A validity study of the Working Group's Orientation Test for individuals with moderate to severe intellectual disability

A critical literature review of the effectiveness of various instruments in the diagnosis of dementia in adults with intellectual disabilities

Introduction

Currently, there is no consensus on dementia diagnostics in adults with intellectual disabilities (ID). There are three types of assessments available: direct cognitive tests, test batteries, and informant reports.

Methods

A systematic literature search was conducted in four databases yielding 9840 records. Relevant studies were identified and selected using predefined inclusion and exclusion criteria and then coded and classified according to assessment type. This was completed by two independent researchers, with a third consulted when discrepancies arose. The review collates diagnostic instruments and presents strengths and weaknesses.

Results

Overall 47 studies met the search criteria, and 43 instruments were extracted from the selected studies. Of which, 10 instruments were classified as test batteries, 23 were classified as direct cognitive tests, and the remaining 10 were informant reports.

Discussion

This review can recommend that cognitive test batteries can offer the most practical and efficient method for dementia diagnosis in individuals with ID.

A validity study of the Working Group's Autobiographical Memory Test for individuals with moderate to severe intellectual disability

The purpose of the present study was to investigate the validity of the Working Group's Autobiographical Memory Test as a dementia screening tool for individuals with moderate to severe intellectual disabilities (ID). Twenty-one participants with Dementia of Alzheimer's Type (DAT) and moderate to severe ID and 42 controls with similar levels of ID were tested. The majority were re-tested one year after the initial evaluation. The DAT group scored considerably lower than the control group on the initial evaluation. The controls with DS exhibited a considerable decline on the follow-up evaluation whereas other participants exhibited little changes. This demonstrates an insignificant overall difference between the DAT group and the control group on the follow-up evaluation. Virtually all participants exhibited the same scores on 3 out of 6 test items and the percentage of participants who correctly answered the remaining three test items were not significantly different from the DAT or control groups. In conclusion, the Working Group's Autobiographical Memory Test may be useful as a dementia screening tool for individuals with moderate to severe ID from DS when validated with a large sample size study. However, it is questionable whether this test is a reliable dementia screening tool for individuals with moderate to severe ID from non-DS etiologies. This test has a significant psychometric weakness because of the restricted score variability among the participants.