An Outcome Measure of Functionality and Quality of Life in Patients With Cervical Myelopathy

Background: Cervical spondylotic myelopathy (CSM) is a common cause of significant clinical morbidity. The Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) is a measure of health-related quality of life in these patients. Objectives: This study aimed to cross-culturally translate and validate the JOACMEQ in Iran. Patients and Methods: This study was a prospective clinical validation one. Forward-backward procedure was applied to translate the questionnaire from English into Persian. The translation and cross-cultural adaptation were performed in accordance with the published guidelines. A sample of patients with CSM was asked to respond to the questionnaire at two times: providing preoperative and postoperative assessments (6 months follow-up). To test the reliability, the internal consistency was assessed by Cronbach α coefficient and the validity was assessed by convergent validity. Responsiveness to change was also assessed comparing patients’ preoperative and postoperative scores. Results: All 87 patients completed the questionnaire. The Cronbach α coefficient for the JOACMEQ at preoperative and postoperative assessments ranged from 0.71 to 0.82 indicating a good internal consistency for the questionnaire. In addition, the correlation of each item with its hypothesized subscale of the JOACMEQ showed satisfactory results suggesting that the items had a substantial association with their own subscales. Further analysis also indicated that the questionnaire was responsive to change (P < 0.001). Conclusions: In general, the findings suggest that the Persian version of the JOACMEQ is a reliable and valid measure of functionality and quality of life evaluation among Iranian patients suffered from CSM.


Background
Cervical spondylotic myelopathy (CSM) is a progressive degenerative disease of the cervical spine. It is usually a chronic and progressive disease. As people grow older, the prevalence of CSM increases (1). Thus, the assessment of functionality and pain in those who suffer from this disease is an important part of clinical practice. As such, the Japanese Orthopedic Association scoring system (JOA score) is a well-known instrument to assess functionality in this population. The JOA score was first established by a committee of the JOA chaired for assessment of cervical myelopathy (2)(3)(4). The JOA revised the JOA score for cervical spondylotic myelopathy and developed a new disease-specific, patient-oriented outcome measure. The Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) has been validated as an outcome measure in these patients (5)(6)(7)(8)(9) and was used by Japanese investigators (10-12).

Objectives
The aim of this study was to translate the JOACMEQ into Persian, and then to use and validate the questionnaire in studies of functionality and quality of life in CSM affected patients in Iran.

Questionnaire
The Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) is a revised version of the Japanese Orthopedic Association score (JOA). It was developed for the purpose of evaluating cervical myelopathy disorders (5)(6)(7)(8)(9). It is a self-administered, disease-specific tool and contains 24 items subdivided into five subscales: lower extremity function (5 items), quality of life (8 items), cervical spine function (4 items), bladder function (4 items), and upper extremity function (5 items). The score for each subscale ranges from 0 to 100 and higher scores indicate better conditions (7,13). A user's guide and scoring manual for the JOACMEQ are available (13).

Translation
The 'forward-backward' procedure was applied to translate the JOACMEQ from English into Persian. Two general practitioners translated the questionnaire into Persian, and then the translated text was translated backward into English by a health professional and a professional translator. After a careful review, cultural adaptation, and few changes, a provisional Persian version of the questionnaire was provided.
The provisional version was tested on a number of patients in order to establish that patients could understand this version and that the questions measure what they are intended to measure. Most patients correctly understood the questionnaire. Their general comments about the difficulty of completing the questionnaire or understanding the texts were asked, and after a consensus by authors, the final version was developed.

Patients and Data Collection
A cross-sectional study was conducted and the final draft of the Persian version of the JOACMEQ was administered to a convenient sample of newly diagnosed CSM patients attending the neurosurgery clinic of a large teaching hospital in Tehran, Iran during May 2008 to November 2011. There were no restrictions on patient selection with regard to types of CSM, age or other characteristics. The exclusion criteria were prior cervical spine surgery and spinal anomalies.
It was estimated that a sample of 72 patients (at least 3 patients per item) would be enough to carry out psychometric tests as recommended (14). A trained neurosurgery resident collected the data during one complete calendar year. Patients were assessed at two points in time: preoperative and postoperative (6 months follow-up).

Reliability
to test the reliability, the internal consistency of the questionnaire was measured using Cronbach α coefficient and α ≥ 0.70 was considered satisfactory (14).

Validity
Validity was assessed performing item-scale correlations. Correlations were calculated using Pearson's correlation coefficient (r). It was expected that item scores would correlate higher with its own hypothesized scale than other scales. Correlation values of 0.40 or above were considered satisfactory (r ≥ 0.81-1.0 as excellent, 0.61-0.80 very good, 0.41-0.60 good, 0.21-0.40 fair and 0.20 poor) (14).

Responsiveness to Change
Responsiveness as a psychometric property of the questionnaire was also assessed. As such, patients' preoperative and postoperative scores were compared using the paired t-test to examine whether JOACMEQ could capture the change after the intervention (surgery).

Ethics
The Ethics Committee of Shahid Beheshti University of Medical Sciences approved the study (dated 05.2008-565523). All patients gave their informed consent after receiving both written and oral information about the project.

Results
A total of 96 patients were enrolled in the study. Of them, 87 patients completed the questionnaire and 9 patients were excluded due to prior cervical spine surgery or spinal anomalies. Table 1 shows the characteristics of the CSM patients and their scores on the JOACMEQ. The mean age of patients was 50.3 (SD = ± 10.2) years; most were married (73.6%), and had completed primary or secondary education (69.0%).
The internal consistency of the JOACMEQ as measured by the Cronbach α coefficient ranged from 0.72 to 0.80 at preoperative assessment and from 0.71 to 0.82 at postoperative evaluation indicating a satisfactory result. Table 2 presents the results.
Validity of the JOACMEQ was examined using item-scale correlations. Table 3 presents the item-scale correlation matrix between each item and the five subscales of the JOACMEQ. All correlations between items and their hypothesized scales showed satisfactory results suggesting that the items had a substantial association with their own subscale. Pearson correlation coefficient exceeded the recommended level (r ≥ 0.40) ranging from 0.49 (Q2-4) to 0.80 (Q1-8). Responsiveness to change was assessed by paired t-test. In all instances, the JOACMEQ could detect changes after the intervention (surgery) indicating improvements in all subscales as expected. Table  4 shows the results.

Discussion
The results of the present study showed that the Persian version of the JOACMEQ is a reliable measure to evaluate functionality and quality of life in Persian-speaking patients with cervical myelopathy. As noted by its authors the JOACMEQ measures five factors and the score for each factor should be interpreted independently. The total score for the JOACMEQ was considered meaningless (7, 13).     The Cronbach α for the Persian version of the JOACMEQ exceeded the recommended threshold suggesting that the Persian version of the questionnaire has satisfactory internal consistency. However, our approach for testing reliability of the JOACMEQ was different from the pioneering designers of the questionnaire. According to their report, each patient was interviewed twice at an interval of 4 weeks and then, the reliability of the questionnaire was evaluated by determining the extension of the weighted kappa coefficient. They reported that the weighted kappa was more than 0.50 for all but one item, which was 0.49 (7).
To the best of authors' knowledge, the Persian version of the JOACMEQ is the only condition-specific outcome measure for patients with CSM that was undergone psychometric evaluation in Iran. In addition, as far as we know, this research is the first attempt in the literature for translating and validating the JOACMEQ.
According to our results, this instrument seems to be a reliable and valid outcome measure for functionality and quality of life in patients with cervical myelopathy in Iran, and perhaps it could be validated in other languages to compare the results of possible upcoming studies. The JOACMEQ offers an effective method of evaluation for quality of life (12) and as suggested it is likely that the JOACMEQ succeeds and becomes a global standard to evaluate outcomes in patients with cervical myelopathy (6). We carried out a number of limited tests to perform this validation study. In future, it might be necessary to perform other tests to establish stronger psychometric indexes for the JOACMEQ. Perhaps one might argue why the authors did not perform explanatory factor analysis (EFA) and confirmatory factor analysis (CFA) to ensure that the questionnaire fits to the data.
In response, we should indicate that the questionnaire and its scoring procedure does not allow performing such analyses. For instance, there are items that should be included in different subscales. In addition, when calculating scores for subscales, all items should be multiplied by a given number. The scoring manual could be found in Appendix 1. Finally, we state that even the designers of the questionnaire did not perform any of the above analyses.
The findings from this preliminary validation study indicate that the Persian version of the JOACMEQ is a reli-able and valid instrument for measuring functionality and quality of life in patients with cervical myelopathy.