Hindawi Publishing Corporation Rehabilitation Research and Practice Volume 2012, Article ID 570387, 13 pages doi:10.1155/2012/570387 Clinical Study Effectiveness of the Gaze Direction Recognition Task for Chronic Neck Pain and Cervical Range of Motion: A Randomized Controlled Pilot Study Satoshi Nobusako,1, 2 Atsushi Matsuo,3 and Shu Morioka1, 3 1 Department of Neurorehabilitation, Graduate School of Health Sciences, Kio University, 4-2-2 Umami-naka, Koryo-cho, Kitakatsuragi-gun, Nara 635-0832, Japan 2 Department of Rehabilitation, Higashi Osaka Yamaji Hospital, 1-7-5 Inaba, Osaka, Higashiosaka 578-0925, Japan 3 Department of Physical Therapy, Faculty of Health Science, Kio University, 4-2-2 Umami-naka, Koryo-cho, Kitakatsuragi-gun, Nara 635-0832, Japan Correspondence should be addressed to Satoshi Nobusako, [email protected] Received 14 November 2011; Accepted 26 January 2012 Academic Editor: K. S. Sunnerhagen Copyright © 2012 Satoshi Nobusako et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We developed a mental task with gaze direction recognition (GDR) by which subjects observed neck rotation of another individual from behind and attempted to recognize the direction of gaze. A randomized controlled trial was performed in test (n = 9) and control (n = 8) groups of subjects with chronic neck pain undergoing physical therapy either with or without the GDR task carried out over 12 sessions during a three-week period. Primary outcome measures were defined as the active range of motion and pain on rotation of the neck. Secondary outcome measures were reaction time (RT) and response accuracy in the GDR task group. ANOVA indicated a main effect for task session and group, and interaction of session. Post hoc testing showed that the GDR task group exhibited a significant simple main effect upon session, and significant sequential improvement of neck motion and relief of neck pain. Rapid effectiveness was significant in both groups. The GDR task group had a significant session-to-session reduction of RTs in correct responses. In conclusion, the GDR task we developed provides a promising rehabilitation measure for chronic neck pain. 1. Introduction conflict between sensory-motor cortical processing networks [10, 11]. A cortical model of long-term pain implicated Chronic neck pain lasts longer than six months and is caused the neural consequences of incongruence between sensory by cervical spondylosis deformans, cervical intervertebral and visuomotor feedback, or prolonged visuosensory-motor disc displacement, or cervical sprain. Conventional therapies conflict [11]. Therapeutic measures such as mirror therapy, include thermotherapy, electric stimulation, and cervical motor imagery programming, and virtual visual feedback traction [1] and involve soft tissues/joints in the neck in aim to overcome sensory-motor incongruence and alleviate order to alter viscoelastic properties of relevant muscles [2], chronic limb pain. Phantom limb pain was hypothesized increase blood flow [3], and separate facet joints [4]. These to be due to conflict between motor intension and visual- modalities have been evaluated [5–7], but their efficacies sensory experience in the central nervous system [12]. remain unclear [8]. McCabe et al. examined mirror visual feedback for the There is increasing evidence that chronic pain prob- treatment of complex regional pain syndrome type 1 and lems are characterised by alterations in brain structure reported reduced limb pain when initiated as early as eight andfunction[9]. The pathological mechanism underlying weeks after disease onset [13]. Moseley et al. hypothesized the prolongation of peripheral pain is thought to involve that preceding mirror therapy with the activation of cortical 2 Rehabilitation Research and Practice networks without limb movement would reduce pain and given, and the active range of motion and the degree of pain swelling and introduced graded motor imagery to reduce upon neck rotation in each subject. chronic limb pain and disability in patients with complex All 17 subjects were allocated to two groups according to regional pain syndrome type 1 and phantom limb pain a computer-generated random number. The gaze direction [14, 15]. Other studies indicated that visual illusion reduced recognition task group (GDR task group, n = 9) underwent neuropathic pain in paraplegia [16] and that virtual visual physical therapy and GDR task sessions as described below. A feedback, and simulated motion, alleviated both phantom control group (n = 8) received physical therapy but did not limb pain [17] and complex regional pain syndrome [18]. undergo the GDR task. A number of mirror therapy pilot studies have addressed Primary outcome measures included active range of phantomlimbpain[19] and complex regional pain syn- motion and cervical pain, as measured by a 100 mm visual drome [20, 21]. Promising treatment avenues to alleviate analog scale, upon right and left rotation of the neck. Sec- chronic pain associated with phantom limb and complex ondary outcome measures in the GDR task group included regional pain syndrome include mirror therapy, graded reaction time and the accuracy of responses in the GDR task. motor imagery, and training with virtual visual feedback, A single session involving an interventional procedure based on the notion that chronic pain is caused by conflict was carried out as follows. After a routine physical check- between visual feedback and proprioceptive representation up, carried out by a physician, all subjects were evaluated for of the damaged limb and that mental practice modalities the active range of motion and cervical pain upon rotation improve sensory-motor incongruence to activate cortical of the neck. Thereafter, subjects were administered physical networks that subserve the affected limb. These measures therapies. Subsequent to this, the GDR task group, but not were effective for chronic limb pain but not neck pain. the control group, underwent a GDR task. Finally, all subjects Neck motion plays an important role in frequent in the two groups were assessed for active range of neck alterations of gaze direction and is normally achieved by motion and evaluated for pain on neck rotation. coordinated eye and neck movement. According to the A total of 11 interventional sessions were performed over concept of sensory-motor conflict, prolonged neck pain a total period of three weeks. A followup assessment was can be attributed to incongruence between sensory and carried out 15 days after the last session. motor feedback in the neck, and to visual-motor conflict Physical therapies were managed by two physical thera- in the relevant cortical network areas generated by gaze pists unaware of which subject group they were assessing. direction. It is thus possible that a task to overcome sensory- The active ranges of neck motion and cervical pain upon motor incongruence on the alteration of visual direction rotation of the neck were assessed independently by the may alleviate chronic neck pain. Here, we developed a experimenter, the experimenter’s assistant, and the response gaze direction recognition (GDR) task in which the subject recorder, all unaware of which subject group they were observed rotation of the neck made by another individual assessing. and attempted to recognize gaze direction with reference to This study was approved by the ethics committee of the neck motion. Moujin-kai medical corporation (approval number: H22- 12) and Kio University Health Science Graduate School 2. Methods (approval number: H19-12). 2.1. Study Design and Subjects. A pilot randomized con- 2.2. Gaze Direction Recognition Task. We developed a task trolled study was designed to test whether a newly developed for gaze direction recognition (GDR) in which the subject gaze direction recognition task could be of potential interest was asked to view an experimenter from behind, to observe in the treatment of chronic neck pain. One hundred and the rotation of the experimenter’s neck associated with the twenty patients were recruited over a one-week period change of gaze direction, and to attempt to recognize the (March 7 to March 13, 2011) from the Outpatient Depart- experimenter’s direction of gaze (Figure 2). Gaze direction ment at the Department of Rehabilitation, Higashi-Osaka recognition of another individual is evidently related to Yamaji Hospital, and the Midori Clinic (Osaka, Japan). activity of the superior temporal sulcus of the cerebral cortex Inclusion criteria were motility disorder in the neck of more [22]. However, when an individual is viewed from behind, than six months’ duration with chronic pain and limited with his or her face or eye invisible, the observer has to range of motion in the neck. Exclusion criteria included simulate himself with the other individual’s neck rotation cervical or systemic inflammatory signs, and history of towards the direction of gaze in order to recognize the surgery in the neck, neural blockage therapy, exercise therapy another individual’s direction of gaze. This type of motor in the neck, and medications for neck symptoms. According simulation is eponymous with motor imagery [23]. Being to these criteria, 103 of the initial 120 patient cohort were similar to real motion, motor imagery involves activity of the excluded, and the remaining 17 patients participated as motion-related cortical