Progressive Supranuclear Palsy
Clinical Hallmarks
- Early stiffness and falls (typically within the first year of the disease).
- upright stiff posture, back arching, and neck extension
- Prominent axial and neck rigidity (rather than limb) and retrocollic posture
- "Lurching" gait
- As opposed to PD wherein there is a stooped posture with a forward tilt and short shuffling steps.
- "Worried faces": furrowed brow (possibly due to a procerus muscle dystonia)
- This is markedly different than the lack of facial expression (hypomimia) in PD.
- Supranuclear vertical gaze palsy (see below)
- Saccadic intrusions with attempted fixation, called "square-wave jerks": the eyes jerk away and return.
Additional Clinical Features
- Pseudobulbar palsy with inappropriate laughter or crying (also see in ALS and other neurodegenerative conditions, post-stroke, in MS, and other conditions).
- Excessive drooling, dysphagia, and spastic dysarthria and dysphonia (as well as the hypophonia found in PD).
- If tremor is present, it is an action tremor (rather than the rest tremor of PD).
Gross Pathology
- Midbrain is thinned-out so much that it takes the appearance of a hummingbird’s head.
- The substantia nigra pars compacta and pars reticulata are pale.
- as opposed to PD where the pars compacta is more obviously affected.
- Pathology in the midbrain tectum results in supranuclear vertical gaze palsy (early slowing of vertical saccades), a key clinical finding in PSP.