Reliability of hand function testing instruments in patients with muscular dystrophies

Abstract

Aims Welander distal myopathy (WDM) and myotonic dystrophy type 1 (DM1) are conditions characterized by gradually impaired hand function. Measurement of hand function is therefore important in therapy for patients. However, to date reliability of common hand function test instruments for these patients has not been evaluated. The aim of the study was to test intra-rater reliability (test-retest) of the hand function testing instruments: the Grippit®, Grip Ability Test (GAT), hand-held myometer (Microfet2TM) and Purdue Pegboard in patients with WDM and DM1. In addition, inter-rater reliability of these instruments was tested in DM1 patients. Methods For test-retest, the two patient groups (16 patients in each group) were tested on 2 consecutive weeks, on the same day of the week and at the same time of day. During the second week, the DM1 patients were randomly tested either before or after retest for inter-rater reliability. Results Mainly good–very good (intra-class correlation coefficient≥0.61) intra-rater and inter-rater reliability were found in three out of four instruments tested: the Purdue Pegboard, Grippit and the hand-held myometer for both WDM and DM1 patients. Conclusions The instruments are thus considered reliable for evaluating hand function in patients with WDM and DM1. However, the GAT and pinch grip measured with the Grippit® need to be interpreted with caution, as the reliability of these instruments varied from fair to good.

Grip force and pinch grip in an adult population: Reference values and factors associated with grip force

“…In two previously published studies of persons with neuropathy and muscular dystrophies, the authors conclude that pinch grip evaluation should be interpreted with caution (9,34). Our experience is that it is more difficult to standardize the test situation for pinch grip than for grip force, because the armrest leads to a somewhat awkward position of the wrist.…”

A review of muscle‐ and performance‐based assessment instruments in DM1

“…QMT methods have been used for evaluation of grip strength, pinch strength, neck flexion, wrist flexion, wrist extension, finger flexion, finger extension, ankle dorsiflexion, and ankle eversion. IRR values range from intraclass correlation coefficient (ICC) 0.44 for pinch force, to 0.90 for finger flexion force (Table ) . Inter‐rater reliability values range from ICC 0.12 for wrist flexion, to ICC 0.96 for ankle dorsiflexion (Table ) .…”

Functioning and disability in adults with myotonic dystrophy type 1

“…The NHPT is considered valid and reliable in various populations [21,22]. Good test-retest reliability has been reported for assessments with the Purdue Pegboard, a similar test to the NHPT, in adults with DM1 [20].…”

“…Measures of grip strength with hand dynamometers are considered to be valid and reliable [17][18][19]. High test-retest reliability was reported when Grippit 1 , another similar instrument, was used for grip strength assessments in adults with DM1 [20].…”