The incidence of cervical problems around the world has a

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1 [ research report ] Isabel Audette, PT, FCAMT, MSc1 Jean-Pierre Dumas, PT, MSc2 Julie N. Côté, PhD3 Sophie J. De Serres, PhD 4 Validity and Between-Day Reliability of the Cervical Range of Motion (CROM) Device Journal of Orthopaedic & Sports Physical Therapy The incidence of cervical problems around the world has a considerable impact on societal health. A recent Canadian study showed that neck pain represents 14.6% of all musculoskeletal problems reported annually. 5 Among cervical problems frequently reported are ones that emerge from work or activities that involve repetitive movements and static postures such as those used when working with a computer. Other prevalent causes of cervical pain are those related to whiplash-associated disorders, t STUDY DESIGN: Clinical measurement, validity and intrarater reliability study. t OBJECTIVES: (1) To confirm the validity and assess between-day test-retest reliability of cervical spine motion measurements made with the cervical range of motion (CROM) device in flexion, extension, bilateral rotation, and bilateral side flexion; (2) to provide meaningful information to clinicians about the standard error of measurement and the minimal detectable change for the CROM device. t BACKGROUND: Range of motion is a common outcome measure used in the assessment of the cervical spine. The CROM device is one of the tools used to measure cervical range of motion in the clinical setting. However, its psychometric properties are not well established, especially for measurements taken on separate days. which are the clinical manifestations of a whiplash injury. 8,12,21 Cervical range of motion (ROM) is t METHODS: Quasi-experimental design with 1 group comparison. Twenty healthy adults (9 men and 11 women) participated in this study. Cervical range of motion was simultaneously recorded with the CROM device and the Fastrak motion analysis system for all 6 cervical movements mentioned above. The CROM device was placed on the participant s head consistent with standard clinical procedures. Two Fastrak sensors were positioned with 1 on the forehead and 1 over the spinous process of the T6 vertebra. Test-retest reliability of measurements made with the CROM device was assessed, as well as its standard error of measurement and minimal detectable change, with measures taken on 2 separate days spaced 48 hours apart. t RESULTS: Values obtained by the 2 measuring devices yielded Pearson correlation coefficients ranging between 0.93 and Test-retest reliability of measurements of cervical range of motion using the CROM was found to be good, with ICCs ranging between 0.89 and The standard errors of measurement across the 6 movements ranged from 1.6 to 2.8 and the minimal detectable changes across the 6 movements ranged from 3.6 to 6.5. t CONCLUSIONS: The measurements made with the CROM were shown to be reliable in all movement directions. J Orthop Sports Phys Ther 2010;40(5): doi: /jospt t KEY WORDS: clinical tool, MDC, neck, psychometrics, spine often used as an outcome measure in the clinical setting and is now considered a standard of practice. 4 It can be a predictive tool for acute or chronic neckpain related conditions. For example, in whiplash-associated disorders, it was found that a decrease in cervical ROM within 4 weeks posttrauma could be predictive of chronicity. 22 In patients with cervicogenic headache, cervical ROM helps discriminate between this and other types of headache such as migraine or tension headache. 29 Reduced cervical ROM is one of the main complaints from patients showing cervical dysfunction and seeking help from therapists. Cervical ROM is often taken to document baseline status and treatment effect, 11 and to readjust treatment plans as needed in physiotherapy. As cervical ROM is frequently evaluated in the clinical practice, it is important to ensure that therapists have access to an objective tool for its measure. The cervical range of motion (CROM) device is one of the tools available clinically to measure cervical ROM. The CROM device consists of a plastic frame placed on the head over the nose and the ears, secured by a Velcro strap. Two independent inclinometers, 1 in the sagittal plane and 1 in the frontal plane, are attached to the frame and indicate the position of the head with respect to the line of gravity. A third inclinometer 1 Physiotherapist, Faculty Lecturer, School of Physical and Occupational Therapy, McGill University, Montreal, Canada. 2 Physiotherapist, Assistant Professor, Department of Rehabilitation, University of Sherbrooke, Sherbrooke, Canada; CRIR Jewish Rehabilitation Hospital Site, Laval, Canada. 3 Associate Professor, Department of Kinesiology and Physical Education, McGill University, Montreal, Canada; CRIR Jewish Rehabilitation Hospital Site, Laval, Canada. 4 Research Associate, CRIR Jewish Rehabilitation Hospital Site, Laval, Canada. The protocol of this study was approved by the Ethics Committee of the rehabilitation institutions of the Centre for Interdisciplinary Research in Rehabilitation (CRIR) of Greater Montreal. We affirm that we have no financial affiliation (including research funding) or involvement with any commercial organization that has a direct financial interest in any matter included in this manuscript. Address correspondence to Dr Julie N. Côté, Department of Kinesiology and Physical Education, 475 Pine Avenue West, McGill University, Montreal, Canada, H2W 1S4. julie.cote2@mcgill.ca 318 may 2010 volume 40 number 5 journal of orthopaedic & sports physical therapy

2 Journal of Orthopaedic & Sports Physical Therapy is positioned in the horizontal plane and indicates the position of the head in rotation, with respect to a reference position. From a clinical point of view, the CROM is easy to use, requires minimal palpation to locate landmarks, can be installed quickly and can be used to test cervical ROM in all directions without changing the position of the inclinometer. Furthermore, it is an affordable tool for clinics when compared to more sophisticated motion analysis systems. For an instrument to be clinically useful, it must have acceptable validity and reliability. In the only study that reported on the validity of the CROM, measurements yielded correlation coefficients ranging from 0.89 to 0.99 in all cervical ROMs 24 when compared with the Optotrak motion analysis system. However, in that study, authors pointed to the need to confirm these results, particularly for rotation motions, because Optotrak markers were occasionally hidden by the CROM toward the end range of motion in their experiment. In other studies, the CROM was shown to be reliable, with intrarater intraclass correlation coefficients (ICCs) of 0.84 to 0.96 and interrater ICCs of 0.73 to 0.94 in all cervical ROMs. 10,14,27 However, both Youdas et al 27 and Fletcher and Bandy 10 assessed test-retest reliability using multiple measurements taken during the same experimental session, and Hole et al 14 did not report the time between measurements. Of particular relevance to the clinical setting is the reliability of an instrument in measuring a construct across different sessions to allow the assessment of true progress over time. Although validity and reliability are essential properties when ascertaining the clinical value of an instrument, these properties may not be sufficient to support clinical decisions. Indeed, clinicians would likely benefit from an estimate of the error of measure as it provides an indication of the accuracy of the measure. The standard error of measurement (SEM) determines how much a score varies with repeated measures, taking into account the within-patient variability of the score. 13 Another clinically important measurement attribute is the minimal detectable change (MDC), which is considered to be the minimal amount of change that is not likely to be due to chance variation in the measurement. The MDC thus provides information on the minimal difference needed to consider the change as being a true change. Despite a fair number of studies reporting on the reliability of the CROM device, to our knowledge, only 1 has reported the SEM and MDC for this instrument and has only done so for measurements taken during the same session. 10 In a recent review of clinimetric evaluation of cervical ROM measures, de Koning et al 6 pointed to the need to further document such estimates of agreement. The aims of the present study were (1) to confirm the validity and assess between-day test-retest reliability of measurements made with the CROM device, and (2) to provide meaningful information to clinicians about the SEM and MDC of the CROM device. METHODS Participants Twenty healthy adults, 9 men and 11 women between 23 and 71 years of age (mean SD, years), were recruited among volunteers in the surrounding community of the research center at the Jewish Rehabilitation Hospital. Subjects with cervical or thoracic conditions were excluded. The study protocol was approved by the Ethics Committee of the rehabilitation institutions of the Center for Interdisciplinary Research in Rehabilitation of Greater Montreal. Informed consent was obtained from all participants prior to the experimental procedure, and their rights were protected. Experimental Procedures Subjects were asked to sit straight on a wooden chair, with their feet flat on the floor and their hands resting on their thighs. Two straps were used to restrict movement at the shoulders and trunk, allowing movement only at the neck. Subjects were first asked to look straight ahead, then to move the head as far as possible in the direction asked by the therapist, without moving the shoulders and trunk. Cervical ROM was recorded for the 6 cervical movements: flexion, extension, right and left rotation, and right and left lateral flexion, presented in a random order. Before recording any measurement, 1 practice trial was performed in each direction to allow the subjects to get familiar with the procedure and the motions for which the range was being measured. Data Acquisition Cervical ROM was measured with a CROM device (Performance Attainment Associates, Roseville, MN) during 2 sessions, separated by 48 hours, to assess test-retest reliability of measurements and to calculate the SEM and MDC. The 2 sessions were scheduled during the same period of the day on each day (ie, morning, afternoon, or early evening). The CROM device was placed on the subject s head, and a magnetic collar, also part of the CROM device, was placed on the shoulders to take into account any rotation of the trunk (FIGURE). The collar was always in the same position with respect to the magnetic pole; the chair on which the subjects were sitting was kept in the same position for all data collection. The initial position of the head was set to neutral at the zero mark of the inclinometer for flexion, extension and both side flexions. For rotation, the dial was set at zero with the head in the neutral position. When the motion was performed in 1 direction, the final position was read and recorded for each trial. Subjects moved their heads back to the initial position once the reading was finished. Three trials were executed consecutively in each direction, and the average of the 3 trials was computed for the analysis. To further confirm the validity of the journal of orthopaedic & sports physical therapy volume 40 number 5 may

3 [ research report ] analysis. Preliminary testing demonstrated that the magnetic collar that subjects wore for the CROM measurements did not interfere with the measures taken by the Fastrak electromagnetic system. Journal of Orthopaedic & Sports Physical Therapy FIGURE. Position of the cervical range of motion (CROM) device for (A) flexion and extension range of motion (ROM) measured with the lateral dial, (B) bilateral side flexion ROM, measured with the frontal dial, and (C) bilateral rotation ROM measured with the horizontal upper dial. TABLE 1 CROM device, cervical ROM measurements were simultaneously taken with the Fastrak, a motion analysis device (Polhemus, Colchester, VT). 1,15 The Fastrak is an electromagnetic 3-dimensional system that locates the position of 2 sensors in relation to a source. The Fastrak was chosen as the gold standard of measurement for cervical ROM, as it has previously demonstrated good validity, 16,26 accuracy within 0.2, 18 and high interobserver and intraobserver reliability, with studies reporting ICCs greater than and between 0.85 to for various neck movements. The Fastrak was used simultaneously with the CROM during the first session. One sensor was positioned on the anterior part of the CROM at the level of the forehead and secured with a Velcro tape. A second sensor was placed over the T6 spinous process and Cervical Ranges of Motion* Cervical Movement Fastrak, Day 1 CROM, Day 1 CROM, Day 2 Extension (61.1, 75.0) (61.8, 76.5) (61.7, 74.8) Flexion (37.1, 49.2) (33.4, 42.4) (36.8, 44.1) Left rotation (56.5, 66.2) (55.8, 64.6) (55.9, 64.5) Right rotation (54.3, 63.4) (53.1, 62.7) (56.1, 63.6) Left lateral flexion (30.3, 39.9) (31.7, 40.9) (32.4, 41.4) Right lateral flexion (28.8, 37.6) (27.9, 36.5) (29.1, 37.4) Abbreviation: CROM, cervical range of motion device. * Values are mean SD (95% confidence interval) in degrees. fixed with double-sided tape. This location for the second sensor was selected to take into account all movement occurring in the cervical region. The source was located on a horizontal support fixed on the back of the chair. The position signals of the 2 sensors were recorded at a sampling rate of 60 Hz, and the position of 1 sensor relative to the other was computed to obtain the amplitude of the movement. A continuous recording of the 3 trials was done for each movement. A tag was inserted manually to mark the end of each trial on the data record. Maximal ROM was determined by subtracting the minimal cervical angular position from the maximal cervical angular position obtained for each trial. The average of the maximal cervical ROM for the 3 trials was obtained for each movement and used for further Statistical Analysis Pearson correlation coefficients (r) and 95% limits of agreement 2 were computed for each direction to test the concurrent validity of the CROM device relative to the Fastrak. Data collected on day 1 with both devices were used for these calculations. To determine the test-retest reliability of the CROM measurements, intraclass correlation coefficients (ICC 3,3 ) with 95% confidence intervals (CIs) were obtained from the measures taken with the CROM on day 1 and day 2. Furthermore, the SEM for each movement, as measured with the CROM, with the corresponding 95% CI was calculated using the following formula 20 : SEM = SD 1 ICC, where SD is the average of the standard deviations of the test (day 1) and retest (day 2) values. From the SEM we calculated the MDC for a 90% confidence level. This calculation was done with the following formula 23 : MDC 90 = SEM 2 (z score) 90, using the z score associated with a 90% CI, which is Pearson correlations were computed with STA- TISTICA (Statsoft Inc, Tulsa, OK). The ICCs were calculated from a recognized website: informatik/projekte/odds/icc.html. RESULTS Cervical ROM values obtained using the CROM were very similar to those obtained with the Fastrak (TABLE 1). The Pearson correlation coefficients (r) between CROM and Fastrak ROM measures were high and similar across movement directions (TABLE 2), ranging from 0.93 (flexion) to 0.98 (extension, left and right side rotation). The mean differences between the measures taken with the 2 devices were minimal, with values from 0.9 to 1.2 (except for 320 may 2010 volume 40 number 5 journal of orthopaedic & sports physical therapy

4 Journal of Orthopaedic & Sports Physical Therapy TABLE 2 flexion at 5.3 ) (TABLE 2). The limits of agreement were narrow, with ranges falling between 8 and 22. The test-retest reliability of measurements made with the CROM was verified, with ICC values for all cervical measurements ranging between 0.89 (CI: ) for flexion to 0.98 (CI: ) for extension (TABLE 2). The SEM was small for all cervical ROM directions (TABLE 2), ranging from 1.6 (right side flexion) to 2.8 (flexion). The MDC 90 values were between 3.6 (right side flexion) and 6.5 (flexion) (TABLE 2). As a whole, measures taken in right side flexion, and in flexion showed, respectively, the potentially highest and lowest meaningful reliability properties. DISCUSSION The measures taken by the CROM device for all cervical motions in the present study were very similar to the normative values reported by Youdas et al 27 for adults over a similar age range (20 to 69 years). Indeed, in this previous study, the average active cervical ROM was 67.1 in extension, 46.1 in flexion, 63.5 in right rotation, 61.3 in left rotation, 37.5 in right lateral flexion, and 36.0 in left lateral flexion. The results of our study show the good concurrent validity of the CROM device when compared to the Fastrak. Correlation coefficients were found to Measurement Properties of the CROM Device* Cervical Pearson Correlation mean Movement Coefficient (r) Difference* (LOA) icc 3,3 (95% CI) sem (95% CI) mdc 90 Extension ( 7.9, 5.7 ) 0.98 (0.95, 0.99) 2.2 (1.4, 3.5 ) 5.1 Flexion ( 5.6, 16.2 ) 0.89 (0.73, 0.96) 2.8 (1.8, 4.5 ) 6.5 Left rotation ( 3.4, 5.8 ) 0.95 (0.87, 0.98) 2.1 (1.3, 3.3 ) 4.9 Right rotation ( 2.7, 4.7 ) 0.92 (0.80, 0.97) 2.6 (1.6, 4.1 ) 6.1 Left lateral flexion ( 6.5, 4.1 ) 0.97 (0.91, 0.99) 1.8 (1.2, 2.9 ) 4.2 Right lateral flexion ( 4.4, 6.3 ) 0.97 (0.93, 0.99) 1.6 (1.0, 2.5 ) 3.6 Abbreviations: CI, confidence interval; CROM, cervical range of motion; ICC, intraclass correlation coefficient; LOA, limits of agreement; MDC 90, minimal detectable change for a 90% CI; SEM, standard error of measure. * Mean difference between the measures taken with the Fastrak and the CROM on day 1. be 0.98 for extension and bilateral rotations, 0.93 for flexion, and 0.96 to 0.97 for bilateral flexions. These were higher than the correlation values reported in the only other study 24 that assessed the validity of the CROM. We obtained somewhat higher correlation values, especially in the directions of lateral flexion and right rotation, possibly due to methodological limitations associated with movements in these directions as suggested in the study by Tousignant et al. 24 Nevertheless, both studies confirm the validity of CROM measurements. Good agreement between the 2 measures in all directions was also found from the computed mean differences and limits of agreement. The spread of scores around the zero point in the 95% limits of agreement indicates that the CROM device can appropriately be used as a substitute to a more expensive measuring device such as the Fastrak. We also show that the test-retest reliability of measurements made with the CROM is excellent, according to criteria found in Portney & Watkins, 20 with ICC values for all cervical measurements ranging between 0.89 and Similar results have been reported previously by Hole et al 14 ( ), Youdas et al 27 ( ), and Fletcher and Bandy 10 ( ), although we are the first to report test-retest reliability measures across different days. When the reliability of the measurements made with the CROM device is compared with that of more sophisticated tools used in research, like the OSI Spine Motion Analyzer (intratester ICCs, ), 19 the Zebris CMS system (intratester ICCs, ), 17 or the CA6000 Spine Motion Analyzer (intratester ICCs, ), 17 it can be inferred that the CROM device displays satisfactory ICCs. Furthermore, the CROM device has the advantages of being easy to use in a clinical setting and portable, enabling rapid measurements in the field or in a home environment. When compared to other custom, rapid cervical ROM measurement techniques, the CROM device stands out as a very good tool to be used in clinical settings to obtain more objective measures than other tools currently used, such as the visual estimation (intertester ICCs, , with error estimated between 5 and 45 ) 3 and the universal goniometer (intertester ICCs, ; intratester ICCs, ), 28 which present with lower reliability properties. Finally, compared to the standard bubble inclinometer, 14,25 the data obtained from CROM has higher level of reliability, probably due to a better standardized position on the head. The cost of the CROM is higher, but both are very simple to use in a clinical context. The use of standardized experimental procedures was very important to insure a good reliability throughout the study. The seated posture of the subjects was maintained in a constant position from the beginning of the recording procedure. Also, 1 practice trial per direction was performed before the ROM measurements. An emphasis on the instructions given to the subjects was considered important, reminding the subjects to isolate the movement of their head, without moving the shoulders and trunk. The straps were very important for the measures taken with the Fastrak to eliminate movement from the thoracic and shoulder regions. Finally, measurements with the CROM on day 1 and day 2 were taken at 48-hour intervals, always at the same time of the day so as journal of orthopaedic & sports physical therapy volume 40 number 5 may

5 [ research report ] Journal of Orthopaedic & Sports Physical Therapy to eliminate any effects resulting from variation in ROM at different times in the day. 9 These precautions should be considered when the CROM device is being used in the clinical setting to insure good reliability and validity of the measures. The SEMs and the MDCs calculated in our study were relatively low for all motions, ranging from 1.6 to 2.8 for the SEM and from 3.6 to 6.5 for the MDC. These values are slightly smaller than the ones reported in the Fletcher and Bandy study 10 (SEM, ; MDC, ), which again only represented measurements taken during the same session. Some potential sources of error in our study could be due to the fact that the CROM device has display quadrants subdivided in 2 intervals, which might have resulted in limited precision of readable ROM values. For the rotation movements measured with the CROM device, other variations might also have come from the repositioning of the quadrant as it was set back to the 0 position before each movement. Despite this, we can interpret our results as being indicative of satisfactory agreement and responsiveness, which are important ingredients for appropriate interpretability of measurements in the clinical setting. Indeed, from this information on the minimal difference needed to consider the change as being a true change, we can be confident that a change larger than 6.5 in cervical ROM in any direction will be a true change. True change should be distinguished from the minimally important change, which is related to the minimally important improvement or deterioration of a patient s condition and obtained by comparing the change in ROM following an intervention with patient self-reports of overall perceived change or questionnaires related to their conditions. 7 Thus, in clinical settings, it is recommended to use the CROM device in conjunction with other subjective and objective evaluations of the patient s overall condition to assess the outcome of an intervention. CONCLUSION The results of our study confirm the reliability of measurements made with the CROM device found in other studies but for measurements taken on separate days. Our results also demonstrated relatively low SEMs and MDCs for the CROM device in all 6 directions of movement at the cervical level. Knowing the increasing emphasis on using objective tools in clinical practice, this device can thus be recommended to measure cervical ROM for research purposes, as well as in rehabilitation settings. However, future studies that include patient groups should be conducted to further substantiate the current findings. t KEY POINTS FINDINGS: The psychometric properties of the CROM were shown to be very good for measures taken from healthy subjects, with high concurrent validity (Pearson r, ) and test-retest reliability (ICC, ). The SEMs and MDCs were 1.6 (right side flexion) to 2.8 (flexion), and 3.6 (right side flexion) to 6.5 (flexion), respectively. IMPLICATION: Clinicians may use the CROM to assess cervical ROM on separate days, while keeping in mind the values reported here when estimating the meaningfulness of measurements. CAUTION: This study only assessed healthy subjects. The small number of subjects is a further limitation of this study. references 1. 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