Author(s): Abraham Lieberman, Aman Deep and Thurmon Lockhart
Falls are a major risk for Parkinson disease patients (PD). We sought to understand why patients fall. In one study we followed 404 PD patients for a year, 204 of who fell at least once. We did not distinguish between single and recurrent fallers. In a second study we followed 249 different patients for a year, 205 of whom fell once and 44 fell more than once (recurrent fallers). In the first study fallers were significantly older, 72.6 + 5.8 versus 66.9 + 6.1 years, had PD significantly longer 9.3 + 3.4 versus 5.4 + 2.2 years, had significantly higher (worse) motor Movement Disorder Society (MDS) Unified Parkinson Disease Rating Scale (UPDRS) scores 29.3 + 10.9 versus 18.9 + 8.3. Fallers walked with significantly shorter steps: 0.45 + 0.09 versus 0.60 + 0.13 m. Assessing step length, a simple “bedside” test, was a useful aid in predicting who might fall. In the second study recurrent fallers had PD significantly longer, 12.6 + 7.0 versus 5.9 + 4.5 years, had significantly higher motor MDS UPDRS scores 31.2 + 12.7 versus 19.7 + 8.3 and walked with significantly shorter steps: 0.37 + 0.18 m versus 0.52 + 0.19 m. A major difference between recurrent and single fallers was an inability of recurrent fallers to stand on one leg for <3 s: 95% versus 11%, odds ratio 178 CI 95% 39.5-801.2 Single fallers who are unable to stand on one leg for <3 s are at risk for recurrent falls. The short step, we believe, is an adaptation to postural instability, inability to maintain an upright position. The inability to stand on one leg, by depriving the patient of roughly half their proprioception, is a measure of risk for falls. Parkinson disease is viewed as a motor disorder, but impaired proprioception, a sensory symptom, is a major cause of recurrent falls.
