This 76-year-old man developed right-hand tremor followed by hypophonia, slowed gait, and stooped posture, 7 years prior to presentation. He had also gotten lost several times when driving and needed help to find his way back home from some errands. Treatment with pramipexole within the first 6 months led to paranoia and visual hallucinations and needed to be discontinued. Similar complication occurred as he was introduced to levodopa, which was worsened by olanzapine, initiated after a visit to the emergency room. Over the next years, his balance worsened and he had falls, some associated with postural light-headedness. His sleep was complicated by dream enactment behaviors, with thrashing and shouting. After 6 years from symptom onset, he needed help with dressing, bathing, and shaving. A walker was used for ambulation to minimize the risk of falls. His hallucinations were few and far between with clozapine, but he had episodes where he would mistake his wife for an impostor.

This man’s examination demonstrated moderate to severe dementia (Montreal Cognitive Assessment [MoCA] = 9/30; MMSE = 13/28; Frontal Assessment Battery = 5/18) associated with agraphia, agra-phesthesia, astereognosis, ideomotor apraxia, and frontal release signs (positive glabellar, snout, and grasp reflexes) in the setting of advanced parkinsonism, shown in the video as stooped posture, shuffling gait, and impaired postural reflexes). The reliance on a walker only 6 years from symptom onset belies a faster speed of progression than that of Alzheimer disease.

The presence of cognitive impairment at or shortly after the onset of a parkinsonian phenotype, along with the historic presence of early hallucinations and dream enactment behaviors indicative of comorbid REM sleep behavior disorder, strongly suggested the diagnosis of dementia with Lewy bodies (DLB) (Table 33.1). The patient died 9 years after symptom onset, and DLB was confirmed at autopsy (prominent Lewy bodies in the temporal lobe and amygdala were the presumed correlates of visual hallucinations).

DLB should always be suspected in cases where dementia occurs before or within 1 year from the onset of any parkinsonian motor features. Visual but also auditory and, more rarely, olfactory and tactile hallucinations are among the earliest behavioral manifestations. Recurrent visual hallucinations are a core feature in DLB and, unlike Parkinson disease (where psychosis occurs more commonly with dopamine agonists than with levodopa), develop regardless of treatment with dopaminergic or anticholinergic treatments. Hallucinations are important clinical clues in predicting Lewy body over other pathologies. Another important feature is the marked sensitivity to neuroleptic drugs. Psychotic bouts with visual hallucinations, delusions, and paranoia can worsen when treated in an emergency setting with atypical, let alone typical, antipsychotics.

Two key cognitive features raise the stakes for DLB compared to other forms of dementia. First, fluctuating levels of overall cognition, especially in attention, within the same day, can give these patients the same erratic behavioral flavor of metabolic and infectious encephalopathies. Second, a striking visuospatial disorientation translates early on into episodes of “getting lost” when driving or having overall difficulty finding a way around hitherto familiar places. The clinical pearl is that these patients are orientation impaired early on, at a time when memory may be intact, opposite to the cognitive profile of Alzheimer disease (Table 33.2). This visuospatial disorientation is also expressed as
constructional apraxia (drawing disturbance) whereby the task of drawing intersecting pentagons is much worse early on in DLB than in other dementias.