Which disease is classified as an early-onset dementia?

Amyotrophic Lateral Sclerosis (ALS) is classified as an early-onset dementia due to its potential effects on cognitive functions in individuals, particularly in cases where the disease manifests at a younger age. While ALS primarily affects motor neurons and leads to muscle weakness and atrophy, it can also be associated with cognitive decline. This cognitive aspect, referred to as frontotemporal dementia (FTD), can occur in some patients with ALS, further categorizing it within the realm of dementia disorders.

This classification is significant since ALS typically presents between the ages of 40 and 70, and its cognitive implications can drastically affect patient care and quality of life. The other diseases listed, while they have their own neurologic implications, do not primarily fall under the classification of early-onset dementia in the same way as ALS.

Multiple Sclerosis, for instance, can have cognitive effects but is not classified strictly as a dementia, while Guillain-Barre Syndrome is an acute condition affecting peripheral nerves, and Parkinson's Disease, although associated with dementia in some cases, is primarily a movement disorder rather than a condition that reflects early-onset dementia directly. Thus, ALS stands out for its unique combination of motor and potential cognitive impairment.