American Board of Psychiatry and Neurology (ABPN) Practice Exam

What is the most likely diagnosis for a patient with cognitive impairment, visual hallucinations, and Parkinson's symptoms?

1. Frontotemporal dementia

2. Dementia with Lewy bodies

3. Alzheimer's dementia

4. Normal-pressure hydrocephalus

The correct answer is: Dementia with Lewy bodies

The most likely diagnosis in this scenario is dementia with Lewy bodies. This condition is characterized by the presence of both cognitive impairment and motor symptoms similar to those seen in Parkinson's disease, such as rigidity, bradykinesia, and tremor. Importantly, visual hallucinations are a prominent feature of dementia with Lewy bodies and often occur early in the disease process, which distinguishes it from other types of dementia. Patients with dementia with Lewy bodies may experience fluctuating cognition, where their attention and alertness vary significantly, and this can occur alongside the hallmark symptoms of Parkinsonism. Additionally, the presence of Lewy bodies, which are abnormal aggregates of protein within neurons, supports the diagnosis. Other types of dementia have different clinical presentations. For example, frontotemporal dementia primarily affects personality, behavior, and language skills, typically without the motor symptoms described. Alzheimer's dementia usually presents with profound memory impairment early on and does not typically feature visual hallucinations prominently, especially not in the same context as seen in dementia with Lewy bodies. Normal-pressure hydrocephalus is associated with a classic triad of symptoms: gait disturbance, urinary incontinence, and cognitive impairment, and does not typically involve visual hallucinations or Parkinsonian features. Thus