Peripheral nerve function and lower extremity muscle power in older men.
Ward RE; Caserotti P; Faulkner K; Boudreau RM; Zivkovic S; Lee C; Goodpaster BH; Cawthon PM; Newman AB; Cauley JA; Strotmeyer ES
Arch Phys Med Rehabil 2014 Apr; 95(4):726-733
Objective: To assess whether sensorimotor peripheral nerve function is associated with muscle power in community-dwelling older men. Design: Longitudinal cohort study with 2.3+0.3 years of follow-up. Setting: One clinical site. Participants: Participants (n=372; mean age + SD, 77.2 + 5.1y; 99.5% white; body mass index, 27.9=3.7kg/m2; power, 1.88+0.6W/kg) at 1 site of the Osteoporotic Fractures in Men Study (N=5994). Interventions: Not applicable. Main Outcome Measures: A nerve function ancillary study was performed 4.6+0.4 years after baseline. Muscle power was measured using a power rig. Peronealmotor nerve conduction amplitude, distal motor latency, andmean f-wave latency were measured. Sensory nerve functionwas assessed using 10-g and 1.4-g monofilaments and sural sensory nerve conduction amplitude and distal latency. Peripheral neuropathy symptoms at the leg and feet were assessed by self-report. Results: After adjustments for age, height, and total body lean and fat mass, 1 SD lower motor (B=-.07, P<.05) and sensory amplitude (B>09, P<.05) and 1.4-g (B=-.11, P<.05) and 10-g monofilament insensitivity (B=-17, P<.05) were associated with lower muscle power/kg. Compared with the effect of age on muscle power (B per year, -.05; P<.001), this was equivalent to aging 1.4 years for motor amplitude, 1.8 years for sensory amplitude, 2.2 years for 1.4-g monofilament detection, and 3.4 years for 10-g detection. Baseline 1.4-g monofilament detection predicted a greater decline in muscle power/kg. Short-term change in nerve function was not associated with concurrent short-term change in muscle power/kg. Conclusions: Worse sensory and motor nerve function were associated with lower muscle power/kg and are likely important for impaired muscle function in older men. Monofilament sensitivity was associated with a greater decline in muscle power/kg, and screening may identify an early risk for muscle function decline in late life, which has implications for disability.
Nerve-function; Muscles; Sensory-motor-system; Force; Fall-protection; Physical-reactions; Physiology; Physiological-function; Physiological-effects; Physiological-factors; Age-groups; Humans; Men; Women;
Author Keywords: Aged; Motor neurons; Muscle weakness; Peripheral nerves; Rehabilitation; Sensory function; Sensory neurons
Elsa S. Strotmeyer, PhD, MPH, University of Pittsburgh, Dept of Epidemiology, 130 N Bellefield Ave, Rm 515, Pittsburgh, PA 15213
Archives of Physical Medicine and Rehabilitation