AUSTRALIAN ALCOHOLJDRUG REVIEW, ¥OL 2, NO. 1, JANUARY 1963

ALCOHOL-RELATEO BRAIN OAMAGE: AN HYPOTHESIS

* Kev in W a l s h

The continuum of impairment in brain dysfunction, first suggested by Ryback in 19711, has been extended to the strong possibility of two quite different aetiologies in the development of alcohol-related brain damage. While the hypothesis presented below is speculative, it is an attempt to provide a summary which can be critically examined by others.

Heavy alcohol consumption results in increasing risk of cognitive deficit, particularly of the more adaptive functions which deteriorate early.

An examination of the higher adaptive functions of the drinker at risk should form a useful 'early warning system' for brain impairment, using appropriate psychological tests. There is evidence that such deficit can be detected even in the so- called 'social drinker'.2, 3 The frequent finding of neuropatho- logical changes in the anterior parts of the brain would tend to support this contention since these regions are differentially involved in adaptive behavJour.

With increased drinking, higher levels of information- processing become increasingly involved. In our experience, heavy drinkers without a clinically apparent amnesic difficulty perform poorly on learning and memory tasks which require the subject to organize the material for the process of committing it to memory. Thus patients perform poorly on longer verbal serial learning tasks and complex maze learning. 4 Qualitative features strongly suggest that this is a 'frontal' amnesia. This allows an explanation of all the cognitive changes, namely, that they are caused by some pathological process which affects wide regions of the brain, but differentially affects the anterior regions.

This point of view is cogently expressed by Ryan & Butters. s Heavy drinkers often have difficulty with problem-solving and concept-formation tasks. Before the appearance of the amnesic syndrome, they may perform poorly on certain memory tasks for the same reason, namely because they use inappropriate strategies.S

Intellectual impairment (learning ability, concentration, and memory difficulty) has been observed in 59% of 37 young alcoholic patients aged 21-35 years (average = 30 years) with 3-17 years (median = 10 years) of excessive alcohol con- sumption. 7 In these subjects, cerebral atrophy (on computer- ized brain tomography) and cirrhosis was present in 49% and 19% of subjects, respectively.

Before or after the advent of cognitive changes some, but not all, heavy drinkers may suffer head trauma, brain anoxia and liver damage. They may develop a poor state of nutrition and suffer the added central lesions due to thiamin avitaminosis

and consequently develop the Korsakoff amnesic syndrome. The term 'Korsakoff psychosis' refers to a total clinical picture made up of the Korsakoff or general amnesic syndrome, plus the non-amnesic cognitive changes of different aetiology plus 'personality' changes. Thus, every patient with an alcoholic amnesic syndrome should, of necessity, demonstrate on testing the characteristic problem-solving difficulties as well as the amnesia. Similarly, the well-nourished alcoholic should show clear evidence of loss of problem-solving ability without the Korsakoff amnesic disorder.

The final result of prolonged heavy drinking is an alcohol- related dementia, possibly as an extention of whatever process produces the non-amnesic cognitive changes. Alcoholic dementia is often seen coupled with an extreme form of the amnesic syndrome. Cutting [1978] e considers that this acceler- ated psychological deterioration is the same in nature, but more severe in degree, as the 'subclinical psychological deterioration' mentioned above. However, it develops gradually and is relatively independent of nutritional factors. The evident intellectual decline justifies its status as separate from Korsakoff's syndrome.

R E F E R E N C E S :

1. Ryback, R. (1971), Q.J. Stud. Alcohol 32, 995-1016. 'The continuum and specificity of the effects of alcohol on memory'.

2. Parker, E.S. & Noble, E.P. (1977), J. Stud. Alcohol 38, 1224-1232. 'Alcohol consumption and cognitive func- tioning in social drinkers'.

3. Jones, M.K. & Jones B.M. (1980), J. Stud. Alcohol 41, 179--186. 'The relationship of age and drinking habits to the effects of alcohol on memory in women'.

4. Hunt, M. (1979), 'A preliminary neuropsychologJcal in- vestigation of frontal lobe disorders found in alcoholism', Unpublished Masters Thesis, University of Melbourne.

5. Ryan, C. & Butters, N (1980), Alcoholism: Clinical and Exptl. Res. 4, 190-198. 'Further evidence for a continuum of impairment encompassing male alcoholic Korsakoff patients and chronic alcoholic men'.

6. Flavell, J.H. (1971), Human Development 14, 272-278. 'First discussant's comments: What is memory deve!op- ment the development of?'

7. Lee, K., MoUer, L., Hardt, F., Haubek, A. & Jensen, E. (1979), Lancet 2, 759-761. 'Alcohol-induced brain damage and liver damage in young males'.

8. Cutting, J. (1979), Brit. J. Psychiatr. 132, 240-251. 'The relationship between Korsakoff's syndrome and alcoholic dementia'.

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* Or. Kevin Walsh, Lecturer in Psychology, University of Melbourne, Melbourne, Victoria.