1.4 Nervous-system damage
Chronic consumption of high levels of alcohol can cause irreversible damage to the nervous system. The majority of people with chronic alcoholism have some degree of dementia, which is a general loss of intellectual abilities including memory, judgement and abstract thinking, as well as personality changes. The general effect seems to be a shrinkage of brain tissue, as revealed by brain imaging techniques (Figure 6) or post-mortem studies, the extent of which correlates with the amount of alcohol consumed (National Institute on Alcohol Abuse and Alcoholism, 2000). In particular shrinkage is extensive in the prefrontal cortex, PFC, which has responsibility for choice, decision-making and regulation of behaviour. It is also present in deeper brain regions associated with memory, and in the cerebellum which is involved in movement and coordination.
Alcoholism is also associated with damage to the peripheral nerves (i.e. those connecting the central nervous system, CNS, with the rest of the body). This causes symptoms such as sensory disturbances (numbness or pain), motor disturbances (weakness and muscle wasting) and some problems with speech, swallowing, heart rate, pupil function, erectile function, breathing during sleep, etc. The mechanism of nerve damage is not clear and could be associated with a direct toxic effect of ethanol on nerves, or indirectly via nutritional deficiencies.