Reliability of the Handgrip Strength Test in Elderly Subjects With Parkinson Disease

Background: The handgrip strength test is widely used by clinicians; however, little has been investigated about its reliability when used in subjects with Parkinson disease (PD). The purpose of this study was to investigate the test-retest reliability of the handgrip strength test for subjects with PD. Methods: The PD group consisted of 15 patients, and the control group consisted of 15 healthy subjects. Each patient performed 3 pain-free maximal isometric contractions on each hand on 2 occasions, 1 week apart. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and 95% limits of agreement (LOA) were calculated. The 2-way analysis of variance (ANOVA) was conducted to determine the differences between sides and groups. Results: Test-retest reliability of measurements of grip strength was excellent for dominant (ICC = 0.97; P =. 001) and non-dominant (ICC = 0.98; P =. 001) hand of participant with PD and (ICC = 0.99; P =. 001) and (ICC = 0.99; P =. 001) respectively, of healthy group. Conclusions: The Jamar hand dynamometer had fair to excellent test-retest reliability to test grip strength in participants with PD.