Are There Underlying Neural Bases for Agitated Behaviors in Patients with Alzheimer Disease?

In a study examining agitated behaviors in Alzheimer disease (AD), researchers identified distinct neural mechanisms underlying different types of aggression, potentially advancing treatment strategies.

Agitated behaviors and aggression are frequent and distressing symptoms of AD, often leading to caregiver burden. However, the neural basis for aggression in AD remains poorly understood, highlighting the need for studies exploring its mechanisms and guiding targeted therapies.

The researchers evaluated 257 patients—180 with AD and 77 with amnestic mild cognitive impairment (aMCI). They conducted factor analysis on aggression scores from the Neuropsychiatric Inventory (NPI) and used statistical parametric mapping to assess the correlation between cerebral blood flow (CBF) and different agitated behaviors.

The results showed that refusal of care in patients with AD was associated with reduced CBF in the right hippocampus. No specific brain regions related to refusal of care were identified in patients with aMCI. Violent behavior was correlated with decreased CBF in the right temporal pole and medial frontal lobe in both patients with AD and patients with aMCI.

Limitations of the study include the inability to identify related brain regions in patients with aMCI, which may require further research.

“These findings suggest that aggression, measured using NPI includes two distinct symptoms, refusal of care and violent behavior, having different underlying neural bases,” the study authors concluded.

Reference

Kashibayashi T, Kanemoto H, Takahashi R, et al. Neural basis of agitated behaviors in patients with amnestic mild cognitive impairment and Alzheimer’s disease. J Alzheimer’s Dis. 2024;100(4):1399-1406. doi: 10.3233/JAD-240256.