Bregje A. Appels

Gait stability and variability measures show effects of impaired cognition and dual tasking in frail people

BackgroundFalls in frail elderly are a common problem with a rising incidence. Gait and postural instability are major risk factors for falling, particularly in geriatric patients. As walking requires attention, cognitive impairments are likely to contribute to an increased fall risk. An objective quantification of gait and balance ability is required to identify persons with a high tendency to fall. Recent studies have shown that stride variability is increased in elderly and under dual task condition and might be more sensitive to detect fall risk than walking speed. In the present study we complemented stride related measures with measures that quantify trunk movement patterns as indicators of dynamic balance ability during walking. The aim of the study was to quantify the effect of impaired cognition and dual tasking on gait variability and stability in geriatric patients.MethodsThirteen elderly with dementia (mean age: 82.6 ± 4.3 years) and thirteen without dementia (79.4 ± 5.55) recruited from a geriatric day clinic, walked at self-selected speed with and without performing a verbal dual task. The Mini Mental State Examination and the Seven Minute Screen were administered. Trunk accelerations were measured with an accelerometer. In addition to walking speed, mean, and variability of stride times, gait stability was quantified using stochastic dynamical measures, namely regularity (sample entropy, long range correlations) and local stability exponents of trunk accelerations.ResultsDual tasking significantly (p < 0.05) decreased walking speed, while stride time variability increased, and stability and regularity of lateral trunk accelerations decreased. Cognitively impaired elderly showed significantly (p < 0.05) more changes in gait variability than cognitive intact elderly. Differences in dynamic parameters between groups were more discerned under dual task conditions.ConclusionsThe observed trunk adaptations were a consistent instability factor. These results support the concept that changes in cognitive functions contribute to changes in the variability and stability of the gait pattern. Walking under dual task conditions and quantifying gait using dynamical parameters can improve detecting walking disorders and might help to identify those elderly who are able to adapt walking ability and those who are not and thus are at greater risk for falling.

Treatment effects of rivastigmine on cognition, performance of daily living activities and behaviour in Alzheimer's disease in an outpatient geriatric setting

We investigated rivastigmine effectiveness in 84 Alzheimer outpatients, with a special focus on behavioural problems. Cognition, activities in daily living (ADL) and behaviour were assessed during 30 months. Changes in test results between 6 months and baseline were compared with a historical control cohort of Alzheimer patients (n = 69) by performing t‐tests and calculation of Cohens d and standardised response mean (SRM).

Effectiveness of family meetings for family caregivers on delaying time to nursing home placement of dementia patients: A randomized trial

Background Interventions relieving the burden of caregiving may postpone or prevent patient institutionalization. The objective of this study was to determine whether a family meetings intervention was superior to usual care in postponing nursing home placement of patients with dementia. Methods A randomized multicenter trial was conducted among 192 patients with a clinical diagnosis of dementia living at home at enrolment and their primary family caregiver. Dyads of caregivers and patients were randomized to the family meetings intervention (n = 96) or usual care (n = 96) condition. The intervention consisted of two individual sessions with the primary caregiver and four family counseling sessions that included family members and friends. The primary outcome measure was the time until institutionalization of the patient. Intention-to-treat as well as per protocol analyses were performed. Survival analyses were carried out to evaluate the effectiveness of the intervention. Results During 18 months follow-up 23 of 96 relatives with dementia of caregivers in the intervention group and 18 of 96 relatives with dementia of caregivers in the usual care group were institutionalized. No significant difference between the intervention and the usual care group was found in time until institutionalization (adjusted hazard ratio (HR) 1.46, 95% confidence interval (CI) 0.78 to 2.74). The per-protocol analysis revealed no significant effect either (adjusted HR 0.57, 95% CI 0.21 to 1.57), although the number of placements among the adherers was relatively low (9.4%). A subgroup effect was found for patients’ age, with a significantly higher risk of institutionalization for ‘younger’ patients in the intervention group compared with the usual care group (adjusted HR = 4.94, 95% CI 1.10 to 22.13). Conclusion This family meetings intervention for primary caregivers of patients with dementia did not postpone patient institutionalization more than usual care. Trial Registration: Controlled-Trials.com ISRCTN90163486

Does Adaptive Cognitive Testing Combine Efficiency with Precision? Prospective Findings

Longer cognitive tests, such as the Alzheimers disease assessment scale (ADAS-cog) or the Cambridge cognitive examination (CAMCOG), are more precise but less efficient than briefer tests, such as the Mini Mental State Examination (MMSE). We examined if computerized adaptive testing (CAT) of cognitive impairment can combine brevity with precision by tailoring a precise test to each individual patient. We conducted a prospective study of 84 participants [normal aging, n = 41; mild cognitive impairment (MCI), n = 21; dementia, n = 22]. CAT estimated a participants ability during testing by selecting only items of appropriate difficulty from either the CAMCOG or the CAMCOG supplemented with ADAS-cog items and neuropsychological tests (the CAMCOG-Plus). After tailored testing with CAT, the remaining CAMCOG and CAMCOG-Plus items not selected by CAT were administered. The time needed to complete the CAT was compared to that needed for the whole CAMCOG and CAMCOG-Plus. Results showed that testing time reductions achieved with CAT were 37% or more compared to the whole CAMCOG and 55% or more compared to the whole CAMCOG-Plus. Estimated ability levels with CAT were in excellent agreement with those based on the whole CAMCOG and CAMCOG-Plus (intraclass correlations 0.99 and 0.98, respectively). Diagnostic accuracy of detecting mild dementia and MCI seemed better for the CAT administered tests than for the MMSE, but the differences were not significant. We conclude that adaptive testing combines brevity with precision, especially in grading the severity of cognitive impairment.

FC02-05 - Towards combining precision and brevity: a prospective study of adaptive cognitive testing

Objectives To examine whether cognitive testing can be tailored to individual patients by selecting only items of appropriate difficulty from a large and precise neuropsychological battery. The advantage is a combination of measurement precision with the brevity (of shorter tests). Methods 39 patients with cognitive complaints and 8 partners who visited a geriatric day care clinic were randomly assigned to administration of the CAMCOG or an extended CAMCOG i.e. with ADAS-cog and neuropsychological tests. Item difficulties were estimated and their validity examined with Rasch analysis. Tailored testing was achieved by Computerised Adaptive Testing (CAT). CAT repeatedly selected an easier item after an incorrect response and a more difficult item after a correct response to estimate the total score. CAT finished the item selection after reaching sufficient reliability (standard error Results For test reductions by CAT ranging from 25 to 15 items, intraclass correlations between the CAT estimated total score and actual total score (CAT administered plus remaining items) ranged from .99 to .98 for the CAMCOG and from 0.98 to 0.91 for the extended CAMCOG. Testing time reduction ranged from 42-55% for the CAMCOG (M testing time CAMCOG 39.6 minutes, M testing times CAT 22.9 to 17.8 minutes) and from 45-68% for the extended CAMCOG (M testing time extended CAMCOG 111.3 minutes, M testing times CAT 61-35 minutes). Conclusions Substantial test reductions and excellent agreement with the whole battery supports the use of tailored cognitive testing to economically administer batteries that are time consuming in their entire form.

Validering van de Seven Minute Screen voor gebruik in de geheugenpolikliniek

Cognitive tests play a crucial part in the assessment of dementia. In 1998 the Seven Minute Screen was developed by Solomon and colleagues. The test was originally designed to distinguish between Alzheimers disease (AD) and normal ageing, and research showed that the instrument is highly sensitive to AD. Subsequent research also proved the diagnostic accuracy of the Seven Minute Screen in the detection of other common types of dementia, such as vascular dementia, frontotemporal dementia and dementia with Lewy bodies. This article reports new research on the predictive validity of the Seven Minute Screen using 289 cognitively intact subjects, 175 patients with MCI and 563 patients with dementia in the setting of a memory clinic. In addition, a comparison is made with the Mini Mental State Examination (MMSE). The study demonstrates that the Seven Minute Screen is a valuable screening instrument for all common types of dementia, and it has added value to the MMSE. The sensitivity for dementia is 96 % and the specificity 93 %, in comparison to 69 and 98 % for the MMSE (< 24). The sensitivity for the various types of dementia is consistently high, ranging from 92 % for a subcortical dementia to 97 % for AD. The Seven Minute Screen requires little training, and combines a short administration time with a high diagnostic accuracy. This makes the Seven Minute Screen useful for application in memory clinics.

Validering van de Seven Minute Screen voor gebruik in de geheugenpolikliniek@@@Validation of the Seven Minute Screen for use in a memory clinic

Cognitive tests play a crucial part in the assessment of dementia. In 1998 the Seven Minute Screen was developed by Solomon and colleagues. The test was originally designed to distinguish between Alzheimers disease (AD) and normal ageing, and research showed that the instrument is highly sensitive to AD. Subsequent research also proved the diagnostic accuracy of the Seven Minute Screen in the detection of other common types of dementia, such as vascular dementia, frontotemporal dementia and dementia with Lewy bodies. This article reports new research on the predictive validity of the Seven Minute Screen using 289 cognitively intact subjects, 175 patients with MCI and 563 patients with dementia in the setting of a memory clinic. In addition, a comparison is made with the Mini Mental State Examination (MMSE). The study demonstrates that the Seven Minute Screen is a valuable screening instrument for all common types of dementia, and it has added value to the MMSE. The sensitivity for dementia is 96 % and the specificity 93 %, in comparison to 69 and 98 % for the MMSE (< 24). The sensitivity for the various types of dementia is consistently high, ranging from 92 % for a subcortical dementia to 97 % for AD. The Seven Minute Screen requires little training, and combines a short administration time with a high diagnostic accuracy. This makes the Seven Minute Screen useful for application in memory clinics.

Individualized evaluation of cholinesterase inhibitors effects in dementia with adaptive cognitive testing

Computerized Adaptive Testing (CAT) of cognitive function, selects for every individual patient, only items of appropriate difficulty to estimate his or her level of cognitive impairment. Therefore, CAT has the potential to combine brevity with precision. We retrospectively examined the evaluation of treatment effects of cholinesterase inhibitors by CAT using longitudinal data from 643 patients from a Dutch teaching hospital who were diagnosed with Alzheimer disease or Lewy Body disease. The Cambridge Cognitive Examination (CAMCOG) was administered before treatment initiation and after intervals of six months of treatment. A previously validated CAT was simulated using 47 CAMCOG items. Results demonstrated that the CAT required a median number of 17 items (inter‐quartile range 16–20), or a corresponding 64% test reduction, to estimate patients’ global cognitive impairment levels. At the same time, intraclass correlations between global cognitive impairment levels as estimated by CAT or based on all 47 CAMCOG items, ranged from 0.93 at baseline to 0.91–0.94 at follow‐up measurements. Slightly more people had substantial decline on the original CAMCOG (N = 31/285, 11%) than on the CAT (N = 17/285, 6%). We conclude that CAT saves time, does not lose much precision, and therefore deserves a role in the evaluation of treatment effects in dementia. Copyright

The effect of different cognitive domains on dual-task cost of gait in cognitive impaired elderly

Conference Theme: Towards Successful Aging: Harmony of Mental, Physical, and Social Life In collaboration with the Korean Association for Geriatric PsychiatryObjective: For persons with dementia performance of a cognitive task during a motor task is associated with impaired gait stability and increased fall risk. While gait with and without dual tasking has often been the object studies, few studies have investigated the relationship between different cognitive domains and gait stability. Methods: Seventeen elderly with impaired cognition, who underwent neuropsychological examination, participated (77.2±6.7 years). Four cognitive domains were assessed: 1) attention and psychomotor speed; 2) executive functioning; 3) memory; 4) visuospatial and constructive abilities (fourteen cognitive variables). To assess gait, participants walked for three minutes at self-selected pace, once under single (ST) and once under dual task (DT) condition (letterfluency). While walking, trunk accelerations were registered from which parameters were calculated that quantify gait stability. To examine differences in gait parameters between ST and DT conditions, t-tests were applied. Dual-task cost (DTC) was calculated for all gait parameters as:(DT-ST) /ST). Partial least squares regression analysis was applied to examine the effects of neuropsychological tests, representing the cognitive domains, on DTC. Significant components and contributions of cognitive variables were examined by means of their loads. Results: A significant effect of dual tasking was observed for all gait variables: walking speed, stride time variability and the accelerometer data that quantify trunk variability. PLS analyses revealed a combination of 4 components to account for the variance, of DTC with R-values ranging between 0.67-0.87. Analysis of the weight revealed not only an association with gait deficits and executive function, but also with memory and visual spatial and constructive abilities. Conclusion: More insight in the relation between different cognitive functions with motor function might be of importance for the early diagnosis of dementia or mild cognitive impairments, since a decline in gait control and dual tasking even occurs in preclinical stages before cognitive decline occurs.

Adaptive testing combines precision with brevity in the grading of cognitive impairment.

Hans Wouters, Bregje Appels, Jos Van Campen, Robert Lindeboom, Maarten Buiter, Aeilko H. Zwinderman, Willem A. van Gool and Ben Schmand Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Amsterdam, The Netherlands Department of Neurology, Academic Medical Center, Amsterdam, The Netherlands Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands Department of Medical Psychology, Slotervaart Hospital, Amsterdam, The Netherlands Department of Geriatric Medicine, Slotervaart Hospital, Amsterdam, The Netherlands