Background Mild Behavioral Impairment (MBI) is a construct that describes the emergence at ≥ 50 years of age of sustained and impactful neuropsychiatric symptoms (NPS), as a precursor to cognitive decline and dementia. MBI describes NPS of any severity, which are not captured by traditional psychiatric nosology, persist for at least 6 months, and occur in advance of or in concert with Mild Cognitive Impairment (MCI). While the detection and description of MBI has been operationalized in the International Society to Advance Alzheimer’s Research and Treatment – Alzheimer’s Association (ISTAART-AA) research diagnostic criteria, there is no instrument that accurately reflects MBI as described. Objective To develop an instrument based on ISTAART-AA MBI criteria. Methods Eighteen subject matter experts participated in development using a modified Delphi process. An iterative process ensured items reflected the 5 MBI domains of 1) decreased motivation; 2) emotional dysregulation; 3) impulse dyscontrol; 4) social inappropriateness; and 5) abnormal perception or thought content. Instrument language was developed a priori to pertain to non-demented functionally independent older adults. Results We present the Mild Behavioral Impairment Checklist (MBI-C), a 34-item instrument, which can easily be completed by a patient, close informant, or clinician. Conclusion The MBI-C provides the first measure specifically developed to assess the MBI construct as explicitly described in the criteria. Its utility lies in MBI case detection, and monitoring the emergence of MBI symptoms and domains over time. Studies are required to determine the prognostic value of MBI for dementia development, and for predicting different dementia subtypes.

MBI was common in memory clinic patients without dementia and was associated with greater caregiver burden. These data show that MBI is a common and clinically relevant syndrome.

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Mild behavioral impairment (MBI) is characterized by later life acquired, sustained, and impactful neuropsychiatric symptoms (NPS) of any severity that cannot be better accounted for by other formal medical and psychiatric nosology. MBI is an "at risk" state for incident cognitive decline and dementia, and for some, MBI is the index manifestation of neurodegeneration, observed in advance of cognitive impairment. Initially described in Frontotemporal Dementia (FTD), MBI evolved to describe a preclinical stage of all cause dementia, and has been operationalized in the International Society to Advance Alzheimer's Research and Treatment-Alzheimer's Association (ISTAART-AA) proposed research diagnostic criteria. Here, we describe three cases in which patients diagnosed with a variety of dementing conditions initially presented with NPS to the Cognitive Neurosciences Clinic at the University of Calgary, Canada. All patients described in our series were given a final diagnosis of dementia; the etiology supported by clinical, cognitive, and neuroimaging findings. In all three cases, the progression to dementia was preceded by NPS that meet criteria for MBI. With these examples, we are able to illustrate that MBI can represent a premonitory stage of dementia of different etiologies. These cases demonstrate early use of the MBI checklist (MBI-C). The cases presented in this series serve as examples of NPS as early manifestations of dementia. Our case examples include both FTD and AD, and demonstrate that before a diagnosis of a neurodegenerative disease is considered, often patients will be diagnosed with and treated for a psychiatric condition. These early NPS can be characterized within the domains outlined in the ISTAART-AA MBI criteria, and detected with the MBI-C, which may help clinicians consider neurodegenerative disease in the differential diagnosis of later life onset psychiatric symptomatology.

Introduction This study aimed to develop and validate a 3‐year dementia risk score in individuals with mild cognitive impairment (MCI) based on variables collected in routine clinical care. Methods The prediction score was trained and developed using data from the National Alzheimer's Coordinating Center (NACC). Selection criteria included aged 55 years and older with MCI. Cox models were validated externally using two independent cohorts from the Prospective Registry of Persons with Memory Symptoms (PROMPT) registry and the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Results Our Mild Cognitive Impairment to Dementia Risk (CIDER) score predicted dementia risk with c‐indices of 0.69 (95% confidence interval [CI] 0.66–0.72), 0.61 (95% CI 0.59–0.63), and 0.72 (95% CI 0.69–0.75), for the internally validated and the external validation PROMPT, and ADNI cohorts, respectively. Discussion The CIDER score could be used to inform clinicians and patients about the relative probabilities of developing dementia in patients with MCI.