Head-Eye Movement Control Tests in Chronic Neck Pain
Neck pain is a common problem, with lifetime prevalence in the general population worldwide of up to 71%. Impaired head-eye movement control is an identified problem in patients with chronic neck pain, particularly in patients with whiplash associated disorders (WAD). Symptoms associated with head-eye movement control impairment are dizziness, headache, light-headedness and visual disorders. Movements requiring the coordination of neck, head and eyes are known to provoke those symptoms. A well-known example is driving a car after whiplash trauma, where Gimse found changed eye movements during car driving. He also found altered eye movements during reading and differences in smooth pursuit eye movements with the head in the neutral position. In patient anamnesis, symptom provocation was found during walking, fast head rotations and observation of moving objects. Oculomotor dysfunctions after cervical trauma were described by Hildingssons and colleagues. Yahia and colleagues found abnormal dynamic and static balance in patients with chronic neck pain and dizziness. Humphreys and colleagues investigated neck pain in 180 patients: one third reported dizziness.
Following Treleaven and colleagues, dizziness is a frequent symptom in patients with neck pain and WAD. They assumed the underlying mechanism to be a convergence dysfunction of the sensorimotor input from the cervical spine, the vestibulum and the visual postural system. This theory is also supported by other authors. Heikkilä et al., found a reduced range of cervical motion and decreased upper cervical proprioception, which affects the voluntary eye movement. Peterson postulated the head-neck motor system as an ideal model for understanding issues of complex motor control and Armstrong, mentioned that sensory information from neck proprioceptors is processed in tandem with information from the vestibulum, cerebellum and cortex.
Following diagnosis of a dysfunction of convergence, the management of an intervention is based on the clinical presentation and the functional impairment. The following assessments are recommended to measure the functional impairment and are used in clinical practice: joint position error (JPE), "The Fly" movement method, smooth pursuit neck torsion test (SPNT), postural stability and balance, as well as oculomotory and head-eye coordination tests.
In this study, the selection of our tests was influenced by some of the research tests outlined above. The test battery had to meet the following criteria: have the ability to transfer the research results into practice; be simple; performed without high-tech equipment; easy to learn; and, preferably, be low cost. The test battery of five tests was performed in the sitting position and the standing position. The latter, with feet together to achieve a more challenging balance position.
Eye movement was tested according to Jull and colleagues. They tested eye-follow in both neutral and in relative 45°neck rotation, using the elements of the smooth pursuit neck torsion test from Tjell. Tjell compared eye movements performed with the head in neutral position to a position in 45° relative head rotation. He reported significant differences between these two positions in patients with whiplash trauma compared to patients with vestibular pathology. Because of the unavailablity of equipment for standardizing eye movement velocity, in the present study the eye movement tests were performed differently to Tjell et al.. The participants were asked to move their eyes horizontally from side to side as quickly as possible, while actively maintaining their initial fixed head position.
Treleaven and colleagues showed that patients with WAD have decreased velocity of movement in the sequential head and eye movement test and in the gaze stability task, compared to healthy controls. Furthermore, patients with WAD have a reduced active range of motion of the cervical spine in the gaze stability test. These altered movement patterns were associated with a higher score in the Neck Disability Index (NDI). However, this data was collected using sophisticated laboratory equipment to measure eye movement in association with head movement. A physiotherapeutic diagnosis, is based on visual observation of the patients' impaired head-eye movement. According to Treleaven visual clinical observation of the quality of head and eye movement, in conjunction with symptom provocation, is the suggested method for assessment of oculomotory dysfunction. Qualitative and quantitative aspects of movement, as well as symptom provocation, are references for physiotherapeutic intervention. Range of motion and velocity of movement is difficult to measure without technical equipment but the quality of movement control can be visually inferred. To date, the reliability of visual observation of head-eye coordination tests has not been investigated.
The main objectives of the present study were to:
Our hypothesis was that, "Visual assessments by physiotherapists of head-eye movement control deficit are reliable and that these tests are able to discriminate between controls and patients".
We also hypothesized a greater head-eye control deficit in the standing position compared to sitting, since the latter is a more challenging balance position and requires increased coordination.
Background
Neck pain is a common problem, with lifetime prevalence in the general population worldwide of up to 71%. Impaired head-eye movement control is an identified problem in patients with chronic neck pain, particularly in patients with whiplash associated disorders (WAD). Symptoms associated with head-eye movement control impairment are dizziness, headache, light-headedness and visual disorders. Movements requiring the coordination of neck, head and eyes are known to provoke those symptoms. A well-known example is driving a car after whiplash trauma, where Gimse found changed eye movements during car driving. He also found altered eye movements during reading and differences in smooth pursuit eye movements with the head in the neutral position. In patient anamnesis, symptom provocation was found during walking, fast head rotations and observation of moving objects. Oculomotor dysfunctions after cervical trauma were described by Hildingssons and colleagues. Yahia and colleagues found abnormal dynamic and static balance in patients with chronic neck pain and dizziness. Humphreys and colleagues investigated neck pain in 180 patients: one third reported dizziness.
Following Treleaven and colleagues, dizziness is a frequent symptom in patients with neck pain and WAD. They assumed the underlying mechanism to be a convergence dysfunction of the sensorimotor input from the cervical spine, the vestibulum and the visual postural system. This theory is also supported by other authors. Heikkilä et al., found a reduced range of cervical motion and decreased upper cervical proprioception, which affects the voluntary eye movement. Peterson postulated the head-neck motor system as an ideal model for understanding issues of complex motor control and Armstrong, mentioned that sensory information from neck proprioceptors is processed in tandem with information from the vestibulum, cerebellum and cortex.
Following diagnosis of a dysfunction of convergence, the management of an intervention is based on the clinical presentation and the functional impairment. The following assessments are recommended to measure the functional impairment and are used in clinical practice: joint position error (JPE), "The Fly" movement method, smooth pursuit neck torsion test (SPNT), postural stability and balance, as well as oculomotory and head-eye coordination tests.
In this study, the selection of our tests was influenced by some of the research tests outlined above. The test battery had to meet the following criteria: have the ability to transfer the research results into practice; be simple; performed without high-tech equipment; easy to learn; and, preferably, be low cost. The test battery of five tests was performed in the sitting position and the standing position. The latter, with feet together to achieve a more challenging balance position.
Eye movement was tested according to Jull and colleagues. They tested eye-follow in both neutral and in relative 45°neck rotation, using the elements of the smooth pursuit neck torsion test from Tjell. Tjell compared eye movements performed with the head in neutral position to a position in 45° relative head rotation. He reported significant differences between these two positions in patients with whiplash trauma compared to patients with vestibular pathology. Because of the unavailablity of equipment for standardizing eye movement velocity, in the present study the eye movement tests were performed differently to Tjell et al.. The participants were asked to move their eyes horizontally from side to side as quickly as possible, while actively maintaining their initial fixed head position.
Treleaven and colleagues showed that patients with WAD have decreased velocity of movement in the sequential head and eye movement test and in the gaze stability task, compared to healthy controls. Furthermore, patients with WAD have a reduced active range of motion of the cervical spine in the gaze stability test. These altered movement patterns were associated with a higher score in the Neck Disability Index (NDI). However, this data was collected using sophisticated laboratory equipment to measure eye movement in association with head movement. A physiotherapeutic diagnosis, is based on visual observation of the patients' impaired head-eye movement. According to Treleaven visual clinical observation of the quality of head and eye movement, in conjunction with symptom provocation, is the suggested method for assessment of oculomotory dysfunction. Qualitative and quantitative aspects of movement, as well as symptom provocation, are references for physiotherapeutic intervention. Range of motion and velocity of movement is difficult to measure without technical equipment but the quality of movement control can be visually inferred. To date, the reliability of visual observation of head-eye coordination tests has not been investigated.
The main objectives of the present study were to:
Develop a test battery
Investigate the inter-tester reliability of the visual observation of ten videotaped head-eye coordination tests
Determine the discriminative validity of these tests in patients with chronic neck pain compared to healthy controls
Our hypothesis was that, "Visual assessments by physiotherapists of head-eye movement control deficit are reliable and that these tests are able to discriminate between controls and patients".
We also hypothesized a greater head-eye control deficit in the standing position compared to sitting, since the latter is a more challenging balance position and requires increased coordination.
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