PERIPHERAL NEUROPATHY - A TRUE RISK FACTOR FOR FALLS

Background. Several studies have recently linked peripheral nerve dysf unction in the elderly with postural instability and falls. Many cause s of peripheral neuropathy (PN) have the potential for associated como rbidities, which could themselves be the true cause of these falls. Th is study tested the hypothesis that PN is not a cause of falls but jus t a marker for a comorbidity (e.g., central nervous system dysfunction ) that is the true cause of falls in this elderly population. Methods, Twenty subjects with an electromyographically documented axonal perip heral neuropathy affecting the lower extremities were identified (PN g roup) and matched by age and sex with 20 subjects with normal lower ex tremity electrodiagnostic studies (C group). A focused history and phy sical examination designed to identify factors other than PN which mig ht cause falls was performed, and a history of falls or postural insta bility over the previous year was obtained. Results, PN was found to b e significantly associated with the self-report of falls (11/20, 55% v s 2/20, 10%; odds ratio 17.0, 95% CI = 2.5, > 100) and postural instab ility (7/9, 77% vs 0/0, 0%; odds ratio 13.0, 95% CI = 1.5, > 100) over the previous year. There was no significant difference between the tw o groups in total number of other risk factors known to be associated with falls, (23 PN group vs 18 C group). The PN group did take a signi ficantly greater number of medications known to be associated with fal ls (10 PN group vs 1 C group, p < .01), but the usage pattern among fa llers and nonfallers within the PN group suggests that medications wer e not the primary cause of the falls. The PN subjects who fell demonst rated significantly worse vibratory sense at the ankle and finger (p < .05), and significantly decreased unipedal stance time (3.1 sec vs 9. 1 sec, p < .05) than the PN subjects who did not fall. Conclusions, No associated factors or comorbidities explained the high rate of falls in elderly persons with PN, suggesting that PN is a true risk factor f or falls in the elderly. Relatively greater impairment in vibratory se nse and ability to maintain unipedal stance may identify those within the PN group who are at a higher risk for falls.