Trail Making Test Elucidates Neural Substrates of Specific Poststroke Executive Dysfunctions.

BACKGROUND AND PURPOSE: Poststroke cognitive impairment is typified by prominent deficits in processing speed and executive function. However, the underlying neuroanatomical substrates of executive deficits are not well understood, and further elucidation is needed. There may be utility in fractionating executive functions to delineate neural substrates. METHODS: One test amenable to fine delineation is the Trail Making Test (TMT), which emphasizes processing speed (TMT-A) and set shifting (TMT-B-A difference, proportion, quotient scores, and TMT-B set-shifting errors). The TMT was administered to 2 overt ischemic stroke cohorts from a multinational study: (1) a chronic stroke cohort (N=61) and (2) an acute-subacute stroke cohort (N=45). Volumetric quantification of ischemic stroke and white matter hyperintensities was done on magnetic resonance imaging, along with ratings of involvement of cholinergic projections, using the previously published cholinergic hyperintensities projections scale. Damage to the superior longitudinal fasciculus, which colocalizes with some cholinergic projections, was also documented. RESULTS: Multiple linear regression analyses were completed. Although larger infarcts (ß=0.37, P<0.0001) were associated with slower processing speed, cholinergic hyperintensities projections scale severity (ß=0.39, P<0.0001) was associated with all metrics of set shifting. Left superior longitudinal fasciculus damage, however, was only associated with the difference score (ß=0.17, P=0.03). These findings were replicated in both cohorts. Patients with ≥2 TMT-B set-shifting errors also had greater cholinergic hyperintensities projections scale severity. CONCLUSIONS: In this multinational stroke cohort study, damage to lateral cholinergic pathways and the superior longitudinal fasciculus emerged as significant neuroanatomical correlates for executive deficits in set shifting.

Criterion and convergent validity of the Montreal cognitive assessment with screening and standardized neuropsychological testing.

OBJECTIVES: To compare the validity of the Montreal Cognitive Assessment (MoCA) with the criterion standard of standardized neuropsychological testing and to compare the convergent validity of the MoCA with that of existing screening tools and global measures of cognition. DESIGN: Cross-sectional observational study. SETTING: Tertiary care hospital-based cognitive neurology subspecialty clinic. PARTICIPANTS: A convenience sample of 107 individuals with mild Alzheimer's disease (AD, n=75) or mild cognitive impairment (MCI, n=32) from the Sunnybrook Dementia Study. MEASUREMENTS: In addition to the MoCA, all participants completed the Mini-Mental State Examination (MMSE), the Mattis Dementia Rating Scale (DRS), and detailed neuropsychological testing. RESULTS: Convergent validity was supported, with MoCA scores correlating well with the MMSE (correlation coefficient (r)=0.66, P<.001) and the DRS (r=0.77, P<.001) and the MoCA better associated with the DRS than did the MMSE. Criterion validity was supported, with MoCA subscores according to cognitive domain correlating well with analogous neuropsychological tests and, in the case of memory (area under the receiver operating characteristic curve (AUC)=0.86), executive (AUC=0.79), and visuospatial function (AUC=0.79), being reasonably sensitive to impairment in those domains. CONCLUSION: The MoCA is a valid assessment of cognition that shows good agreement with existing screening tools and global measures (convergent validity) and was superior to the MMSE in this regard. The MoCA domain-specific subscores align with performance on more-detailed neuropsychological tests, suggesting not only good criterion validity for the MoCA, but also that it may be useful in guiding further neuropsychological testing.

A comparison of donepezil and galantamine in the treatment of cognitive symptoms of Alzheimer's disease: a meta-analysis.

This review was conducted in order to determine the efficacy of donepezil and galantamine in the treatment of cognitive symptoms of Alzheimer's disease, and also to determine whether galantamine was a superior pharmacological intervention. Meta-analytic methods were used to analyse the data from eight empirical studies which met the inclusion criteria specified. By finding the mean effect sizes of the treatment on the outcome measures of cognition, it was determined that neither drug was greatly efficacious. However, this result does not necessarily diminish the practical value of the drug. It was also found that galantamine was no better than donepezil at treating cognitive decline in AD.