Core features - all of the following:
(1) insidious onset
(2) progressive course
(3) no other identifiable cause (no other explanation for the findings)
(4) cortical dysfunction (see below)
(5) extrapyramidal dysfunction (see below)
Cortical dysfunction - at least one of the following:
(1) cortical sensory loss
(2) sensory or visual hemineglect
(3) asymmetric or focal myoclonus
(4) alien limb phenomenon
(5) apraxia of speech or nonfluent aphasia
(6) asymmetrical or focal ideomotor apraxia
(7) constructional apraxia
Extrapyramidal dysfunction - at least one of the following:
(1) asymmetrical or focal appendicular dystonia
(2) asymmetrical or focal appendicular rigidity AND absence of a sustained response to L-dopa
Supportive evidence:
(1) relative preservation of learning and memory
(2) variable degree of focal or lateralized cognitive dysfunction
(3) CT or MRI evidence of focal or asymmetrical cortical atrophy that is usually maximal in the parietofrontal lobes
(4) focal or asymmetric hypoperfusion on SPECT or PET scan, typically maximal in the parietofrontal lobes, with or without involvement of the basal ganglia and/or thalamus
