Sudarshan Dayanidhi1, Francisco J Valero-Cuevas2. 1. Division of Biokinesiology and Physical Therapy and. 2. Division of Biokinesiology and Physical Therapy and Department of Biomedical Engineering, The University of Southern California, Los Angeles, California. valero@usc.edu.
Abstract
BACKGROUND: The ability to dynamically control fingertip force vector magnitude and direction is critical for dexterous manipulation. We quantified the dynamic control of fingertip forces to examine how dexterous manipulation declines with age. METHODS: The strength-dexterity (SD) test measures fingertip forces during compression of a slender spring prone to instability and buckling. The greatest sustained compression (designed to be under 3 N), and force dynamics therein, have been shown to be simple and quick measures of dynamic dexterous manipulation ability. We measured pinch strength and strength-dexterity test in a cross-sectional population of 98 people from 18 to 89 years of age. RESULTS: Dexterous manipulation ability is poorer at older ages, beginning in middle age (p < .001), with greater decline past 65 years of age. Fingertip force dynamics during spring compression and stabilization show a deterioration of neuromuscular control with age. Importantly, this novel detection of decline in dynamic manipulation ability is not correlated with, and thus cannot be entirely explained by, the known decline in pinch strength. We also measured standardized tests of dexterity in participants older than 45, and discuss how the strength-dexterity test uniquely captures features of sensorimotor capabilities for dexterous manipulation in this adult population. CONCLUSIONS: Starting in middle age, changes in the functional interactions among sensory, motor, and neural capabilities result in measurably poorer dynamic dexterous manipulation. This deterioration of neuromuscular control motivates and enables future studies to understand the physiological bases for this functional decline so critical to activities of daily living and quality of life.
BACKGROUND: The ability to dynamically control fingertip force vector magnitude and direction is critical for dexterous manipulation. We quantified the dynamic control of fingertip forces to examine how dexterous manipulation declines with age. METHODS: The strength-dexterity (SD) test measures fingertip forces during compression of a slender spring prone to instability and buckling. The greatest sustained compression (designed to be under 3 N), and force dynamics therein, have been shown to be simple and quick measures of dynamic dexterous manipulation ability. We measured pinch strength and strength-dexterity test in a cross-sectional population of 98 people from 18 to 89 years of age. RESULTS: Dexterous manipulation ability is poorer at older ages, beginning in middle age (p < .001), with greater decline past 65 years of age. Fingertip force dynamics during spring compression and stabilization show a deterioration of neuromuscular control with age. Importantly, this novel detection of decline in dynamic manipulation ability is not correlated with, and thus cannot be entirely explained by, the known decline in pinch strength. We also measured standardized tests of dexterity in participants older than 45, and discuss how the strength-dexterity test uniquely captures features of sensorimotor capabilities for dexterous manipulation in this adult population. CONCLUSIONS: Starting in middle age, changes in the functional interactions among sensory, motor, and neural capabilities result in measurably poorer dynamic dexterous manipulation. This deterioration of neuromuscular control motivates and enables future studies to understand the physiological bases for this functional decline so critical to activities of daily living and quality of life.
Authors: Linda Holmström; Orjan de Manzano; Brigitte Vollmer; Lea Forsman; Francisco J Valero-Cuevas; Fredrik Ullén; Hans Forssberg Journal: Exp Brain Res Date: 2011-10-25 Impact factor: 1.972
Authors: B S Lange; P Requejo; S M Flynn; A A Rizzo; F J Valero-Cuevas; L Baker; C Winstein Journal: Phys Med Rehabil Clin N Am Date: 2010-05 Impact factor: 1.784
Authors: Brigitte Vollmer; Linda Holmström; Lea Forsman; Lena Krumlinde-Sundholm; Francisco J Valero-Cuevas; Hans Forssberg; Fredrik Ullén Journal: Dev Med Child Neurol Date: 2010-05-24 Impact factor: 5.449
Authors: Nina Lightdale-Miric; Nicole M Mueske; Emily L Lawrence; Jennifer Loiselle; Jamie Berggren; Sudarshan Dayanidhi; Milan Stevanovic; Francisco J Valero-Cuevas; Tishya A L Wren Journal: J Hand Ther Date: 2014-12-04 Impact factor: 1.950
Authors: Nina Lightdale-Miric; Nicole M Mueske; Sudarshan Dayanidhi; Jennifer Loiselle; Jamie Berggren; Emily L Lawrence; Milan Stevanovic; Francisco J Valero-Cuevas; Tishya A L Wren Journal: Gait Posture Date: 2014-08-30 Impact factor: 2.840
Authors: Anna Margherita Castronovo; Natalie Mrachacz-Kersting; Andrew James Thomas Stevenson; Ales Holobar; Roger Maro Enoka; Dario Farina Journal: J Neurophysiol Date: 2018-07-05 Impact factor: 2.714