Defining handedness: a critical variable

Score reliability and construct validity of the Flinn Performance Screening Tool for adults with symptoms of carpal tunnel syndrome

OBJECTIVE

We investigated the psychometric properties of the Flinn Performance Screening Tool (FPST) for people referred with symptoms of carpal tunnel syndrome (CTS).

METHOD

An occupational therapist collected data from 46 participants who completed the Functional Status Scale (FSS) and FPST after the participants' nerve conduction velocity study to test convergent and contrasted-group validity.

RESULTS

Seventy-four percent of the participants had abnormal nerve conduction studies. Cronbach's α coefficients for subscale and total scores of the FPST ranged from .96 to .98. Intrarater reliability for six shared items of the FSS and the FPST was supported by high agreement (71%) and a fair κ statistic (.36). Strong to moderate positive relationships were found between the FSS and FPST scores. Functional status differed significantly among severe, mild, and negative CTS severity groups.

CONCLUSION

The FPST shows adequate psychometric properties as a client-centered screening tool for occupational performance of people referred for symptoms of CTS.

Development of the Hand Active Sensation Test: reliability and validity

OBJECTIVE

To develop and establish the reliability and validity of a new quantitative functional measure of haptic perception in the hand, the Hand Active Sensation Test (HASTe).

DESIGN

Reliability was assessed by test-retest sessions. Validity was assessed via discriminant analysis, concurrent validity with 2-point discrimination and wrist position test, and receiver operating characteristic (ROC) curve construction.

SETTING

Subject preference.

PARTICIPANTS

Heterogeneous sample of 28 stroke survivors and 28 individually matched controls.

INTERVENTION

Subjects used 1 hand to manipulate HASTe objects that vary by weight or texture to complete 18 match-to-sample trials.

MAIN OUTCOME MEASURES

Two-point discrimination threshold, Wrist Position Sense Test (WPST) average error, and HASTe accuracy score.

RESULTS

Test-retest reliability was strong (intraclass correlation coefficient model 3,1 = .77). The HASTe score significantly discriminated the groups (t = 8.3, P < .001) and correlated with 2-point discrimination (r = -.67, P < .001) and WPST (r = -.60, P < .001). ROC curve area was .94 for test 1 and .92 for the average of 2 tests.

CONCLUSIONS

The HASTe is a reliable and valid functional measure of haptic perception, appears to detect impairment of haptic perception even in stroke survivors with no reported sensory deficits, and may provide valuable quantitative clinical data about complex sensory loss and hand function after stroke.

Individual finger strength: are the ulnar digits "powerful"?

This study determined the test-retest reliability of a grip device that measures the contribution of individual fingers to grip strength and described the pattern of contribution in subjects without hand pathology. Subjects repeated a set of three maximal grip efforts on two occasions separated by two to seven days. Intraclass correlation reliability coefficients were high (>0.75) for eight out of ten strength measures. The percentage contributions of the index, middle, ring, and small fingers to grip were approximately 25%, 35%, 25%, and 14%, respectively. Grip and finger strengths were highly correlated. Anthropometric measures of body size or finger length were moderately correlated with strength measures. These data suggest that there is a predictable pattern by which individual fingers contribute to overall grip strength, which is partially related to body size. The ulnar side of the hand contributes to the smaller proportion of overall grip (approximately 60% radial, 40% ulnar). The clinical utility of finger strength measures should be explored.

Measuring grip strength in normal adults: reference ranges and a comparison of electronic and hydraulic instruments

PURPOSE

To determine reference ranges for peak, average, and final adult grip strength over 10 seconds by using an electronic dynamometer, and to compare results from hydraulic and electronic dynamometers.

METHODS

The hand-grip strengths of 476 healthy adult subjects were tested using the electronic (Grippit; AB Detektor, Goteborg, Sweden) and hydraulic (Jamar; Smith and Nephew, Memphis, TN) dynamometers.

RESULTS

Age- and gender-specific reference ranges for the Jamar and Grippit dynamometers are presented. Bland-Altman analysis of the differences between the results obtained using the 2 instruments revealed a bias (mean difference) of 22 N (Jamar - Grippit) and limits of agreement of -86 to 129 N (mean +/- 2 SD), which indicates that grip measurements may vary by up to 215 N between instruments.

CONCLUSIONS

The study yielded population reference ranges of peak, average, and final strength over a 10-second grip assessment using an electronic dynamometer. Results from the Grippit and Jamar dynamometers are similar; however, the dynamometers cannot be interchanged. The Grippit provides information about endurance and fatigue of grip over 10 seconds, showing differences between right- and left-dominant adults.