Patient With Globus Pallidus Infarction Presenting With Reversible Dementia

A 57-year-old, right-handed woman was admitted to our hospital with complaints of behavioral disturbance. The patient had been well until 1 day before admission, when she noted memory disturbance, mild disorientation, and word-finding difficulty. On admission, her level of consciousness was normal, and her Mini-Mental State Exam (MMSE) score was 24/30. There were no motor or sensory deficits. Neuropsychological assessment revealed mild impairments in attention, verbal fluency, memory, and frontal function. On T₂-weighted and diffusion-weighted MR images, a small, high-signal-intensity lesion was observed in the left basal ganglia, mainly the left globus pallidus (Figure 1). A SPECT study showed a slight decrease in blood flow in the left basal ganglia without a decrease in the adjacent cortical blood flow. After admission, she was treated with anti-platelet agents, and her symptoms improved gradually. At her 1-month follow-up, the findings of neuropsychological evaluations were significantly improved, albeit with a residual slight memory deficit (Table 1).

Vascular dementia is one of the most common forms of dementia in adults, and most cases are caused by a series of small strokes, named multi-infarct dementia (MID). On the other hand, a small single cerebral infarction can lead to dementia, the so-called strategic infarct dementia. The locations of the culprit lesion of strategic single infarct dementia include the left angular gyrus, inferomedial temporal lobe, medial frontal lobe, thalami, left capsular genu, and caudate nuclei. Cognitive impairment caused by unilateral globus pallidus infarction is very rare, although there have been a few reported cases in which lesions of the bilateral pallidal or striatal nuclei can cause cognitive disturbances with movement disorders.^1–3 In the present case, there were impairments of general intelligence, memory, and frontal function without a decrease in cortical blood flow. These findings raise the possibility that damage of the globus pallidus affects not only the frontal lobe but also other areas important for cognitive functions, and leads to general cognitive disturbance and behavioral disorder.