Concurrent validity of the NK hand dexterity test

BACKGROUND AND PURPOSE: The present study evaluated the concurrent validity of the NK hand dexterity test (NKHDT) by use of three separate analyses: (1) the correlation between the NKHDT and a criterion comparator (Jebson's Hand Function Test (JHFT)); (2) the correlation between both dexterity tests and a patient-rated function questionnaire; and (3) the ability of subscales to differentiate between subjects with and without upper extremity pathology. METHOD: The study population included 40 individuals with a variety of musculoskeletal problems affecting the upper extremity and 10 individuals without any history of upper extremity problems. Both dexterity tests were administered on a single occasion according to a standard protocol. Subjects also completed a rating scale which evaluated self-care, household work, work and recreation on an 0-10-point scale. RESULTS: The validity of the NKHDT was supported in all three analyses because: (1) the correlation between the NKHDT and JHFT subtests was moderate to strong (Pearson's r = 0.47-0.87) and stronger when the objects were more similar in size; (2) both scales correlated to a similar extent with patient-rated function (Pearson's r = 0.34-0.67); and (3) all subscales were statistically different between subjects with and without upper extremity pathology (p < 0.01). CONCLUSIONS: The present study supports the use of the NKHDT as a measure of hand dexterity.