Which syndrome is classically associated with vertical gaze palsy, backward falls, and an applause sign?

• A. Corticobasal Degeneration
• B. MSA
• C. Semantic Dementia
• D. Progressive Supranuclear Palsy

Answer: (D)

Progressive supranuclear palsy is characterized by a classic triad that reflects where the disease affects the brain. The vertical gaze palsy arises from degeneration of the midbrain vertical gaze centers, so voluntary up-and-down eye movements become slow or lost while reflexive movements may be relatively preserved early on. This specific eye-movement impairment is a hallmark feature that helps distinguish PSP from other parkinsonian syndromes.

Backward falls come from early axial postural instability and rigidity, a consequence of the widespread brainstem and basal ganglia involvement in PSP. This instability often appears earlier in the disease course than tremor or other parkinsonian features.

The applause sign points to frontal-subcortical dysfunction. In PSP, impaired inhibitory control and frontal-executive dysfunction can cause a patient to continue clapping after the cue to stop, illustrating the breakdown of selective motor control and inhibition that accompanies this syndrome.

Other conditions on the list may have parkinsonism or cognitive changes, but they do not typically present with the combination of vertical gaze palsy, early backward falls, and the applause sign as a single, defining pattern.