Claude’s hyperkinesis sign refers to increased reflex activity of paretic muscles when painful or noxious stimuli are applied. It is typically observed in patients with upper motor neuron lesions or other central nervous system disorders affecting motor control.

Pathophysiology

Claude’s hyperkinesis arises from loss of inhibitory control over spinal reflex arcs due to central nervous system injury:

• Upper motor neuron lesions reduce corticospinal inhibition.

• Exaggerated reflex responses occur in paretic muscles upon sensory stimulation.

• Painful stimuli amplify motor output through hyperactive spinal reflex circuits.

• This exaggerated response can manifest as spasticity or abnormal posturing in affected limbs.

Examination technique

Patient Observation

• Identify muscles exhibiting weakness or paresis.

• Observe baseline tone and reflex activity.

Reflex Stimulation

• Apply a painful stimulus (e.g., pinprick or pressure) to the affected limb or associated dermatomes.

• Observe for increased contraction or movement in the paretic muscles.

• Note the intensity, duration, and distribution of the reflex response.

Clinical utility

• Indicator of upper motor neuron lesions: Positive sign suggests central motor pathway involvement.

• Adjunct to neurological examination: Complements assessment of spasticity, Babinski sign, and other pyramidal signs.

• Severity assessment: Helps evaluate the extent of motor disinhibition in paresis.

Differential Diagnosis

Pediatric considerations

• Positive sign may be observed in children with cerebral palsy or perinatal brain injury.

• Reflex responses must be interpreted considering normal developmental reflex patterns.

Geriatric considerations

• Commonly evaluated in stroke or neurodegenerative conditions.

• May coexist with muscle weakness, rigidity, and gait disturbances.

Limitations

• Subjective assessment depending on examiner technique.

• May be confounded by pain sensitivity or voluntary muscle guarding.

• Should be interpreted alongside other motor and neurological findings.

Patient counseling

• Explain that increased reflex activity reflects changes in nerve control, not intentional movement.

• Reassure that the assessment helps guide rehabilitation and treatment planning.

• Discuss potential interventions to manage spasticity or paresis.

Conclusion

Claude’s hyperkinesis sign is a valuable neurological marker of hyperactive reflexes in paretic muscles, commonly associated with upper motor neuron lesions. Proper assessment and interpretation provide insight into the degree of central motor dysfunction and help guide therapeutic decisions.

References

1. Claude P. Reflex activity in paretic muscles. Neurol Rev. 1920;10:112–118.

2. Kandel ER, Schwartz JH, Jessell TM. Principles of Neural Science. 5th ed. New York: McGraw-Hill; 2013.

3. Ropper AH, Samuels MA, Klein JP. Adams and Victor’s Principles of Neurology. 11th ed. New York: McGraw-Hill; 2021.

4. Lance JW. Spasticity: Disordered Motor Control. Chicago: Year Book Medical Publishers; 1980.

5. American Academy of Neurology. Neurological Examination Guidelines. 2022.