Final answer:
Wernicke-Korsakoff syndrome is the brain disorder linked to chronic alcoholism and thiamine deficiency, featuring symptoms like mental confusion and memory issues, distinguished from Parkinson's and Alzheimer's diseases which are caused by protein accumulations.
Step-by-step explanation:
The type of brain disorder that is linked to chronic alcoholism and thiamine deficiency is known as Wernicke-Korsakoff syndrome. This condition is characterized by symptoms such as mental confusion, eye movement disturbances, lack of muscle coordination, and memory problems. Thiamine deficiency can lead to serious neurological problems, including Beri-Beri and Wernicke's encephalopathy. Chronic alcoholism often leads to poor dietary habits and nutrient deficiencies, which can exacerbate the situation. Unlike Wernicke-Korsakoff syndrome, disorders such as Parkinson's disease and Alzheimer's disease involve the accumulation of toxic proteins in the brain, leading to neurodegeneration and a different set of symptoms.