Sensory and motor peripheral nerve function and longitudinal changes in quadriceps strength

Abstract

Background: Poor peripheral nerve function is common in older adults and may be a risk factor for strength decline, although this has not been assessed longitudinally.

Methods: We assessed whether sensorimotor peripheral nerve function predicts strength longitudinally in 1,830 participants (age = 76.3 ± 2.8, body mass index = 27.2 ± 4.6kg/m(2), strength = 96.3 ± 34.7 Nm, 51.0% female, 34.8% black) from the Health ABC study. Isokinetic quadriceps strength was measured semiannually over 6 years. Peroneal motor nerve conduction amplitude and velocity were recorded. Sensory nerve function was assessed with 10-g and 1.4-g monofilaments and average vibration detection threshold at the toe. Lower-extremity neuropathy symptoms were self-reported.

Results: Worse vibration detection threshold predicted 2.4% lower strength in men and worse motor amplitude and two symptoms predicted 2.5% and 8.1% lower strength, respectively, in women. Initial 10-g monofilament insensitivity predicted 14.2% lower strength and faster strength decline in women and 6.6% lower strength in men (all p < .05).

Conclusion: Poor nerve function predicted lower strength and faster strength decline. Future work should examine interventions aimed at preventing declines in strength in older adults with impaired nerve function.

Keywords: Aging; Motor neurons.; Muscle weakness; Peripheral nerve function; Sensory function; Strength.