Are reflexes hyperactive or hypoactive in patients with severe cervical stenosis?

Reflexes in Severe Cervical Stenosis

In patients with severe cervical stenosis, reflexes are hyperactive (hyperreflexia), representing upper motor neuron dysfunction from spinal cord compression. This is a cardinal sign of cervical myelopathy and distinguishes cord compression from peripheral nerve pathology.

Pathophysiology of Hyperreflexia

• Cervical spinal cord compression disrupts descending inhibitory pathways, leading to loss of supraspinal control over spinal reflex arcs, which manifests as exaggerated deep tendon reflexes 1
• Upper motor neuron signs, including hyperreflexia, correlate directly with the presence and severity of cervical cord compression on imaging studies 1
• The frequency of upper motor neuron signs (which include hyperreflexia) was documented in 51% of patients with cervical spondylosis, and these signs correlated strongly with radiologic evidence of cord compression 1

Clinical Presentation Pattern

• Hyperreflexia typically appears alongside other myelopathic signs including gait disturbances, balance problems, fine motor skill deterioration, and positive Babinski sign 2, 3
• Motor and sensory changes are more severe in patients with absolute stenosis (spinal canal ≤10 mm anteroposterior diameter) compared to relative stenosis 4
• Patients with cervical stenosis demonstrate abnormal central motor conduction in 84% of cases with radiologic cord compression, even when clinical signs are subtle 1

Distinguishing Myelopathy from Radiculopathy

• Hyperreflexia indicates established myelopathy (cord compression), not simple radiculopathy which would present with hyporeflexia or normal reflexes in the affected nerve root distribution 2
• The presence of hyperreflexia with gait disturbance represents spinal cord compression requiring urgent surgical attention, as conservative management is futile in this setting 2
• Radiculopathy alone presents with pain, numbness, or tingling in a dermatomal pattern without hyperreflexia 3

Electrophysiological Correlation

• Abnormal motor evoked potentials correlate with upper motor neuron signs including hyperreflexia in patients with cervical stenosis 5, 1
• Central conduction delays in descending motor pathways were demonstrated in 87% of clinically unaffected patients with radiologic stenosis, indicating subclinical cord dysfunction 5
• Prolonged somatosensory and motor evoked potentials are significant independent predictors of myelopathy development in patients with cervical cord compression 6

Critical Clinical Pitfall

• Do not confuse hyperreflexia from cervical myelopathy with hyporeflexia from peripheral neuropathy or motor neuron disease, as these conditions can coexist and require electrodiagnostic studies for differentiation 4
• Hyperreflexia in the setting of cervical stenosis mandates urgent surgical evaluation, as long periods of severe stenosis lead to demyelination and potentially irreversible gray and white matter necrosis 7, 2
• Approximately 97% of patients experience symptom recovery after surgical decompression, but delayed intervention risks permanent neurological deficits that cannot be reversed 2, 3