examination,

a 12-lead EKG and an EEG using the standard 10-20 electrode configuration.

Exposure Chamber

       All CO  exposures were carried out  in the controlled environment

chamber located  in the Department of Environmental Medicine,  The Medical
                   (1)
College of Wisconsin.  The environmental system  (Carrier) provided

accurate control  of temperature (72 +_ 2°F) and relative humidity (40 4^5% RH)

within the chamber, a room measuring 20 x 20 x 8 feet.   The chamber was

operated at a slight negative pressure with an air circulation rate of 1, 200 cfm.

Exhaust and makeup air capacities of 1,000 cfm provided  a rapid chamber

flushing capability when desired.   The chamber featured pleasant lighting,

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                                  -4-
comfortable chairs, individual testing carrels and a restroom facility.





The subjects were under continuous visual surveillance by medical personnel




while in the chamber,  and in addition, their activities were visually




monitored and periodically video taped by closed circuit TV (Sony).




Exposure Chamber Atmosphere




       On non-exposure days,  outside ambient air was flushed through the




chamber.  On exposure days, CO was continuously metered into the




chamber's environmental system from a  compressed gas cylinder in the




adjacent command laboratory.   Chemically pure CO with a minimum purity




of 99. 5% was used.  The concentration of CO in the chamber atmosphere




was continuously recorded from an infrared spectrophotometer (Beckman




IR-10) equipped with a 10-meter path-length gas cell which was continuously




flushed with air drawn from the chamber through 1/4"  diameter polyethylene




tubing.  An MSA CO Meter and Alarm, Model 701, also independently




sampled chamber air to provide a second independent means of continuously




monitoring chamber concentration.  The  chamber atmosphere was also




periodically monitored by  a gas chromatograph (GC)  (Varian Aerograph)




equipped with a  sequential sampler.




       All three methods of monitoring CO concentration during an exposure




were  calibrated from within the chamber with standards prepared in saran bags,

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                                  -5-
Analysis of Carboxyhemoglobin Saturation





       Five-ml. aliquots of venous blood were collected in Vacutainer




tubes containing edetic acid and immediately analyzed for the hemoglobin




concentration and the percent carboxyhemoglobin saturation using a




CO-Oximeter (Instrumentation Laboratories, Inc.).




Behavioral  Tests




       The Flanagan Coordination Test (Science Research Associates, Inc.,




259 East Erie Street,  Chicago,  Illinois) measured the subject's ability to




rapidly and accurately follow a spiral pathway with a pencil.  The subject,




while sitting comfortably at a desk in the individual carrel, was allowed




40 seconds to complete each of 6 spirals.  The first two were considered




practice  and the last four were scored and totaled.  The score was determined




by the distance covered in each spiral minus the number of times the




sides of the spiral were touched with the pencil and had a maximum of 100.




       The random number inspection test measured the speed with which




a subject could detect  the number "3" in rows  of random numbers on an




8-1/2 x 11  inch page.  The subject was asked to inspect each row of




numbers beginning at the top of the page and mark as many 3's as possible




in two minutes.  The subject's score was the total number of 3's  struck




with an unachievable maximum score of 203.  Ten different pages of random




numbers were used sequentially to prevent memorization of test answers.

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                                  -6-
       The arithmetic test,  which measured the subject's ability to work





with numbers,  was divided into two parts.  The first part, timed at five




minutes, consisted of simple addition and subtraction problems while the




second part, timed at three minutes,  consisted of multiplication and




division.  The  maximum score available, if all answers were correct,




was  125; however,  no subject completed the test in the allotted time.  In




order to prevent memorization of answers, ten different tests generated




from random number tables  were used sequentially.




       The Crawford collar-and-pin test, (produced by The Psychological




Corp. .  304 E.  45th Street, New York, New York 10017) measured a




subject's manual dexterity.  The test required the subject to use forceps




to pick up a pin (0. 657" long, 0. 063" diameter), place the pin in a hole




(0.08" diameter) and place a loosely fitting collar  over  the pin.   The test




score was the number of collar and pin  combinations  placed in three minutes




and had a maximum of 42.




Hand Steadiness Test




       In the AAA hand  steadiness test,  a subject passed a hand-held




metal wand down through a gradually narrowing V-shaped vertical slot.




Contact with either side  of the slot completed an electrical circuit which




flashed a light.  The  slot was numerically graduated for recording wand

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                                  -7-






position, and the score was tabulated by an observer who totaled the results




of five trials.  The test had a maximum score of 80 and took 1 minute to




perform.




Data Analysis




       Data  analysis of the behavioral test scores used an analysis  of




variance for two factors.  The within treatments mean  square was used
                                                       o



as the estimate of uncontrolled variability in calculating F ratios.






                              RESULTS






       The blood alcohol levels and COHb saturations determined for




each subject at the conclusion of each of the four experiments are presented




in Table 1.   Subject K. H.  (native Chinese) could not tolerate this level




of alcohol and was not given any alcohol after the first drink on the first




day.  His data  were, not included in the final analysis.   The remaining




subjects displayed the usual post alcohol ingestion periods of gaiety followed




by drowsiness.  They remained in good health throughout the study.




       Table 2 presents the analysis of variance (AOV) F ratios and their




significance.  A significant F value appears that CO had an effect on the




performance of the collar and pin test.  However, this  effect was  an increase




in test score,  or an improvement in test performance.  The Coordination




Test performance was  affected by alcohol but not by CO.  The test data




reveals this  effect was a  decrease in test performance.  Performance  of




the Arithmetic Test and Hand Steadiness Test were not affected by either




alcohol or CO  at these  levels.

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                                  -8-
                             STUDY B







       The  second series of experiments was conducted in the fall of 1972,




and had several distinct differences from the first series: exposure for




24-hours were included, CO exposure was lowered from  200 to 70 ppm and




30 ppm but the steady state  % COHb saturation was reached by an initial




30 minutes at 1, 200 ppm, and behavioral testing was conducted under the




direct supervision of an experimental psychologist.   Simultaneous exposure




to ethanol and CO was conducted as  the last experiment in this series.







                             METHODS







Protocol




       To obtain information on the prolonged'effects of CO exposure,




four subjects were  selected to remain in the chamber overnight for 24 hours,




being exposed continuously to CO concentrations of 0, 30, or  70 ppm.  A




total of six 24-hour sessions were run--three at 0 ppm,  one at 30 ppm,




and two at 70 ppm.




       For  the 30  ppm  session, there was an initial 20-minute exposure




to 1,000 ppm CO,  which caused a rapid  rise of COHb saturation to ap-




proximately 5%.  For one of the 70 ppm sessions, an initial 30 minutes




at 1,000 ppm caused a rapid rise of COHb saturation to approximately 10%.

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                                 -9-
       CO concentration levels were presented in a random, order and





every attempt was made to prevent subjects from knowing the CO concen-




tration present during a given session.  Questionnaire data obtained at




the end of each session confirmed subject's naivete in this regard.  The




four 24-hour subjects,  together with four other subjects who left the chamber




overnight,  were given behavioral tasks to perform during the first 5 hours




and during the last 5 hours of this 24-hour period.   A comparison of




performance of the 24-hour subjects between  the first and the last 5-hour




test periods was made to determine the effects of prolonged CO exposure.




In addition, all eight subjects were exposed to the three concentrations




of CO during regular  5-hour sessions  which were scheduled the day




before the  24-hour sessions.  Four, 5-hour sessions were held, two




sessions at 0 ppm,  one at 30 ppm,  and one at 70 ppm.  As with the 24-hour




sessions, exposure concentrations  were selected randomly for the 5-hour




sessions.  The purpose of the 5-hour  sessions was to obtain additional




information on the effects of CO during short  exposures.




       To  determine whether alcohol potentiated the effects  of CO,  all




subjects  were studied during two separate 5-hour sessions.  These sessions




occurred as the final two sessions of the experiment.  During the first




of these  sessions, subjects were given 1.5 ml 100% proof alcohol/kg body




weight and exposed to a CO concentration of 70 ppm. During the second

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                                  -10-

ses sion, which occurred the next day,  subjects were given the same amount of
                                                                                  i
alcohol but no CO was present in the chamber.  As always,  subjects were unaware
of actual CO concentrations.
Subjects
        The  subjects were eight male college students,  ranging in age from  20
to 26 years.  Of the eight subjects,  six were nonsmokers and two were light to
moderate smokers  who were requested to refrain from smoking  for the duration
of the study.
Behavioral Tests
       Subjects were tested simultaneously while seated at two tables in the
environmental chamber.  Partitions on the table tops extended several inches
beyond the edge of the tables thus reducing visual interaction among subjects
and providing a somewhat isolated testing area  for each subject.  All behavioral
tests were administered under the direct supervision of an experimental psychol-
ogist and were  the same as  in the first set of experiments (A) except for the
deletion of the Crawford Collar and  Pin Test and the Hand Steadiness Test,  and,
the addition of the Time Estimation  Tests and a Vigilance  Test which are described
below.
       The vigilance test required subjects to detect and report  a complex
visual signal presented intermittently over an extended period of time.  The
test  apparatus consisted of eight General Motors readiness-to-drive consoles,
one for  each subject.  During the test,  the subject sat facing his console and
random four-digit numbers  were briefly flashed on a front window of the
console after which he pressed the number back into the consol via the
console keyboard.  Flash duration was 0.7 seconds and the time interval
between numbers averaged 18 seconds during a brief,  3-minute alert phase,
and 90 seconds during a subsequent  45-minute phase.  Subjects remained

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                                  -11-
at the task for 48 minutes followed by a 12-minute rest period.  This

procedure continued until 4 hours had elapsed with the beginning and end

of each 48-minute session indicated by the offset and onset, respectively,

of a light  on the console.  Over the 4-hour period, 160 four-digit numbers

were presented  to each subject.  The number of four-digit numbers correctly

reported within  5 seconds after the number was flashed defined the vigilance

performance of  a given subject.  Subjects reported the numbers by pressing

appropriate buttons on the front of the console,  labeled 0 to 9, in the  same

sequence  as the number which had been presented.  The 5-second period

allowed for reporting the  number was identified by a white light on the console.

Immediate feedback was provided to each subject in the form of a  green

or red light which flashed briefly at the end  of the  5-second interval,  depending
                                                a
on whether the number  was reported correctly or incorrectly.  Unlike the

other behavioral measures,  subjects were not given  extensive training  on

the vigilance test prior to the experiment because  performance on this

sort of task which does not test reaction time does not appear to improve

with practice.  A single 4-hour practice session was conducted to insure

that subjects understood the procedure and to familiarize  them with the

apparatus.  During this practice session, and at various times throughout

the experiment, subjects  were instructed not to talk  or interact in any way

with other subjects so as  to minimize distraction during the test.

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                                  -12-
       The Marquette Time Test consisted of a series of nine tone stimuli


followed by a series of nine light  stimuli.  Each series contained stimuli of


approximately  1.0, 1.5, . . .  5.0 sec.  duration presented in random order.


At termination of each stimulus,  the subject depressed a push button switch


for that interval of time  he estimated to be equal in duration to that of the


original auditory or light stimulus.  This provided a measure of his ability


to estimate the duration  of the stimulus; the interval between stimulus


termination and onset of the response -was a measure of reaction time.


       The ten-and thirty-second time estimation tests consisted of each             ',',


subject depressing the push button described above  for an interval  equal


to that desired (10  or  30 seconds).  This -was repeated an additional two


times for each test.


                                                                                   !)
                              RESULTS
                                                                                   !!

                                                                                   ii

       The blood alcohol levels and % COHb saturations obtained from Study  B


are presented in Table 3.  The subjects displayed the usual post alcohol              j
                                                                                   ii
                                                                                   11
ingestion periods of gaiety and then drowsiness.  They remained in good health

                                                                                   .11
throughout the experiment.                                                         jj
                                                                                   ' ii

       Comparison of data obtained from the behavioral testing during the


experiments designed to bring the % COHb saturation to a plateau very
                                                                                   I j|
quickly to that data obtained during experiments when this plateau was                '.'••
                                                                                   ii

reached in a 5 or 8 hour period revealed no  significant difference in performance.


Therefore,  all data from the 30 ppm or 70 ppm exposures were averaged

                                                                                   i
for a comparison of the performance at 1 hour of exposure versus  24 hours of
                                                                                   Fl
exposure.                                                                          j

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                                   -13-
Coordina.tion Test




       Figure  1 presents performances of the four 24-hour subjects and




1 and 20 hour of exposure to 0, 30 and 70  ppm of CO.  Comparisons of




performances during the 1st and 20th hour indicates the degree to which




subjects were affected by CO after prolonged exposure.  It is apparent that





there were no consistent changes in coordination for subjects exposed to




0 or 30 ppm CO for  20 hours.  While all four subjects  showed slight




improvements  in coordination performance after 20 hours of exposure to




70 ppm,  the small magnitude of the mean  difference and the large amount of




variability,  as  expressed by the  standard  errors, provide little confidence




in the reliability of this  finding.




       Figure  2 shows coordination performances during the last two




sessions of the experiment when subjects  were given alcohol plus CO




(70 ppm) or alcohol  alone.  Clearly,  there was no systematic tendency




for alcohol to potentiate  the effects of CO  relative to alcohol-along baselines--




four subjects showed decreased coordination with alcohol plus  CO while the




remaining four showed increased coordination.




       Finally, Figure 3 summarizes overall coordination performances




under each condition of the experiment. Again it is apparent that subjects




did not show systematic  changes in coordination performance in response to




CO; however, all subjects did show deteriorations in coordination following




ingestion of alcohol  and  as demonstrated in the AOV (Table 4), this was found




to be highly significant.

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                                   -14-
Arithmetic Test




       Figure 4 presents arithmetic scores of the 24-hour subjects under




each concentration of CO and allows a comparison of performances obtained




during the 1st and 20th hour of the 24-hour sessions.  As may be seen,




arithmetic performance did not change with prolonged exposure to  CO,





regardless of concentration level.




       Figure 5 shows, in addition, that alcohol did not systematically




potentiate the effect of  CO.   Three subjects showed a decrease in arithmetic




scores but the remainder showed an increase  in arithmetic scores  when




alcohol was  combined with  CO.




       From Figure 6  and from the AOV (Table 4),  alcohol as a treatment




variable  had little effect on ability to solve arithmetic problems, at least




at this blood alcohol level.




Inspection Test




       Mean and individual inspection scores  of the  24-hour  subjects after




the 1st and after the 20th hour of CO exposure are shown in Figure 7.   Only




one slight but systematic trend is apparent. Under 70 ppm CO, all four




subjects  showed decreases  in scores after  20 hours  of exposure to  CO.




This finding is in contrast to the slight increase that was noted in coordination




after prolonged exposure to 70 ppm CO.  As such, and until  this finding




can be reliably reproduced  in future research, it is  best viewed as an




artifact of the small number of subjects employed in the present study.

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                                   -15-
       Figure 8 shows the inspection scores of each subject in response




to alcohol plus  CO (70 ppm) and to alcohol alone.  Clearly,  there is no




consistent tendency for alcohol to potentiate the  effect of CO on performance




of this test since some subjects showed decreased scores while others




showed an increase.




       Looking at the overall data obtained on the inspection test under




each condition of the  experiment, summarized in Figure 9 and in the AOV




Table, Table 4, it is apparent that the inspection test was not a sensitive




measure of responses to either CO or alcohol at these levels.




Time Tests




       The AOV F values in Table 4 show that neither time estimations




nor reaction time was affected by either CO or alcohol for either sound or




light stimuli.




Vigilance Performance




       Interpretation of the data obtained from the series of vigilance




tests must take into account the adequacy of the  test procedures followed.




Unfortunately,  for the reasons given below,  the  circumstances under which




the vigilance data were collected create serious questions about the validity




of the data.




       A vigilance task has usually been defined as one in which an individual




is required to respond to unpredictable signals in fairly isolated and non-eventful




surroundings over long periods of time.  For this reason,  group-testing

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                                   -16-
procedures are not conveniently used in the study of vigilance.  When




subjects work together in groups,  especially over extended periods of time,




there is the distinct possibility of uncontrolled social interactions •which




will distort performances.   Furthermore, such distortions generally




will be  in the direction of heightened efficiency, thus complicating efforts




to detect behavioral effects of CO or any other toxic substances.




        The design of the present study was predicated on the assumption




that it •would be possible to prohibit interactions among subjects during




prolonged group testing of vigilance performance  so that valid data could




be obtained. Unfortunately, social interaction could not be prevented.




Despite efforts  to enlist the cooperation of the subjects, including repeated




admonishments, a variety of, interactions were observed to occur among




the subjects including talking,  singing, whistling, eye-to-eye contact




and even on one occasion,  the  playing of a game of chess.   For these reasons,




the data presented below can hardly be viewed as adequately answering  the




question of whether low levels of CO can influence vigilance performance.




Their main value  is to indicate the inadequacy of group procedures  as a




method  for  studying vigilance performance in reaction to CO.




        Figure  10  shows the mean and individual vigilance scores of the




24-hour subjects as each concentration of CO during the first and last 4 hours

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                                  -17-
of the Z4-hour sessions.  The only apparent trend is a minor increase in


vigilance  scores during the last four hours of the 70 ppm CO sessions.  Com-
              t

parisons of the vigilance performance of each subject under alcohol plus


CO (70 ppm) versus alcohol alone, shown in Figure 11, do not indicate


any trend for alcohol to potentiate the effects of  CO.  Of the eight subjects,


four showed increased and four showed decreased vigilance performance


under the CO-plus-alcohol condition.


       Figure 12 summarizes  performance under each treatment condition


of the experiment.  As can be seen, there were  no differences across CO


levels.  Figure  12 does indicate substantial decreases in vigilance  performance


under alcohol, an effect present in every subject.  That alcohol will


result in disruptions of performance requiring sustained attention is a


well-established finding, and in the context of the present study shows


that the group testing procedure,  despite its inadequacies, was not totally


insensitive to the effects of alcohol.


       An important characteristic of vigilance  performance is that it


deteriorates progressively over extended test sessions. Figure 13, which


presents scores during each of the four hours  shows that this did not occur


in the present experiment.  If there is any trend, it is that scores were


lowest during the second hour and gradually increased to a maximum during


the fourth hour.   (In the case of the alcohol condition this pattern may


have been caused by the decrease in blood alcohol level with time. )  The

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                                  -18-
general finding that vigilance performance did not deteriorate during the

tests bears out the aforementioned conclusions concerning  the inadequate

sensitivity of the procedures.  It is likely that interactions ensuing

between the subjects during testing permitted them to maintain a high level

of alertness during the 4-hour course of the tests.  Any subtle behavioral

effects of CO on vigilance would be effectively masked under these conditions.



                             DISCUSSION



       The purpose of these two studies was to  test the hypotheses that a

24-hour exposure to low levels of CO would have deleterious effects  on behavior

and that alcohol would potentiate such effects.  The data obtained from tests

of coordination, arithmetic ability, inspection,  manual dexterity,  time

estimations and vigilance  did not provide evidence to substantiate either

of these hypotheses.

       The lack of CO effect was not unexpected as previous studies in this
                                                                          (1)
laboratory for acute exposure  have shown no effect of CO on time estimations,
                                     (2)
arithmetic, inspection or  coordination.

       The experimental design did not include  replicates of each exposure

combination and thus CO-alcohol interactions could not be calculated.  From

the mean  scores,  however,  there was no evident synergistic effect of the two.

Negative findings  place a special burden on the researcher obtaining such

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                                   -19-
findings.  They may reflect the fact that the variable in question indeed

has no influence.  But it also is possible that negative findings reflect

inadequacies of the experimental method,  such as sample size, insensitive

procedures,  and  the lack of control of extraneous variables.

       Investigators working in another laboratory have reported per-
                                                                  (3,4)
formance decrements  as a  consequence of exposure to low levels of CO.

The present  results,  on the other hand, as well as  those of several other
                                           (1,5,6,7)
prior investigations have not indicated such effects.  The issue is whether

these differences in findings should be interpreted to mean that CO has no

behavioral effects, or whether some procedures are insensitive  to real

effects.

       There are at least three aspects of the behavioral testing procedures

of this work which may have contributed to negative results.  An obvious

factor concerns the procedure of testing groups of subjects  rather than

individual subjects.  It may be more than coincidence that Beard, who has

obtained positive results, has characteristically studied subjects one at

a time.  If low concentrations of CO do have behavioral effects,  those

effects seem most likely to appear under conditions of isolation.  Testing

in groups undoubtedly  created states of alertness and arousal which may

have effectively masked subtle cognitive and perceptual-motor effects

of CO.  However, a test of  that hypothesis  conducted using individual

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                                   -20-
subjects in an experimental design identical to Beard's showed no deleterious
             (1)
effects of CO.  Group interaction then does  not appear to be an applicable

explanation in this case.

       A second factor possibly contributing to error  and insensitivity

involves social relationships which may develop between subjects and

the research staff.  In some respects the  procedures in this laboratory

are informal and may be characterized as treating subjects more as

collaborators in the research endeavor than as subjects.  Even though

approach may not be inappropriate for strictly physiological or medical

work, it is a potential source of serious experimental error in behavioral

work.  It is advisable, if not essential,  to develop more formal procedures

which will reduce as much as possible social interactions between subjects

and the  research staff.  These procedures must begin at the point that

the subject is enlisted into the experiment, and should be followed strictly

at every point along the way.  Only by imposing this sort of rigor will

it be possible to observe behavioral reactions to CO uncontaminated by other

variables.

       Finally,  and quite apart from the question  of experimental control,

is the question of test sensitivity.  There  are no simple rules that can

be applied to determine which behavioral measure stands the best chance

of revealing changes in response to CO, and there 'was justification for using

the tests of the present experiment.  There  is  reason  to believe that highly

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                                  -21-
skilled performances will be resistant to disruption by toxic agents, and





for this reason training before testing may have worked against the possibility




of detecting CO effects.  In any case, to show subtle behavioral effects,




tests at least potentially  sensitive to many variables must be used.  The




present study showed no  decrements on tests of inspection, arithmetic




ability,  or time estimations under the influence of alcohol.  A test which




is insensitive to alcohol could probably  not be expected to be sensitive




to CO.  However, these are the tests which other investigators have shown




to be affected by  CO and, therefore, they were included in this research.







                             SUMMARY







       The purpose of  these two studies was to test the hypothesis that




a 24-hour exposure to low levels  of CO  would have deleterious  effects  on




behavior and that alcohol would potentiate such effects.  The data  obtained  ^




from both studies for tests of coordination, arithmetic,  inspection, manual




dexterity,  time estimation, and vigilance did not provide evidence to substantiate




either of these hypotheses.  The only positive result was alcohol adversely




affects eye-hand  coordination.





                       ACKNOWLEDGEMENTS





       The authors gratefully acknowledge the technical assistance of




S. Graff,  K.  Donohoo,  D. Fleischfresser and K.  Kujawski.   They also




thank Miss Susan. Kamke  for her help in preparation of this manuscript.

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                                 -22-
                           REFERENCES
1.     Stewart, R. D. ,  Newton, P.E.,  Hosko, M. J.  and Peterson,  J. E. ,
       "The Effect of Carbon Monoxide on Time Perception",  (a) CRC
       Report No. CRC APRAC CAPM-3-68, MCOW-ENVM-CO-72-1,
       (b) Arch.  Environ.  Health: 27:155-160, 1973.

2.  •   Stewart, R.. D. ,  Newton, P. E. ,  "The Effect of Carbon Monoxide
       on Eye-Hand Coordination, Manual Dexterity and Mathematical
       Abilities", unpublished report.

3.     Beard,  R. R.  , Wertheim, G.A. , "Behavioral  Impairment Associated
       with Small Doses of Carbon Monoxide", Am. J. Public Health 57:2012-2022,
       1967.

4.     Beard,  R. R.  , Wertheim, G. A. , "Behavioral  Manifestations of
       Carbon  Monoxide Absorption",  read before the 16th International
       Congress  on  Occupational Health, Tokyo, 1969.

5.     Stewart, R. D. ,  et al,  "Experimental Human Exposure  to Carbon
       Monoxide", Arch. Environ. Health, 21:154-160,  1970.

6.     O'Donnell, R. D. , et al,  "Low Level Carbon Monoxide Exposure
       and Human Psychomotor Performance", Toxicol. Appl. Pharmacol. ,
       18:593-602, 1971.

7.     O'Donnell, R. D. , Cherkos, P.,  Theodore,  J. ,  "Effect of Carbon
       Monoxide  Exposure on Human Sleep and Psychomotor Performance",
       J. Appl. Physiol. ,  31:513-518,  1971.

-------
                                       TABLE 1

SUBJECT BLOOD ALCOHOL LEVEL AND PERCENT CARBOXYHEMOGLOBIN SATURATION
               IMMEDIATELY FOLLOWING TESTING SESSION - STUDY A
              Exp.  1
Exp. 2
Exp. 3
Exp. 4
SUBJECT
R.S.
F.G.
D. T.
T.K.
.K.H.
T.M.
Blood
Alcohol
mg. %
--
--
--
--
--
--.
COHb
0.4
0.3
1.0
1.4
1.0
0.9
Blood
Alcohol
mg. %

--
--
--
--
--
COHb
15.9
14.5
N.A.
15.2
N.A.
14.9
i
Blood
Alcohol
mg. %
! 48.2
36.6
69.9
45.6
. <-5
46.8
COHb
0.6
0.7
1.6
0.6
0.5
0.5
Blood
Alcohol
mg. %
50.7
52.7
74.0
82.0
< .5
42.0
COHb
15.2
13.6
15.4
13.8
13.9
13.9
                                                                                                 CO

-------
                                     -24-
                                 TABLE 2
   ANALYSIS OF VARIANCE FOR THE EFFECT OF CARBON MONOXIDE
        AND ETHYL ALCOHOL ON BEHAVIORAL TESTS - STUDY A
   TEST                   EFFECT             df         F Ratio

Collar and Pin


Coordination


Arithmetic


Hand Steadiness
  Significant at p <. 01
  Significant at p <  .05
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
1
1
1
1
1
1
1
1
15.75^
#:
121.00
*
60.49
1.49
1.67
0.69
1.47
0.01

-------
                             -25-
                         TABLE 3

          SUBJECT BLOOD ALCOHOL LEVELS AND
PERCENT CARBOXYHEMOGLOBIN SATURATION IMMEDIATELY
           PRIOR TO TESTING SESSION - STUDY B

SUBJECT
J.H.
J.R.
R.S.
R. C.
B. F.
E.G.
S.P.
J.W.
Exp.
Blood
Alcohol
mg. %
45.3
58.8
58.2
59.2
54.3
58.8
59.9
60.5
1
COHb
8.7
7.8
9.1
9.3
9.5
8.7
8.4
9.1
Exp.
Blood
Alcohol
mg. %
27.9
56.3
42.3
37.4
54.2
48.4
53.7
51.1
2
COHb
1.5
0.9
0.5
0.21
0.5
0.4
0.4
1.0

-------
                                  -26-
                              TABLE 4
    ANALYSIS OF VARIANCE FOR THE EFFECT OF CARBON MONOXIDE
        AND ETHYL ALCOHOL ON BEHAVIORAL TESTS - STUDY B
       TEST

Marquette:
 Sound Stimulus:
       Es timate /Stimulus
        I Estimate-Stimulus
       Reaction Time
  Light Stimulus:
       Estimate/Stimulus
        I Estimate-Stimulus
       Reaction Time
        10 Second Estimations
       30 Second Estimations
 Arithmetic:
Coordination:
 Inspection:
EFFECT
df
F RATIO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
Alcohol
CO
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1

3.23
0.36
4.25
0.34
0.04
0.13
15.98
' 35.96
26.10
31.31
1.39
1.00
0.58
0.00
0.01
0.70
0.72
0.01
718.67*
8.53
0.87
0.08
 ^Significant at p< .001

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