Prevalence of mild behavioral impairment among a Chinese cohort of elderly with mild cognitive impairment and subjective cognitive impairment

Introduction Mild behavioural impairment (MBI) describes later-life onset of sustained and meaningful neuropsychiatric symptoms (NPS) of any degree of severity before the onset of dementia or even the onset of cognitive symptoms. To our knowledge, there was only one study conducted in China and it only included non-dementia patients but did not differentiate among the cognitive groups. Methods A total of 88 subjects (28 cognitively normal, 15 subjective cognitive impairment, and 45 mild cognitive impairment) were recruited from Memory Clinic from 1st August 2020 through 16th Dec 2021. Inclusion criteria were that subjects should be of Chinese Han ethnicity. MBI was diagnosed according to the International Society to Advance Alzheimer’s Research and Treatment - Alzheimer’s Association (ISTAART-AA) criteria. MBI-checklist (MBI-C) score was either self-rated or informant-rated. NPI severity of 0 was defined as having a score of 0 for all Neuropsychiatric Inventory Questionnaire (NPI-Q) questions. NPI severity of 1 was given when the subject had a maximum score of 1-3. NPI severity of 2 referred to a subject having a score of four or over for at least one question. This cross-sectional study aimed to 1) calculate the prevalence of MBI among SCI/CN and MCI subjects in the Chinese population; 2) compare the performance of MBI-C and NPI-Q scales in MBI case ascertainment. Results Our results showed that the prevalence of MBI was 7% in CN/SCI group and 11.1% in MCI group assessed by MBI-C. The prevalence of NPS (severity >0) was 69% in CN/SCI group and 72.7% in MCI group assessed by NPI-Q. Spearman’s correlation test showed that the correlations of MBI and NPI severity were significant in overall subjects (correlation coefficient=0.3460, p=0.0011) and MCI group (correlation coefficient=0.3710, p=0.0131), and showing a trend of significance in CN/SCI group (correlation coefficient=0.3040, p=0.0503). However, Cohen’s kappa test showed that MBI-C and NPI-Q scale had only slight agreement in the overall and the both cognitive groups (overall: κ=0.0101; CN/SCI: κ=0.0667; MCI: κ=0.0917). Conclusion In conclusion, prevalence of MBI is around 7-11% among CN/SCI and MCI subjects in the Chinese population. MBI-C and NPI-Q were different tools and the former should be relied on to detect MBI. Further studies should validate an optimal cut-off score on MBI-C for each cognitive group in the Chinese population. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB of the University of Hong Kong/ Hospital Authority Hong Kong West Cluster gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript