Progression of falls in postmortem-confirmed Parkinsonian disorders

Although falls are known to occur in several parkinsonian disorders, such as Parkinson's disease (PD), multiple system atrophy (MSA), dementia with Lewy bodies (DLB), corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP), differences in the evolution of this feature have not been studied systematically in pathologically confirmed cases. Seventy-seven cases with pathologically confirmed parkinsonian disorders (PD: n = 11, MSA: n = 15, DLB: n = 14, CBD: n = 13, PSP: n = 24), collected up to 1994, formed the basis for a multicenter clinicopathologic study organized by the National Institute of Neurological Disorders and Stroke to improve differential diagnosis of parkinsonian disorders. In the present study, we determined the time course, that is, the duration from first symptom to onset (latency) and duration from onset to death, of recurrent falls. Furthermore, we analyzed the diagnostic validity of a predefined latency to onset of recurrent falls within 1 year of symptom onset. Significant group differences for latency, but not duration, of recurrent falls were observed. Latencies to onset of falls were short in PSP patients, intermediate in MSA, DLB, and CBD, and long in PD. Recurrent falls occurring within the first year after disease onset predicted PSP in 68% of the patients. Our study demonstrates for the first time that latency to onset, but not duration, of recurrent falls differentiates PD from other parkinsonian disorders. Whereas early falls are important for the diagnosis of PSP, the addition of other features increases its diagnostic predictive value.