Mild behavioral impairment (MBI): Background, description of the construct, and criteria development

Abstract

Neuropsychiatric Symptoms (NPS) are common in dementia and pre-dementia syndromes such as Mild Cognitive Impairment (MCI). NPS in MCI confer a greater risk for conversion to dementia in comparison to MCI patients without NPS. Mild Behavioral Impairment (MBI) has been proposed as a diagnostic construct aimed to identify patients with an increased risk of developing dementia, but who may or may not have manifested cognitive symptoms. Initial discussion around the need for new MBI criteria stemmed from the annual meeting of the NPS Professional Interest Area (PIA) of the International Society to Advance Alzheimer's Research and Treatment (ISTAART) at the Alzheimer's Association International Conference (AAIC) 2012 in Vancouver, Canada. Conference proceedings and papers, Pubmed and Medline searches were performed with search criteria “mild behavioral impairment”, “MBI”, “prodromal dementia”, “neuropsychiatric symptoms of dementia”, “non-cognitive symptoms of dementia”, “NPS”, “behavioral and psychological symptoms of dementia” and “BPSD”. Both the American and United Kingdom spelling of “behavior/behaviour” were used in the search. Full text articles of relevant abstracts were reviewed, as were reference lists and citations. Authors ZI and CGL modified existing Taragano criteria, the Mendonca FTD-MCI criteria, and the NIA-AA Alzheimer's Disease criteria to incorporate current nomenclature and research. These criteria were then presented to the NPS-PIA at AAIC 2013 in Boston, Massachusetts. The criteria were then modified over the next year via in an iterative process by NPS PIA members. The final criteria then distributed to NPS PIA membership for approval and then subsequently to ISTAART for final approval prior to submission. We present the new proposed research diagnostic criteria for MBI. See Table. The MBI construct is a potential framework for detecting earlier, incipient neurodegenerative illness. The criteria extend previous research in this area and incorporate MCI into the framework. They will facilitate research into understanding NPS as a very early consequence of neurodegenerative disease in some cases, exploring targets for treatment and studying mechanisms of illness progression. The criteria will be subject to studies of reliability, concurrent validity, predictive validity and the development of biomarkers, ultimately leading to therapeutics.