Our objective was to assess the association between amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases such as Alzheimer's disease (AD), frontotemporal dementia (FTD) and Parkinson's disease (PD). From May 2007 through August 2012 we investigated 146 patients with newly diagnosed ALS and 146 age- and gender-matched controls. Each individual was screened for cardinal extrapyramidal signs (neurological examination) and cognitive dysfunction (Mini Mental State Examination, MMSE and Frontal Assessment Battery, FAB). Results demonstrated that rigidity was present in 8.2% of cases and 2.1% of controls (adjusted odds ratio, adjOR 5.7; 95% CI 1.5-22.0). The corresponding percentages for bradykinesia and postural instability were, respectively, 8.2 vs. 2.7% (adjOR 4.8; 95% CI 1.4-16.5) and 2.7 vs. 9.6% (adjOR 0.3; 95% CI 0.1-0.9). FAB ≤ 13.4 was recorded in 24.8 vs. 9.6%; adjOR 2.9; 95% CI 1.5-5.7). Tremor and abnormal FAB score were predicted by an older age at onset while an abnormal FAB score was associated with cramps and family history of neurodegenerative diseases. In conclusion, our data support the notion that newly diagnosed ALS carries a higher than expected risk of extrapyramidal signs and FTD.
Keywords: Alzheimer's disease; Amyotrophic lateral sclerosis; Parkinson's disease; frontotemporal dementia; heterogeneity; population based.