Abstract
Background Impaired manual dexterity is frequent and disabling in people with multiple sclerosis (MS). Therefore, convenient, quick, and validated tests for manual dexterity in people with MS are needed.
Objective The aim of this study was to validate the Coin Rotation Task (CRT) for examining manual dexterity in people with MS.
Design This was a cross-sectional study.
Methods A total of 101 outpatients with MS were assessed with the CRT, the Expanded Disability Status Scale (EDSS), the Scale for the Assessment and Rating of Ataxia (SARA), and the Modified Ashworth Scale (MAS); muscle strength and sensory deficits of the hands were noted. The concurrent validity and diagnostic accuracy of the CRT were determined by comparison with the 9-Hole Peg Test (9HPT). Construct validity was determined by comparison with a valid dexterity questionnaire. Multiple regression analyses were done to explore correlations of the CRT with the EDSS, SARA, MAS, muscle strength, and sensory deficits.
Results The CRT correlated significantly with the 9HPT (r=.73, P<.0001), indicating good concurrent validity. The cutoff values for the CRT relative to the 9HPT were 18.75 seconds for the dominant hand (sensitivity=81.5%, specificity=80.0%) and 19.25 seconds for the nondominant hand (sensitivity=90.3%, specificity=81.8%); these values indicated good diagnostic accuracy. Furthermore, the CRT correlated significantly with the dexterity questionnaire (r=−.49, P<.0001), indicating moderate construct validity. Multiple regression analyses revealed that the EDSS was the strongest predictor for impaired dexterity.
Limitations Most of the people examined had relapsing-remitting MS and EDSS scores of up to 7.
Conclusions This study validated the CRT as a test that can be used easily and quickly to evaluate manual dexterity in people with MS.
Multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system, causes neurological deficits such as ataxia, spasticity, paresis, sensory deficits, and apraxia.1–3 These deficits, alone or in combination, impair manual dexterity in about 3 of 4 patients with MS.3–5 Impaired manual dexterity is associated with impaired activities of daily living (ADL), decreased quality of life, loss of employment, and increased health care costs.6–10
Identifying and treating impaired manual dexterity are important for the optimal care of patients with MS. However, manual dexterity is usually not evaluated in a standardized way, and the commonly performed Expanded Disability Status Scale (EDSS) does not assess manual dexterity adequately.11 The 9-Hole Peg Test (9HPT) is a validated test that is often used in clinical trials alone or as a component of the Multiple Sclerosis Functional Composite Measure.5,12–14 However, the 9HPT and most other dexterity assessments, such as the Box and Block Test and the Action Research Arm Test, are usually not performed in the daily routine of health care practitioners because special test material and a table needed to perform these tests make them time-consuming and cumbersome. Furthermore, these tests may only partially cover the spectrum of manual dexterity because they measure mainly arm and hand functions rather than in-hand manipulation of objects (ie, fine motor dexterity).15
The Coin Rotation Task (CRT) is a quick and easily administered bedside test for measuring rapid, coordinated finger movements with a coin.3,16,17 Because of its short administration time, the CRT has the potential to increase the frequency of assessment of manual dexterity in patients with MS in the daily clinical routine of physical therapists, occupational therapists, and physicians; more frequent assessments may have a positive impact on the treatment of neurological deficits. The CRT has already been validated in patients with stroke and Parkinson disease.17–21 However, validation of the test in patients with MS is lacking. The etiology of impaired manual dexterity in patients with MS differs considerably from that in patients with Parkinson disease or stroke because of differences in the underlying pathophysiology. Multiple sclerosis is an inflammatory disease that can affect the whole brain and the spinal cord bilaterally. In contrast, Parkinson disease is a neurodegenerative disease that affects predominantly the basal ganglia, and stroke usually leads to focal and mostly unilateral brain damage. Therefore, differences in dexterous performance in patients with these diseases can be expected, and performance on the CRT in patients with one disease cannot be extrapolated to patients with another disease, especially with regard to psychometric properties and the establishment of cutoff values.
The aim of this study was to validate the CRT as a quick and convenient test for manual dexterity in people with MS. We hypothesized that the CRT would correlate significantly with the 9HPT, which is the gold standard for measuring manual dexterity in MS research, indicating good concurrent validity.5,12–15 Using the 9HPT as a reference test, we wanted to establish the diagnostic accuracy of the CRT and to determine cutoff values for the detection with the CRT of impaired manual dexterity in people with MS. Furthermore, we hypothesized that the CRT would correlate significantly with a valid dexterity questionnaire, indicating moderate construct validity.3
Method
Study Design and Participants
A total of 101 people with clinically isolated syndrome, relapsing-remitting MS, secondary progressive MS, or primary progressive MS, as determined with the 2010 McDonald criteria,22 and receiving or not receiving immunomodulatory therapy were examined at our outpatient clinic. The main exclusion criteria were relapses or steroid therapy within the preceding 2 months and additional diseases or medications that could influence test performance. Fifty-nine participants in the present study had taken part in a previous study in which the prevalence of apraxia in MS was assessed; 42 additional participants were included in the present study to evaluate construct validity and diagnostic accuracy with the 9HPT.3 Each participant provided informed consent.
Procedure
Demographic data (date of birth and sex), medical and surgical histories, dates of onset and diagnosis of MS, disease duration, number of relapses in participants with relapsing-remitting MS, and medication history were collected from all participants. Neurologic examinations, including the Kurtzke EDSS,11 were performed for all participants. Handedness was defined according to the Edinburgh Handedness Scale.23
In addition, items 5 to 7 of the Scale for the Assessment and Rating of Ataxia,24 the Modified Ashworth Scale for spasticity,25 and the Mini-Mental State Examination for cognition were performed.26 Muscle strength of the hands was rated according to the Medical Research Council Scale (M0–M5),27 and sensory functions of the hands were rated as normal or abnormal through superficial touching of the hands.
To perform the CRT, participants had to rotate a Swiss 50-centime coin (diameter=18.20 mm, thickness=1.25 mm, weight=2.2 g) as quickly as possible among their thumb, index, and middle fingers. The time to perform 20 half turns was measured.17 The CRT was performed twice with both hands, and the mean value for each hand was calculated.
To perform the 9HPT, participants were seated at a table with a shallow container holding 9 pegs and a plastic block with 9 empty holes. The participants had to put the pegs, 1 at a time, into the holes and remove them again, 1 at a time, and place them in the shallow container. The total time to complete the task was recorded. Age- and sex-adapted normal values are available.5,12–15 The 9HPT was performed twice with both hands, and the mean value for each hand was calculated.
As a dexterity questionnaire, an adapted version of a dexterity questionnaire described by Sunderland was used (eAppendix).28 It contains 24 questions about manual dexterity; the questions are divided into 5 subgroups (washing and grooming: 4 questions; dressing: 3 questions; meals and kitchen tasks: 7 questions; everyday tasks: 6 questions; and television and radio: 4 questions). For each question, participants had to state whether they had no problems (4 points), minor problems (3 points), or major problems (2 points) performing the task or needed aid (1 point) to perform the task. The points were added for each subgroup, and the subgroup scores were summed to produce a total score. The utility and validity of this questionnaire for detecting impaired dexterity in people with MS have been shown elsewhere.3
Data Analysis
Statistical analyses were performed with PASW for Windows (version 18.0, SPSS Inc, Chicago, Illinois). Concurrent validity was measured by computing the Pearson coefficient of correlation between the CRT and the 9HPT. The diagnostic accuracy (sensitivity, specificity, and predictive values) of the CRT for detecting manual dexterous impairments was determined relative to performance on the 9HPT. On the basis of performance on the 9HPT, we determined whether participants had impaired dexterous skills or not, as indicated by a binary classification display. Receiver operating characteristic curve analyses were used to define optimal cutoff values for the detection of impaired dexterity with the CRT. The area under the curve was used as a global index of the diagnostic accuracy of the CRT.29 By definition, an area under the curve of greater than 0.7 is considered indicative of good diagnostic accuracy.30 Construct validity, which is the extent to which an instrument measures the intended theoretical construct, was examined by computing the Pearson correlation between the CRT and the dexterity questionnaire.31
Further correlation analyses of other variables that may influence dexterous performance, such as age, disease duration, EDSS, ataxia, spasticity, muscle strength, and sensory deficits, were performed. For these purposes, either Pearson or Spearman correlation analyses were used, depending on the type of variable. In the next step, multiple stepwise regression analyses were used to explore the strongest predictor of performance on the CRT. The level of significance was set at P=.05 (2-tailed).
Results
Characteristics of Participants and Clinical Examinations
The characteristics of the participants are shown in Table 1, and the results of the clinical examinations are shown in Table 2. There were no relevant comorbidities. Nonsteroidal antiinflammatory drugs and antidepressants were the most common additional medical treatments. Participants with higher EDSS scores took more muscle relaxants. All but 7 participants were right-handed.
Characteristics of Participants (n=101)a
Results of Clinical Examinationsa
Significant Correlations of the CRT With the 9HPT and the Dexterity Questionnaire
The CRT correlated significantly with the 9HPT (r=.73, P<.0001) in the 42 additional participants, indicating good concurrent validity. In addition, the CRT correlated significantly with the total score on the dexterity questionnaire, indicating moderate construct validity (r=−.49, P<.0001). The subgroups meals and kitchen tasks, dressing, everyday tasks, and television and radio showed significant correlations as well, but the subgroup washing and grooming did not. When the CRT and the 9HPT were compared with the dexterity questionnaire and the EDSS, additional correlation analyses revealed that the CRT correlated better with the total score on the dexterity questionnaire than did the 9HPT (CRT: r=−.49, P<.0001; 9HPT: r=−.27, P<.08). The CRT and the 9HPT correlated almost identically with the EDSS (CRT: rho=.62, P<.0001; 9HPT: rho=.65, P<.0001).
The EDSS Was the Strongest Predictor of Performance on the CRT
There were significant correlations between the CRT and the EDSS, Scale for the Assessment and Rating of Ataxia (items 5–7), Modified Ashworth Scale, muscle strength (Medical Research Council Scale) and sensory deficit scores, age, and disease duration (Tab. 3).
Correlations of the CRT and the 9HPT With Various Examinationsa
When stepwise multiple regression analyses with CRT as the dependent variable and EDSS, disease duration, Scale for the Assessment and Rating of Ataxia (items 5–7), Modified Ashworth Scale, muscle strength and sensory deficit scores, age, and disease duration as the independent variables were used, a significant model emerged for the CRT; the EDSS was the strongest predictor of performance on the CRT (F1,99=44.73, P<.001, R2=.558).
Good Diagnostic Accuracy of the CRT
A binary classification display relative to the 9HPT showed that the diagnostic accuracy of the CRT was good, with cutoff values for the CRT of 18.75 seconds for the dominant hand and 19.25 seconds for the nondominant hand. Higher values indicated pathological CRT results and impaired manual dexterity. On the basis of these values, the specificities of the CRT were 80.0% on the dominant side and 81.8% on the nondominant side. The sensitivities were 81.5% on the dominant side and 90.3% on the nondominant side (Tab. 4). As determined with these cutoff values, 66.3% of the participants in our cohort had impaired manual dexterity (dominant hand: 50.5%; nondominant hand: 59.4%).
Specificity, Sensitivity, and Predictive Values of the CRT and the 9HPTa
The receiver operating characteristic areas under the curve for the CRT were .848 on the dominant side (Fig. 1) and .919 on the nondominant side (Fig. 2); these values indicated good diagnostic accuracy of the task for both sides.
Receiver operating characteristic (ROC) curve for the Coin Rotation Task predicting dexterous deficits relative to the 9-Hole Peg Test for the dominant hand. AUC=area under the curve.
Receiver operating characteristic (ROC) curve for the Coin Rotation Task predicting dexterous deficits relative to the 9-Hole Peg Test for the nondominant hand. AUC=area under the curve.
Discussion
The results of the present study indicated that the CRT was a valid test for the evaluation of manual dexterity and its consequences on ADL in people with MS. The CRT correlated significantly with ataxia and spasticity of the arms and with muscle strength and sensory deficits of the hands. These results were not surprising because these deficits impair manual dexterity when they occur alone or in combination. As a combined measurement of disability, the EDSS was the strongest predictor of impaired manual dexterity. This result was meaningful because it indicated that when MS progresses, dexterous performance is expected to deteriorate as well; this relationship has been shown elsewhere.32
The strong significant association between the CRT and the 9HPT indicated good concurrent validity. Furthermore, the CRT was found to be specific and sensitive when the 9HPT was used as a reference measure; these data indicated good diagnostic accuracy (Tab. 4).5,12 When the CRT with the calculated cutoff values of 18.75 and 19.25 seconds for the dominant and nondominant hands, respectively, were used, 66.3% of the participants were found to have pathological CRT results, indicating impaired manual dexterity. This percentage was similar to findings from other studies addressing the frequency of impaired manual dexterity in people with MS.4,5 The significant correlation between the CRT and the dexterity questionnaire indicated moderate construct validity. This correlation was superior to that of the 9HPT with the dexterity questionnaire; this finding may indicate that the CRT measures fine motor abnormalities not detected by the 9HPT.
Our results underlined the validity of the CRT for the evaluation of impaired manual dexterity of both the dominant hand and the nondominant hand, especially when the CRT was compared with the 9HPT, a reliable, valid, and sensitive test for detecting dexterous difficulties in people with MS.12,14,15 The 9HPT was shown by Lamers et al33 to be a good predictor of perceived arm performance in people with MS, and the results for the CRT in the present study were similar. In addition, the CRT correlated better with the dexterity questionnaire than did the 9HPT in the present study.
From a clinical perspective, these findings are of interest because the CRT is a quick and convenient dexterity test. It can be performed in various clinical settings and requires only a coin and a timer; unlike most other dexterity tests, the CRT requires no additional test material or a table.15 Therefore, it has the potential to increase the frequency of assessment of manual dexterity in people with MS.
Careful assessment of manual dexterity is relevant because impairment of manual dexterity can be associated with or even cause professional difficulties and problems in daily living.4–10 Such an assessment can enhance understanding of a patient's problems, and specific rehabilitative measures can be initiated to improve manual dexterity and, ultimately, ADL and quality of life.34,35
The CRT is predominantly a hand function test that measures rapid, precise coordinated finger movements for manipulating small objects with the fingers (fine motor dexterity). Unlike the CRT, most other validated tests, such as the 9HPT, the Box and Block Test, and the Action Research Arm Test, mostly assess arm and hand function with regard to the precision of arm movements and motor grasp and release skills of the hand.15,36 Therefore, different tests may evaluate different aspects of dexterity that have different impacts on ADL. In the present study, the CRT correlated with all subgroups of the dexterity questionnaire except for washing and grooming. This subgroup contained questions about whether participants had problems cleaning their teeth with a toothbrush, turning on a tap, shaving or applying makeup, and combing or brushing their hair. These tasks measure mainly arm and hand functions rather than in-hand manipulation of objects (ie, fine motor dexterity); this difference may explain the lack of correlation. However, the present study was not designed or adequately powered to address the predictive values of different dexterity tests for general ADL and specific dexterity-related ADL and to determine whether one test or several tests are needed to adequately evaluate manual dexterity in people with MS.
Limitations of the Study
Only people who were ambulatory and had EDSS scores of up to 7 were included in the outpatient cohort. People who were more severely disabled were not evaluated. Nevertheless, the results showed that the EDSS was the strongest predictor of impaired manual dexterity, and it is likely that this correlation continues at higher EDSS scores. Furthermore, the numbers of participants with clinically isolated syndrome and primary progressive MS in the present study were low. Therefore, the results cannot be generalized to all MS disease types. Finally, training effects as well as test-retest reliability and sensitivity to change should be assessed in future longitudinal studies to further establish the value of the CRT.
In conclusion, the results of the present study indicated that the CRT was a valid test for the evaluation of manual dexterity and its impact on ADL in people with MS; compared with the 9HPT, the CRT showed good concurrent validity, construct validity, and diagnostic accuracy. These data are clinically relevant because the CRT is quick and easy to apply, requiring only a coin and a timer. The CRT can be performed in various clinical settings and has the potential to increase the frequency of assessment of manual dexterity in people with MS. More frequent assessments can enhance understanding of a patient's problems, and specific rehabilitative measures can be initiated to improve manual dexterity and, ultimately, ADL and quality of life.
Footnotes
Dr Heldner, Dr Vanbellingen, Dr Bohlhalter, Dr Müri, and Dr Kamm provided concept/idea/research design. Dr Heldner, Dr Vanbellingen, Dr Mattle, and Dr Kamm provided writing and data analysis. Dr Heldner and Dr Kamm provided data collection and participants. Dr Heldner, Dr Bohlhalter, and Dr Kamm provided project management. Dr Mattle provided facilities/equipment. Dr Bohlhalter provided institutional liaisons. Dr Heldner, Dr Vanbellingen, Dr Bohlhalter, and Dr Müri provided consultation (including review of manuscript before submission).
This study was approved by the Ethics Committee of Kantonale Ethikkomission Bern, Bern, Switzerland.
Parts of this research were presented orally at the MS Researcher Meeting; August 23, 2013; Bern, Switzerland; as a poster for the European Committee for Treatment and Research in Multiple Sclerosis; October 2–5, 2013; Copenhagen, Denmark; and as a poster at the Day of Clinical Research; November 6, 2013; Bern, Switzerland.
- Received June 20, 2013.
- Accepted June 2, 2014.
- © 2014 American Physical Therapy Association
References
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