Which of the following physical examination findings is an upper motor neuron sign highly indicative of cervical spondylotic myelopathy?

Explanation:
A positive Hoffmann's sign (flexion of the thumb and index finger when the middle finger nail is flicked) is a classic upper motor neuron sign indicating spinal cord compression in the cervical spine. Deep tendon reflexes below the level of compression would typically be hyperactive, not absent. Reference: Hoppenfeld S. Physical Examination of the Spine and Extremities.