Assessing grip strength in healthy individuals and patients with immune-mediated polyneuropathies

Grip strength reference values for a portable dynamometer, the hand-held Vi gorimeter, were calculated, and its validity, reliability, and responsivene ss were examined in patients with immune-mediated polyneuropathies. We stud ied 530 healthy controls (age 5-93 years), 113 patients with stable polyneu ropathy (83 with Guillain-Barre syndrome [GBS], 22 with chronic inflammator y demyelinating polyneuropathy [CIDP], and 8 with a gammopathy-associated p olyneuropathy), and 20 patients with GBS or CIDP and changing clinical cond itions (longitudinal group). An arm-disability scale was also assessed. Gri p-strength reference values were calculated depending primarily on age and gender. Significant association was obtained between the Vigorimeter and th e arm scale tin stable group, Spearman rank: r = -0.52 to -0.62; P less tha n or equal to 0.0005; in longitudinal group, linear regressions: r = 0.62-0 .64, P < 0.0001). Good interobserver and intraobserver agreements (analysis of variance, r = 0.95-0.97) and high responsiveness (standardized response mean scores greater than or equal to 0.8) were demonstrated for the Vigori meter. These results emphasize the clinical usefulness of the Vigorimeter, particularly in patients with immune-mediated polyneuropathies, (C) 2000 Jo hn Wiley & Sons, Inc.