Parkinsonism and motor neuron diseases: twenty-seven patients with diverse overlap syndromes.

It has long been recognized that signs of motor neuron disease (MND) may accompany clinical evidence of parkinsonism in different neurodegenerative conditions. By using the Columbia University Division of Movement Disorders database, we reviewed data from 5,500 cases of parkinsonism and recorded the presence of upper motor neuron (UMN) dysfunction, lower motor neuron (LMN) dysfunction, or both. Among the 27 patients so identified, we counted those with autonomic dysfunction, cerebellar dysfunction, or dementia. Among the 27 cases, seven had UMN signs and LMN signs as well as parkinsonism and were diagnosed with amyotrophic lateral sclerosis (ALS)-parkinsonism (Brait-Fahn disease). Three of the seven had dementia that was not deemed to be frontotemporal dementia (FTD). Six other patients had no LMN signs but had UMN signs and parkinsonism and were classified as having primary lateral sclerosis (PLS)-parkinsonism. Four patients had both UMN and LMN signs with parkinsonism as well as the characteristic dementia of FTD; they were diagnosed with FTD-parkinsonism-ALS. Seven patients had MND, parkinsonism, and autonomic or cerebellar dysfunction, a combination compatible with multiple system atrophy (MSA). Three patients had syndromes compatible with hereditary spastic paraplegia (HSP). In sum, we found that MND occurs in association with diverse parkinsonian syndromes; some are heritable, others sporadic and causes are uncertain. Having MND may be a risk factor for parkinsonism. A prospective study may elucidate this possibility.