Neural correlates of the impulse dyscontrol domain of mild behavioral impairment. (9th April 2021)

• Record Type: Journal Article
• Authors: Gill, Sascha; Wang, Meng; Mouches, Pauline; Rajashekar, Deepthi; Sajobi, Tolulope; MacMaster, Frank P; Smith, Eric E; Forkert, Nils D; Ismail, Zahinoor
• Is Part Of: International journal of geriatric psychiatry. Volume 36:Number 9(2021)
• Page Start: 1398
• Page End: 1406
• Publication Date: 2021-04-09
• Subjects: aggression -- agitation -- Alzheimer's disease -- geriatric psychiatry -- impulse dyscontrol -- mild behavioral impairment; Geriatric psychiatry -- Periodicals; Geriatric Psychiatry -- Periodicals; 618.97689
• DOI: 10.1002/gps.5540
• Languages: English
• ISSNs: 0885-6230

Abstract

Abstract: Objectives: Agitation and aggression are common in dementia and pre‐dementia. The dementia risk syndrome mild behavioral impairment (MBI) includes these symptoms in the impulse dyscontrol domain. However, the neural circuitry associated with impulse dyscontrol in neurodegenerative disease is not well understood. The objective of this work was to investigate if regional micro‐ and macro‐structural brain properties were associated with impulse dyscontrol symptoms in older adults with normal cognition, mild cognitive impairment, and Alzheimer's disease (AD). Methods: Clinical, neuropsychiatric, and T1‐weighted and diffusion‐tensor magnetic resonance imaging (DTI) data from 80 individuals with and 123 individuals without impulse dyscontrol were obtained from the AD Neuroimaging Initiative. Linear mixed effect models were used to assess if impulse dyscontrol was related to regional DTI and volumetric parameters. Results: Impulse dyscontrol was present in 17% of participants with NC, 43% with MCI, and 66% with AD. Impulse dyscontrol was associated with: (1) lower fractional anisotropy (FA), and greater mean, axial, and radial diffusivity in the fornix; (2) lesser FA and greater radial diffusivity in the superior fronto‐occipital fasciculus; (3) greater axial diffusivity in the cingulum; (4) greater axial and radial diffusivity in the uncinate fasciculus; (5) gray matter atrophy, specifically, lower cortical thickness in the parahippocampal gyrus. Conclusion: Our findings provide evidence that well‐established atrophy patterns of AD are prominent in the presence of impulse dyscontrol, even when disease status is controlled for, and possibly in advance of dementia. Our findings support the growing evidence for impulse dyscontrol symptoms as an early manifestation of AD. Key points: Impulse dyscontrol is a frequently endorsed domain of mild behavioral impairment (MBI), which is an at‐risk state for incident cognitive decline and dementia Impulse dyscontrol is common in this sample of dementia and pre‐dementia participants at a frequency of 17% in normal cognition, 43% in mild cognitive impairment, and 66% in Alzheimer's disease Impulse dyscontrol is associated with loss of white matter integrity in the cingulum, fornix, superior fronto‐occipital fasciculus, and uncinate fasciculus, as well as parahippocampal gyrus atrophy This MBI domain may serve as a potential treatment target, even in advance of dementia