A new clinical test for cervicocephalic kinesthetic sensibility: "The fly"

Objective: To investigate the reliability and discriminative ability of a new test designed to detect accuracy of neck movements. Design: Repeated-measures. Case-control. Setting: University musculoskeletal research clinic in Iceland. Participants: Twenty women (mean age +/- standard deviation [SD], 30.8 +/- 9.1 y; range, 18 - 49 y) with chronic whiplash-associated disorders (WAD) grades I and II (duration, 6mo-6y), with current pain score on a visual analog scale of 46.8 +/- 21.8, and a disability score on the Northwick Park Neck Pain Disability Index of 45% +/- 14%. Twenty asymptomatic women (mean age +/- SD, 29.3 +/- 8.6y; range, 18 +/- 48y) with no history of whiplash or insidious onset neck pain served as controls. Intervention: A slowly moving object appeared on a computer screen and traced an unpredictable movement path that the subjects were required to follow by moving their heads. Three randomly ordered movement patterns were tested. Main Outcome Measure: A new software program connected to a 3Space Fastrak system was used to measure the mean absolute error (in millimeters) of 3 trials in each movement pattern. Results: The mean differences ( 2 SD) between days 1 and 2 were .01 +/- .64 mm for the asymptomatic group and .33 +/- 1.80 mm for the WAD group. The between-day intraclass correlation coefficients were between .60 and .77 for the asymptomatic group and .79 and .86 for the WAD group. Repeated-measures analysis of variance revealed a significant difference between groups (P = .02). The Tukey post hoc test showed significant between-group differences for each movement pattern (P less than or equal to .05). In each successive trial, a slight improvement for the asymptomatic group and a slight worsening for the WAD group were detected. Conclusions: Better reliability was detected for the asymptomatic group than for the WAD group. The test could discriminate between the asymptomatic group versus the chronic WAD group.