This patient most likely has cognitive impairment due to cerebrovascular disease, otherwise known as vascular neurocognitive disorder (VND). VND comprises a group of pathophysiologically distinct processes and thus has heterogeneous clinical presentations. Because it encompasses a continuum of cognitive disorders, from mild cognitive impairment to dementia, that result from cerebrovascular disease, validated diagnostic criteria do not exist. Widely accepted clinical criteria require evidence of a cognitive disorder plus a previous clinical stroke or neuroimaging evidence that confirms the existence of cerebrovascular disease. A relationship between the cognitive decline and cerebrovascular disease should exist, as it does with this patient. The description of the “ministrokes” experienced by this patient is consistent with a history of previous lacunar strokes. Supportive features include gait disturbance, pseudobulbar affect (a neurologic disorder characterized by involuntary outbursts of laughing and/or crying that are out of proportion to the emotions being experienced), incontinence, depression, and focal neurologic signs. Cognitive impairment generally is characterized by executive dysfunction, slowed mental processing, and impaired attention, as is exhibited by this patient.

Coexisting Alzheimer disease is found at autopsy in a large number of patients with VND. However, the lack of prominent memory impairment, presence of focal neurologic symptoms and signs, and stepwise decline seen in this patient are more consistent with a clinical diagnosis of VND than Alzheimer disease.

Although this patient has some overlapping features typically associated with normal pressure hydrocephalus, such as urinary incontinence, magnetic gait, and cognitive decline, he lacks the neuroimaging findings of enlarged ventricles or hydrocephalus typically seen in this disorder.

This patient has some findings consistent with Parkinson disease, such as shuffling gait and executive dysfunction, but lacks other typical examination findings, such as asymmetric parkinsonism, resting tremor, stooped posture, and decline in fine motor movements. Underlying Parkinson disease is thus unlikely to be the cause of his symptoms.