Linking the Mini-Mental State Examination, the Alzheimer’s Disease Assessment Scale–Cognitive Subscale and the Severe Impairment Battery: evidence from individual participant data from five randomised clinical trials of donepezil

BackgroundThe Mini-Mental State Examination (MMSE), the Alzheimer’s Disease Assessment Scale–Cognitive Subscale (ADAS-Cog) and the Severe Impairment Battery (SIB) are widely used rating scales to assess cognition in Alzheimer’s disease.ObjectiveTo understand the correspondence between these rating scales, we aimed to examine the linkage of MMSE with the ADAS-Cog and SIB total and change scores.MethodsWe used individual-level data on participants with Alzheimer’s disease (n=2925) from five pivotal clinical trials of donepezil. Data were collected at baseline and scheduled visits for up to 6 months. We used equipercentile linking to identify the correspondence between simultaneous measurements of MMSE with ADAS-Cog, and SIB total and change ratings.FindingsSpearman’s correlation coefficients were of strong magnitude between the MMSE total score and the ADAS-Cog (rs from −0.82 to −0.87; p<0.05) and SIB total scores (rs from 0.70 to 0.75; p<0.05). Weaker correlations between the change scores were observed between the MMSE change score and the ADAS-Cog (week 1: r=−0.11, p=0.18; rs thereafter: −0.28 to −0.45; p<0.05) and SIB change scores (rs from 0.31 to 0.44; p<0.05). Linking suggested that the MMSE total scores were sensitive to moderate and severe cognitive impairment levels. Despite weak to moderate correlations for the change scores, moderate change levels linked well, indicating ceiling and floor effects.ConclusionsThe current results can be used in meta-analyses, data harmonisation and may contribute to increasing statistical power when pooling data from multiple sources.Clinical implicationsThe current study results help clinicians to understand these cognitive rating scale scores.

Course of Cognitive Functioning in Institutionalized Persons With Moderate to Severe Dementia: Evidence From the Severe Impairment Battery Short Version

Objectives: To adequately monitor the course of cognitive functioning in persons with moderate to severe dementia, relevant cognitive tests for the advanced dementia stages are needed. We examined the ability of a test developed for the advanced dementia stages, the Severe Impairment Battery Short version (SIB-S), to measure cognitive change over time. Second, we examined type of memory impairment measured with the SIB-S in different dementia stages. Methods: Participants were institutionalized persons with moderate to severe dementia (N = 217). The SIB-S was administered at 6-month intervals during a 2-year period. Dementia severity at baseline was classified according to Global Deterioration Scale criteria. We used mixed models to evaluate the course of SIB-S total and domain scores, and whether dementia stage at baseline affected these courses. Results: SIB-S total scores declined significantly over time, and the course of decline differed significantly between dementia stages at baseline. Persons with moderately severe dementia declined faster in mean SIB-S total scores than persons with moderate or severe dementia. Between persons with moderate and moderately severe dementia, there was only a difference in the rate of decline of semantic items, but not episodic and non-semantic items. Conclusions: Although modest floor and slight ceiling effects were noted in severe and milder cases, respectively, the SIB-S proved to be one of few available adequate measures of cognitive change in institutionalized persons with moderate to severe dementia. (JINS, 2019, 25, 204–214)

Clinical evaluation of brief cognitive assessment measures for patients with severe dementia

ABSTRACTBackground:Alzheimer's disease has become an important public health burden for older adults. Clinicians face a challenging task to efficiently evaluate cognition in dementia in clinical settings. We sought to assess the validity and inter-correlations of brief cognitive assessments in a cohort of severely demented patients.Methods:In total, 49 individual patients (N = 49) ranging in age from 62 to 97 years old were included in this performance improvement project. Over the course of two–three sessions, five cognitive instruments were administered to each patient: Severe Impairment Battery (SIB), Severe Impairment Battery-8 (SIB-8), Mini Mental State Examination (MMSE), Severe Mini Mental State Examination (sMMSE) and Brief Interview of Mental Status (BIMS). We sought to assess patient factors that might have been barriers to optimal performance on cognitive/functional tests. Researchers assessed her impression of the participants’ difficulty comprehending instructions, distractibility, apparent fatigue, and frustration, which were the four barriers rated.Results:Data were analyzed for 49 patients from the inpatient dementia unit with a total of 51 samples. All of the inter-correlations between the five cognitive instruments had Spearman coefficients of (rs) > 0.7 and were statistically significant with p < 0.001. The SIB-8 and sMMSE were positively correlated with the SIB. The perceived barrier scores ranged from 0- no issue to 1-mild issue on all five cognitive instruments.Conclusion:Brief cognitive tests designed for severe dementia such as the SIB-8 and sMMSE have been evaluated in this project to be shorter in administration duration and highly correlated with gold standard instruments: the SIB and MMSE.