The differential effect of age on upper limb sensory processing, proprioception, and motor function

Sensory processing consists in the integration and interpretation of somatosensory information. It builds upon proprioception but is a distinct function requiring complex processing by the brain over time. Currently little is known about the effect of aging on sensory processing ability or the influence of other covariates such as motor function, proprioception, or cognition. In this study, we measured upper limb passive and active sensory processing, motor function, proprioception, and cognition in 40 healthy younger adults and 54 older adults. We analyzed age differences across all measures and evaluated the influence of covariates on sensory processing through regression. Our results showed larger effect sizes for age differences in sensory processing (r = 0.38) compared with motor function (r = 0.18-0.22) and proprioception (r = 0.10-0.27) but smaller than for cognition (r = 0.56-0.63). Aside from age, we found no evidence that sensory processing performance was related to motor function or proprioception, but active sensory processing was related to cognition (β = 0.30-0.42). In conclusion, sensory processing showed an age-related decline, whereas some proprioceptive and motor abilities were preserved across age.NEW & NOTEWORTHY Sensory processing consists in the integration and interpretation of sensory information by the brain over time and can be affected by lesion while proprioception remains intact. We investigated how sensory processing can be used to reproduce and identify shapes. We showed that the effect of age on sensory processing is more pronounced than its effect on proprioception or motor function. Age and cognition are related to sensory processing, not proprioception or motor function.