Action Observation and Motor Imagery Training in Cervical Disc Herniation

The cervical spine is highly susceptible to mechanical stress and degenerative changes because of its considerable mobility. Degenerative alterations may lead to cervical disc herniation, a condition commonly associated with chronic neck pain, restricted cervical mobility, impaired function, and reduced quality of life. In addition to peripheral musculoskeletal impairments, chronic neck pain has been associated with changes in central nervous system processing, including alterations in proprioception, motor control, muscle activation, and cortical organization.

Action Observation (AO) and Motor Imagery (MI) are non-invasive, low-cost, motor learning-based rehabilitation approaches that target the central nervous system. Motor imagery involves the mental rehearsal of a movement without physical execution, whereas action observation consists of observing goal-directed movements to facilitate activation of motor-related cortical networks. Both approaches are believed to enhance neuroplasticity and improve motor performance by promoting cortical excitability and motor learning.

Previous studies have reported beneficial effects of AO and MI on pain, proprioception, motor control, and functional performance in individuals with musculoskeletal disorders. However, evidence regarding the combined application of AO and MI in individuals with cervical disc herniation remains limited, particularly in randomized controlled trials incorporating a sham intervention. The inclusion of a sham observation group using neutral nature videos is intended to distinguish the specific therapeutic effects of AO and MI from nonspecific effects related to attention and treatment participation.

The present study is designed as a randomized controlled trial to investigate the clinical effectiveness of AO and MI training as an adjunct to conventional physiotherapy in individuals with cervical disc herniation and chronic neck pain. Thirty-six participants will be randomly assigned to one of two groups. The control group will receive conventional physiotherapy combined with sham observation consisting of neutral nature videos, whereas the experimental group will receive conventional physiotherapy in addition to AO and MI training. The intervention period will last six weeks.

Clinical outcomes will be evaluated before and after the intervention. Outcome measures will include pain intensity, pressure pain threshold, neck-related disability, kinesiophobia, cervical proprioception, cervical motor control, and muscular endurance using validated assessment tools. The primary objective is to determine whether the addition of AO and MI training provides greater improvements in these clinical outcomes than conventional physiotherapy with sham observation. The findings are expected to contribute to the evidence supporting motor learning-based rehabilitation strategies and to facilitate the integration of neuroplasticity-oriented interventions into the conservative management of cervical disc herniation.

Inclusion criteria

Adults aged 18 to 65 years. Diagnosis of cervical radiculopathy confirmed by a physician based on clinical examination and magnetic resonance imaging (MRI).

History of chronic neck pain lasting at least 3 months. Sufficient active cervical range of motion to participate in the intervention (flexion and extension ≥20°, lateral flexion ≥15°, and rotation ≥30°).

Neck pain intensity of ≥3 points on the Visual Analog Scale (VAS) and neck disability of ≥10 points on the Neck Disability Index (NDI) at baseline.

Willingness to participate and provision of written informed consent.

Exclusion criteria

Inability to comply with the study protocol or cooperate with study procedures. Cognitive impairment (e.g., dementia or learning disability) that would interfere with understanding or completing the intervention or assessments.

History of cervical spine surgery. Acute trauma, fracture, tumor, infection, or other serious pathology involving the cervical spine or shoulder region.

Cervical spinal stenosis, cervical myelopathy, advanced cervical spondylosis, or other significant structural degenerative cervical spine disorders.

Uncontrolled neurological or systemic disease that could influence study participation or outcomes.

Receipt of any treatment targeting the cervical region within the previous 6 months (e.g., physiotherapy, injection therapy, or other invasive interventions).

Visual impairment, hearing impairment, or severe vestibular disorders that would prevent participation in the intervention protocol.