The responsiveness of sensibility and strength tests in patients undergoing carpal tunnel decompression

Abstract

BackgroundSeveral clinical measures of sensory and motor function are used alongside patient-rated questionnaires to assess outcomes of carpal tunnel decompression. However there is a lack of evidence regarding which clinical tests are most responsive to clinically important change over time.MethodsIn a prospective cohort study 63 patients undergoing carpal tunnel decompression were assessed using standardised clinician-derived and patient reported outcomes before surgery, at 4 and 8 months follow up. Clinical sensory assessments included: touch threshold with monofilaments (WEST), shape-texture identification (STI™ test), static two-point discrimination (Mackinnon-Dellon Disk-Criminator) and the locognosia test. Motor assessments included: grip and tripod pinch strength using a digital grip analyser (MIE), manual muscle testing of abductor pollicis brevis and opponens pollicis using the Rotterdam Intrinsic Handheld Myometer (RIHM). The Boston Carpal Tunnel Questionnaire (BCTQ) was used as a patient rated outcome measure.ResultsRelative responsiveness at 4 months was highest for the BCTQ symptom severity scale with moderate to large effects sizes (ES = -1.43) followed by the BCTQ function scale (ES = -0.71). The WEST and STI™ were the most responsive sensory tests at 4 months showing moderate effect sizes (WEST ES = 0.55, STI ES = 0.52). Grip and pinch strength had a relatively higher responsiveness compared to thenar muscle strength but effect sizes for all motor tests were very small (ES ≤0.10) or negative indicating a decline compared to baseline in some patients.ConclusionsFor clinical assessment of sensibility touch threshold assessed by monofilaments (WEST) and tactile gnosis measured with the STI™ test are the most responsive tests and are recommended for future studies. The use of handheld myometry (RIHM) for manual muscle testing, despite more specifically targeting thenar muscles, was less responsive than grip or tripod pinch testing using the digital grip analyser (MIE). When assessing power and pinch strength the effect of other concomitant conditions such as degenerative joint disease on strength needs to be considered.

Assessment from Functional Perspectives: Using Sensorimotor Control in the Hand as an Outcome Indicator in the Surgical Treatment of Carpal Tunnel Syndrome

“…With the exception of the 2PD test, the effect sizes of the SWM, MTT and PHUA tests were moderate to large at one month post-surgery. In agreement with the results of recent research [ 22 , 34 ], SWM and tactile gnosis are more responsive tests than the 2PD test. The CTS patients had statistically significant improvements in both sensory status and sensorimotor control of the hands ( p <0.001); in contrast, the muscle strength of the pincer grip decreased after CTR ( Table 2 ).…”

“…As the high measuring consistency has been reported for the MTT [ 37 ], there is no learning effect with regard to reducing the time-requirement in this cohort study. Although the follow-up period was relatively short in the current work, the improved abilities to identify weight, shape and roughness among the CTS patients show that they had the potential to make significant progress after CTR, as seen in the findings of previous research [ 22 ]. Though the 2PD test has been routinely used clinically, a previous report has indicated its invalid to reflect the tactile spatial acuity of hands [ 38 ].…”

“…Sensibility and muscle strength tests are frequently used to analyze how well CTS patients respond to treatment [ 22 , 23 ]. However, the improvements in the delicate sensorimotor control of the hand have received relatively little attention.…”

Use of Outcome Measures in Managing Neck Pain: An International Multidisciplinary Survey

“…The low rates of pain threshold testing reflected in this survey indicate a need to translate this assessment knowledge into practice. Although the responsiveness of sensory measures to detect change has been studied in peripheral neuropathy [53-55], it is less well known whether these measures detect change in response to treatment of neck conditions suggesting the need for additional research.…”

Hypothenar fat pad flap surgery for end stage and recurrent carpal tunnel syndrome

“…The assessment of sensibility [13,14] included the touch threshold and shape-texture identification. The patient's vision was occluded with a screen during these tests.…”