Most of the acute neurological effects of ethanol alcohol, such as slurred speech, ataxia, and confusion/sedation, are reversible, and the symptoms will disappear after the blood alcohol level gets down to below the intoxication level. However, in very high dose, alcohol can cause stupor or even coma, with irreversible neurological damages from associated hypoglycemia (from the hypoglycemic effect of alcohol and from concomitantly inadequate food intake) or hypoxemia (from the respiratory depression effect of alcohol). Also, there can be indirect permanent brain damage from falls, car accidents, regurgitation with aspirations, drowning, etc.
Most of the chronic neurological effects of ethanol alcohol, such as Wernicke-Kosakoff syndrome, alcoholic cerebellar degeneration, and alcoholic dementia are irreversible, and at present, there are no effective treatments to reverse neurological damage in these conditions. However, further progression can be halted by quit drinking alcohol. And, in the case of Wernicke’s encephalopathy, if adequate dose of thiamine is given in time, neurological injuries can be reversed and permanent neurological damage may not occur.
Healthline. Alcohol-Related Neurologic Disease
Wikipedia. Alcohol intoxication
Wikipedia. Wernicke-Korsakoff syndrome
Arts NJM, Walvoort SJW, Kessels RPC. Korsakoff’s syndrome: a critical review. Neuropsychiatr Dis Treat. 2017; 13: 2875–2890. doi: 10.2147/NDT.S130078
Harper C. The Neuropathology of Alcohol-Related Brain Damage. Alcohol and Alcoholism. 2009 Mar-Apr; 44(2):136–140. https://doi.org/10.1093/alcalc/agn102
Ridley NJ, Draper B, Withall A.Alcohol-related dementia: an update of the evidence. Alzheimers Res Ther. 2013; 5(1): 3. doi:10.1186/alzrt157