Associations of Prior Head Injury With Mild Behavioral Impairment Domains

Associations of Traumatic Brain Injury and Mild Behavioral Impairment With Cognitive Function and Dementia

OBJECTIVE

Traumatic Brain Injury (TBI) may contribute additional complexity to the clinical picture of mild behavioral impairment (MBI). MBI, a behavioral analog to mild cognitive impairment (MCI), is comprised of five neuropsychiatric domains: decreased motivation, affective dysregulation, impulse dyscontrol, social inappropriateness, and abnormal perception/thought content. We investigated (1) if cross-sectional associations of cognitive status with MBI symptoms differ by TBI status and (2) if prospective associations of MBI domain positivity with incident dementia risk differ by TBI status.

METHODS

2246 participants without dementia from the Atherosclerosis Risk in Communities Study were included (mean age = 75.6 years, 59.0% female). TBI was defined by self-report/ICD-9/10 codes, MBI via an established algorithm based on the Neuropsychiatric Inventory Questionnaire, and baseline cognitive status/incident dementia using neuropsychological tests, informant interviews, and hospital/death certificate codes.

RESULTS

Cross-sectionally, although MCI status was associated with greater odds of MBI, this did not differ based on TBI status (MCI with TBI: OR = 2.04, 95% CI = 1.44-2.88, MCI without TBI: OR = 1.60, 95% CI = 1.20-2.14). Individuals with MCI (with or without TBI) were more likely to have decreased motivation, affective dysregulation, and impulse dyscontrol. Prospectively, positivity in 1+ MBI domains was associated with increased risk of incident dementia, not differing by TBI status (no TBI and MBI: HR = 2.15, 95% CI = 1.55-2.99, TBI and MBI: HR = 2.62, 95% CI = 1.81-3.80).

CONCLUSIONS

Neither cross-sectional associations between cognitive status and MBI domain positivity nor prospective associations of MBI domain positivity with incident dementia risk differed by TBI status. How TBI may relate to neuropsychiatric symptomatology in the context of neurodegenerative processes requires further clarification.

Mild Behavioral Impairment in Parkinson's Disease: An Updated Review on the Clinical, Genetic, Neuroanatomical, and Pathophysiological Aspects

Neuropsychiatric symptoms (NPS), including depression, anxiety, apathy, visual hallucinations, and impulse control disorders, are very common during the course of Parkinson's disease (PD), occurring even at the prodromal and premotor stages. Mild behavioral impairment (MBI) represents a recently described neurobehavioral syndrome, characterized by the emergence of persistent and impactful NPS in later life, reflecting arisk of dementia. Accumulating evidence suggests that MBI is highly prevalent in non-demented patients with PD, also being associated with an advanced disease stage, more severe motor deficits, as well as global and multiple-domain cognitive impairment. Neuroimaging studies have revealed that MBI in patients with PD may be related todistinct patterns of brain atrophy, altered neuronal connectivity, and distribution of dopamine transporter (DAT) depletion, shedding more light on its pathophysiological background. Genetic studies in PD patients have also shown that specific single-nucleotide polymorphisms (SNPs) may be associated with MBI, paving the way for future research in this field. In this review, we summarize and critically discuss the emerging evidence on the frequency, associated clinical and genetic factors, as well as neuroanatomical and neurophysiological correlates of MBI in PD, aiming to elucidate the underlying pathophysiology and its potential role as an early "marker" of cognitive decline, particularly in this population. In addition, we aim to identify research gaps, and propose novel relative areas of interest that could aid in our better understanding of the relationship of this newly defined diagnostic entity with PD.