618 Neurocognitive Disorders
supranuclear gaze palsies and axial-predominant parkinsoni sm. Pseudobulbar signs may
be present, and retropulsion is often prom inent. Neurocognitive assessment shows psy-
chomotor slowing, poor working memory, and executive dysfunction. Corticobasal degen-
eration presents with asymmetr ic rigidity, limb apraxia, postural instability, myoclonus,
alien limb phenomenon, and cortical sensory loss. Many individuals wi th behavioral-variant
major or mild frontotemporal NCD show features of motor neuron disease, which tend to
be mixed upper and predominantly lower motor neuron disease. 
Other mental disorders and medical conditions. Behavioral-variant major or mild fron-
totemporal NCD may be mistaken for a primary mental disorder, such as major depression,
bipolar disorders, or schizophrenia, and individuals with this variant often present initially
to psychiatry. Over time, the development of  progressive neurocognitive difficulties will
help to make the distinction. A careful medi cal evaluation will help to exclude treatable
causes of NCDs, such as meta bolic disturbances, nutritional deficiencies, and infections. 
Major or Mild Neurocognitive Disorder
With Lewy Bodies
Diagnostic Criteria  
A. The criteria are met for major or mild neurocognitive disorder.
B. The disorder has an insidious onset and gradual progression.
C. The disorder meets a combination of core diagnostic features and suggestive diagnos-
tic features for either probable or possibl e neurocognitive disorder with Lewy bodies.
For probable major or mild neurocognitive disorder with Lewy bodies,  the indi-
vidual has two core features, or one suggestive  feature with one or more core features.