A Man with Memory Loss and Odd Behavior

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Posted by Carla Rothaus

What are the main features of the behavioral variant of frontotemporal dementia? 

Many common neurologic conditions are associated with frontal network dysfunction, which causes clinically significant changes in personality and behavior. Frontal–subcortical circuitry carries projections from the thalami to the frontal lobes and connects the frontal lobes to the basal ganglia. Disruptions in nonmotor frontal–subcortical circuits are specifically linked to apathy, disinhibition, and executive dysfunction. Read the NEJM Case Records of the Massachusetts General Hospital here.

Clinical Pearls

Q: Does Lewy-body dementia include parkinsonian features?

A: The features of Lewy-body dementia include parkinsonian features, postural instability, autonomic dysfunction, repeated falls, delusions, and visual hallucinations.

Q: What are the main features of the behavioral variant of frontotemporal dementia (bvFTD)?

A: The core symptoms and natural history of bvFTD include disinhibition, apathy, loss of empathy, development of stereotyped or ritualistic behaviors, hyperorality (excessive chewing, sucking, or lip smacking), dietary changes (e.g., binge eating, weight gain, or eating inedible objects), and executive dysfunction; striking loss of insight commonly accompanies this condition. Patients with bvFTD are often referred for psychiatric evaluation and may have normal results on neuroimaging early in the disease course.


Morning Report Questions

Q: Can the symptoms of bvFTD and the frontal variant of Alzheimer’s disease (fvAD) overlap?

A: It can be difficult to distinguish fvAD with disproportional frontal features from bvFTD. The occurrence of prominent early memory loss with bvFTD can further blur the distinction. The frequency of early disease onset (at <65 years of age) among patients with bvFTD is similar to or higher than the frequency among those with fvAD. Apathy is the most common initial symptom of bvFTD and is more frequent and severe among patients with bvFTD than among those with fvAD. Criminal behaviors, such as theft, are more common among patients with bvFTD.

Q: What is Pick’s disease?

A: Pick’s disease is a subcategory of frontotemporal lobar degeneration (FTLD)-tau. FTLD is characterized by ubiquitinated protein aggregates, most commonly in neurons. Subtypes are based on the specific proteinopathy and include FTLD-tau (with tau-positive inclusions; subcategories include Pick’s disease, MAPT mutation, and others), FTLD-TDP (with inclusions positive for TAR DNA-binding protein 43), FTLD-FUS (with inclusions positive for fused in sarcoma protein), FTLD-UPS (with inclusions positive for ubiquitin proteasome system markers), and FTLD-ni (with no inclusions).

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