Perceptual and Motor Skillr, 1991, 73, 551-554.

O Perceptual and Motor Skills 1991

OLFACTORY FUNCTION I N CHRONIC ALCOHOLICS ' J. PATRICK KESSLAK AND BEATRICE F. PROFITT Departmen/s o/ Neurology and Psychobiology, University of California, Irvine PHILLIP CRISWELL

Veterans Administration Hospital, Long Beach, CA Summary.-8 patients participating in an outpatient program for chronic alcohol abuse and 8 age-matched controls were tested for olfactory function. There was a significant difference between the two groups on a match-to-sample test using uncommon odors but not on a smell identification test using common odors. Ability to detect and identify common odors does not appear to be impaired by chronic alcohol abuse. Deficits on the odor-matching task may be related to difficulty in encoding olfactory information rather than a primary olfactory deficit.

Several studies have shown that cognitive and sensory deficits are associated with chronic alcoholism. Williams and Skinner (1990) found that a "high-alcohol" consumption group scored significantly lower than did a "lowalcohol" consumption group on several tests of cognitive performance. Gregson, Free, and Abbott (1981) showed that Korsakoff patients differed significantly from nonalcoholic controls both in labelling of odors (choosing from a list of possible descriptions of odors) and in odor naming (no verb2 clue given). I n this same study alcoholic controls differed significantly from Korsakoff patients but did not score as well as nonalcoholic controls. The behavioral deficits observed as a consequence of chronic alcohol consumption may result from a neurodegenerative state induced by toxic effects of alcohol. Previous studies with other progressive neurodegenerative disorders have also reported significant alterations in the sense of smell (Schiffman, 1983; Kesslak, Cotman, Chui, Van Den Noort, Fang, Pfeffer, & Lynch, 1988). I n this study we examined subjects with histories of chronic alcohol abuse for their ability to identify common odors and use uncommon odors in a memory task. The relationship of olfactory performance to duration and extent of alcohol abuse and to the duration of abstinence were also examined.

METHOD Subjects Eight volunteers from a substance abuse program at a VA hospital and 'This work has been supported in part by grants from the Alzheimer's Disease Research Center of Los Angeles and Onnge Counties (AGO 5142) and the PEW Charitable Trusts. Address correspondence to J. Patrick Kesslak, Ph.D., Department of Psychobiology, University of California, Itvine, Irvine, CA 92717.

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J. P. KESSLAK, E T A L

eight age-matched controls with no history of alcoholism participated in the study. For all participants, there was no history of mental illness, head trauma, or other impairment, as given by self-report, that might alter cognitive or olfactory function. I n the alcoholic group, length of abuse ranged from 13 to 42 years (mean of 26.37k3.75 SE), duration of pretest sobriety ranged from 0 to 72 months (mean of 28.37 & 10.67 SE), and the amount of alcohol consumed daily (standardized to 40% alcohol) was between11 and 44 oz. (mean of 26.25k3.97 SE). Mean age was 54.4 yr. for the alcoholics and 54.3 yr. for the controls. The age range for both groups was 3 1 to 69 years. Measures Universi~of Pennsylvania Smell Identification Test.-The UPSIT (Sensonics, Inc., Philadelphia, PA) was administered using the standardized instructions provided with the test. The test consists of 40 micro-encapsulated common odors that are released by scratching an odor label. The subject then identifies the odor by selecting one of four possible choices. Previous studies have shown the test to be highly reliable (Doty, Shaman, & D a n n , 1984). Olfactory match-to-sample test.-An odor match-to-sample test (MST) was also administered (Kesslak, et al., 1988). Participants were presented with a "target" odor, followed by three choice odors and were asked to pick the choice that best matched the target odor. The test was composed of 15 sets of uncommon odors (International Flavors and Fragrances) each with a different target odor. An odor identical to the target was always included and the position of the correct choice was random. There was a 10-sec. delay between presentation of the target odor and each choice for matching. Both tests were administered in a well-ventilated room. During olfactory testing, subjects were frequently asked if their abdity to detect odors was diminishing (saturating) and if they wished to take a break to clear their noses. No apparent problem with saturation was observed.

RESULTS Subjects in the alcoholic and control groups were matched by age, and paired t tests were performed (Fig. 1). There was no significant difference between the two groups on the UPSIT (t = -1.36, p < .25). Alcoholics scored an average of 8 4 . 5 % + 2 . 2 2 SE, while the controls scored an average of 89.3% ,+ 1.9 SE (chance being 25%). Analysis of responses to the matchto-sample test indicated a significant difference between alcoholics and their age-matched controls (t = -6.64, p < ,0005). The alcohol group scored an average of 57.6% + 2.8 SE while controls scored an average of 80% & 4.4 SE (random chance being 33%). Examination of the scores for the alcoholic group indicated high Pearson correlations between some variables: match-to-sample with years drinking was -.808, with the amount of alcohol reported consumed ,338; see Table 1.

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OLFACTORY FUNCTION IN CHRONIC ALCOHOLICS

Smell Identification

Match-to-Sample

Task

FIG.1. Percent correct and standard errors on the UPSIT and Matching-to-Sample Test for alcoholics (filled bar) and controls (open bar). Individual scores are shown For both groups (ns = 8 ) , and chance level (dotted line) of performance is indicated.

The correlation between scores on UPSIT and the match-to-sample test was .703 for the controls, while the correlation was -.400 for the alcoholic subjects. TABLE 1 PEARSON CORRELA~ON MATRIX~

1. 2. 3. 4.

O

N

VARIABLES G FORALCOHOL GROUP(n = 8 )

Age

Years Drinking

Months abstained Amount consumed 5. UPSIT Score 6 . Matching Score

.32 ,612 .597 -.394 -.lo9

-.067 -.I28 ,274 -.a08

,223 -.a23 ,203

-.231 .338

-.4

The group of patients with histories of chronic alcohol abuse did not appear to show the olfactory deficits which have been reported for Korsakoff's patients (Gregson, Free, & Abbott, 1981). Performance on the UPSIT indicates that the alcohol group detected and identified common odors as well as did their healthy age-matched peers; however, significant differences between groups were observed on the match-to-sample. Although this test uses odors as stimuli, it also involves encoding of information to describe the odors (i.e., verbal labels) and recall for comparison for choosing the correct matching choice. General cognitive deficits have been reported with chronic alcohol abuse (Williams & Skinner, 1990), so the deficit on the matching to sample may reflect a general learning and memory deficit. Matching perform-

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J. P. KESSLAK, ETAL.

ance is also of increased difficulty since the odor stimuli were uncommon and did not have readily accessible verbal labels for encoding. These results suggest that there is a dissociation between olfactory and cognitive function as a result of chronic alcohol abuse. REFERENCES

DOTY, R. L., SHAMAN, I?, & DANN,M. (1984) Development of the University of Pennsylvania Smell Identification Test: a standardized micro-encapsulated test of olfactory function. Physiological Behavior, 32, 389-502. GREGSON, R. A. M., FREE,M. L., & ABBOTT,M. W. (1981) Olfaction in Korsakoffs, alcoholics, and normals. British Journal of Clinical Psychology, 20, 3-10. KESSLAK, J. P., COTMAN, C. W., CHUI, H. C., VANDEN NOORT,S., FANG, H., PFEFFER,R., & LYNCH,G. (1988) Olfactory tests as possible probes for detecting and monitoring Alzheimer's disease. Neurobiology of Aging, 9, 1-5. SCHIFFMAN, S. S. (1983) Taste and smell in disease. New England Journal of Medicine, 308, 1275-1279, 1337-1342. WILLIAMS, C. M., & SKINNER, A. E. G. (1990) The cognitive effects of alcohol abuse. British Journal of Addiction, 85, 911-917.

Accepted September 3, 1931.

Olfactory function in chronic alcoholics.

8 patients participating in an outpatient program for chronic alcohol abuse and 8 age-matched controls were tested for olfactory function. There was a...
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