Mild Behavioral Impairment: A New Prodromal Syndrome for Dementia

In this review, it is aimed to discuss neuropsychiatric symptoms as prodromal symptoms of dementia syndromes, to define the concept of 'Mild Behavioral Impairment', and to introduce the 'Mild Behavioral Impairment Checklist'. Neuropsychiatric symptoms (NPS) represent non-cognitive symptoms and behaviors in dementia patients. The frequency of NPS accompanying dementia increases as the disease progresses. Studies reveal that NPS are seen in patients with dementia as well as in the elderly without cognitive complaints, individuals with subjective cognitive complaints, and individuals diagnosed with mild cognitive impairment. Based on these findings, identifying and detecting these symptoms were thought to be useful in predicting the development of dementia in cases where cognitive symptoms have not yet appeared. 'Mild Behavioral Impairment' was first defined by Taragano and Allegri, and it was introduced as a concept that includes neurobehavioral symptoms seen in elderly people for at least 6 months and that do not meet the diagnostic criteria of any other psychiatric syndrome. Mild Behavioral Impairment Checklist (MBI-C) has been developed recently which consists of 34 questions including apathy, mood, impulse dyscontrol, social inappropriateness, abnormal thinking, and perception. Studies on the neurobiological basis of these sub-domains and their relationship with biomarkers gained momentum with the definition of the concept and the development of MBI-C. However, the concept is still very new and it is possible for people to be over-diagnosed and to face the risk of stigmatization during the evaluation. Therefore, studies with large samples are needed. Demonstrating the validity of this concept will also serve the purpose of identifying the subjects with a neurodegenerative disease without any cognitive complaints yet at a very early stage in clinical studies. Keywords: Mild behavioral impairment, neuropsychiatric symptoms, prodromal dementia.