A clinical test to assess isometric cervical strength in chronic whiplash associated disorder (WAD): a reliability study.

BACKGROUND: Cervical spine muscle weakness is well demonstrated in individuals with chronic neck pain. There is a lack of literature evaluating clinically applicable means of assessing isometric cervical strength in chronic whiplash associated disorder (WAD). This study assessed the reliability of self-resisted isometric cervical strength testing using a handheld dynamometer. The relationship between strength and neck pain-related disability and kinesiophobia was also investigated. METHODS: Twenty subjects with chronic WAD performed maximum-effort isometric cervical flexion, extension, side flexion, and rotation against a hand held dynamometer. The dynamometer was held by the subject, who provided self-resistance. Subjects completed two sessions of testing on one day with two different examiners, and one session on a subsequent day with one of the original examiners. Subjects completed the Neck Disability Index (NDI) and Tampa Scale for Kinesiophobia (TSK) prior to the first testing session. RESULTS: Intraclass correlation coefficients (ICC) for directional strength measures were fair to high (0.71-0.88 for intra-rater and 0.79-0.91 for inter-rater). Total strength (sum of all directional strengths) ICCs were high for both intra-rater (ICC = 0.91) and inter-rater (ICC = 0.94) measures. All statistical tests for ICCs demonstrated significance (α < 0.05). Agreement was assessed using Bland Altman (BA) analysis with 95% limits of agreement. BA analysis demonstrated difference scores between the two testing sessions that ranged from 3.0-17.3% and 4.5-28.5% of the mean score for intra and inter-rater measures, respectively. Most measures did not meet the a priori standard for agreement. A moderate to good inverse relationship was demonstrated between kinesiophobia (TSK score) and six out of seven strength measures (α < .05). No significant correlation was found between neck disability (NDI) and cervical strength in any direction. CONCLUSION: This study demonstrated fair to high reliability of self resisted isometric cervical strength testing in the chronic WAD population. All directional strength measures except flexion demonstrated a significant inverse relationship with kinesiophobia. No cervical strength measures were correlated with neck disability. These results support testing cervical strength in this manner to reliably assess change over time within individual patients. The value of such measurement requires further consideration given the lack of correlation between cervical strength and disability. Further research is required to establish normative values and enhance clinical utility.

Minimizing the source of nociception and its concurrent effect on sensory hypersensitivity: an exploratory study in chronic whiplash patients.

BACKGROUND: The cervical zygapophyseal joints may be a primary source of pain in up to 60% of individuals with chronic whiplash associated disorders (WAD) and may be a contributing factor for peripheral and centrally mediated pain (sensory hypersensitivity). Sensory hypersensitivity has been associated with a poor prognosis. The purpose of the study was to determine if there is a change in measures indicative of sensory hypersensitivity in patients with chronic WAD grade II following a medial branch block (MBB) procedure in the cervical spine. METHODS: Measures of sensory hypersensitivity were taken via quantitative sensory testing (QST) consisting of pressure pain thresholds (PPT's) and cold pain thresholds (CPT's). In patients with chronic WAD (n = 18), the measures were taken at three sites bilaterally, pre- and post- MBB. Reduced pain thresholds at remote sites have been considered an indicator of central hypersensitivity. A healthy age and gender matched comparison group (n = 18) was measured at baseline. An independent t-test was applied to determine if there were any significant differences between the WAD and normative comparison groups at baseline with respect to cold pain and pressure pain thresholds. A dependent t-test was used to determine whether there were any significant differences between the pre and post intervention cold pain and pressure pain thresholds in the patients with chronic WAD. RESULTS: At baseline, PPT's were decreased at all three sites in the WAD group (p < 0.001). Cold pain thresholds were increased in the cervical spine in the WAD group (p < 0.001). Post-MBB, the WAD group showed significant increases in PPT's at all sites (p < 0.05), and significant decreases in CPT's at the cervical spine (p < 0.001). CONCLUSIONS: The patients with chronic WAD showed evidence of widespread sensory hypersensitivity to mechanical and thermal stimuli. The WAD group revealed decreased sensory hypersensitivity following a decrease in their primary source of pain stemming from the cervical zygapophyseal joints.

Reliability of a clinical test for deep cervical flexor endurance.

OBJECTIVE: Endurance deficiencies of the deep cervical flexors are associated with pain, increased lordosis, and headache. A need exists for reliable clinical tests of flexor endurance. This study determined intrarater and interrater reliability of such a test in persons without neck pain. METHODS: Twenty-seven subjects (aged 20-35 years) without a history of neck pain or injury were tested. Supine subjects were timed in maintaining a position involving two components: (1) craniovertebral flexion (chin tuck) and (2) lower cervical flexion (holding the occiput at a fixed height). Each subject was examined twice by 3 different examiners with 1 to 2 days between trials. RESULTS: When two values were averaged, interrater reliability for the 3 testers was 0.83, 0.85, and 0.88. Intrarater reliability values were 0.78 and 0.85 for tests 1 and 2, respectively. CONCLUSIONS: The flexor endurance test showed good intertester and intratester reliability when two values were averaged and, thus, may represent a useful clinical tool for practitioners involved in treating and preventing neck pain.