Relationship between smell identification testing and the neuropsychological assessment of dementia in community-dwelling adults

Olfaction and Executive Cognitive Performance: A Systematic Review

Objective tests of olfaction are widely available to aid in the assessment of olfaction. Their clearest role is in the characterization of olfactory changes, either reported by or suspected in a patient. There is a rapidly growing literature concerned with the association of olfactory changes with certain neuropsychiatric conditions and the use of olfactory testing to supplement conventional assessments in clinical and research practice is evolving. Neural pathways important for olfactory processing overlap extensively with pathways important for cognitive functioning, and especially those important for executive functioning, many of which are concentrated in the frontal lobes. Previous work has identified associations between performance on certain olfactory tests (most frequently olfactory identification) and executive functioning and behavioral measures (e.g. of impulsivity). More recently, similar associations have also been identified in non-clinical samples, raising new questions as to the utility of olfactory test scores as proxy measures for non-olfactory phenomena. In this systemic review, we sought to identify studies, both clinical and non-clinical, that investigated the associations of olfaction with performance on tasks sensitive to frontal lobe functioning. Our search criteria led to the identification of 70 studies published in English. We examined in detail and tabulated the data from these studies, highlighted each study's key findings, and critically evaluated these studies. We use the results of this review to reflect on some of the current and future challenges concerning the use of olfactory testing in clinical neuropsychiatric practice and research and speculate on the potential benefits of administering phonemic fluency in combination with olfactory testing to enhance its predictive value.

A meta-analysis of the accuracy of embedded performance validity indicators from the repeatable battery for the assessment of neuropsychological status

Objective: Meta-analyze the embedded performance validity tests of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), emphasizing two topics: diagnostic accuracy and relationships with demographics. Method: Literature was identified through a review of PsycINFO, PubMed, and Google Scholar. Bivariate linear mixed models were used for diagnostic accuracy analyses. Random-effects analysis of correlations with demographic variables was also used for the Effort Index. Results: Diagnostic accuracy analyses utilized 12 studies of the Effort Index (EI; N = 1469) and 6 studies of the Effort Scale (ES; N = 854). The EI was found to have a sensitivity of .44 (95% CI: .28 - .62), specificity of .87 (95% CI: .78 - .93), and diagnostic odds ratio (DOR) of 5.41 (95% CI: 3.74 - 7.58). The ES produced a sensitivity of .67 (95% CI: .50 - .81), specificity of .72 (95% CI: .53 - .85), and DOR of 5.97 (95% CI: 1.70 - 15.30). Meta-analysis of correlations utilized 14 samples of the EI (N = 3781), but insufficient data were available for the ES. Correlations between the EI and age (r = .10, 95% CI: .05 - .16), education (r = -.11, 95% CI: -.18 to -.04), and the RBANS Total Scale (r = -.45, 95% CI: -.62 to -.24) were significant. These results appeared to be robust to publication bias. Conclusion: Results support use of the EI over the ES; however, the latter is comparatively less studied and did not have similar variability in reported cut-off scores. ES accuracy statistics were significantly predicted by sample variables, which may be related to its relatively fewer studies. Both measures should be used cautiously in the context of genuine cognitive impairment.