Does Acoustic Feedback Increase the Accuracy of Weight and Force Perception during Fine Motor Activities?

Abstract

It is known from basic research that fine motor activities linked to object handling such as grasping and lifting are almost automatised and highly adapted to the properties of manipulated objects. Object surface properties influence the grip-lift force coupling at object-digit-surface and the object weight perception. Such force-coupling relies on visual and somatosensory processes along with the internal models. Limited or affected somatosensory mechanism could lead to disturbed force efforts and deterioration in object weight perception. Present study was aimed to evaluate the strategy to strengthen the somatosensory mechanism by implementing additional sensory channel (grip force related online acoustic feedback) during a standard weight discrimination task. Participants from both young and old age judged the heaviness of objects with different shapes, compared to a reference object using the precision grip. Results showed that object shape manipulation influenced grip force and weight perception. Integration of additional sense supported the forward model by reducing sensorimotor processing time in both age groups. This indicates the facilitatory impact of multisensory integration on motor control. Moreover, it lowered the discrimination threshold of weight perception and improved the accuracy level. Contrarily, the effect of assistive acoustic feedback on grip force application and weight perception was not significant. We clearly observed the overall aging effects for weight perception and grip force application.