Additional Cognitive Tests Research Articles

Assessment of Cognition Using Surveys and Neuropsychological Assessment: The Health and Retirement Study and the Aging, Demographics, and Memory Study

This study examines the similarity of cognitive assessments using 1 interview in a large population study, the Health and Retirement Study (HRS), and a subsample in which a detailed neuropsychiatric assessment has been performed (Aging, Demographics, and Memory Study [ADAMS]). Respondents are diagnosed in ADAMS as demented, cognitively impaired without dementia (CIND), or as having normal cognitive function. Multinomial logistic analysis is used to predict diagnosis using a variety of cognitive and noncognitive measures from the HRS and additional measures and information from ADAMS. The cognitive tests in HRS predict the ADAMS diagnosis in 74% of the sample able to complete the HRS survey on their own. Proxy respondents answer for a large proportion of HRS respondents who are diagnosed as demented in ADAMS. Classification of proxy respondents with some cognitive impairment can be predicted in 86% of the sample. Adding a small number of additional tests from ADAMS can increase each of these percentages to 84% and 93%, respectively. Cognitive assessment appropriate for diagnosis of dementia and CIND in large population surveys could be improved with more targeted information from informants and additional cognitive tests targeting other areas of brain function.

A prospective study of cognitive tests to predict performance on a standardised road test in people with dementia

Previous work by Lincoln and colleagues produced a cognitive test battery for predicting safety to drive in people with dementia. The aim was to check the accuracy of this battery and assess whether it could be improved by shortening it, including additional cognitive tests, and a measure of previous driving. Participants with dementia, who were driving, were recruited. They were assessed on cognitive tests including measures of concentration, executive function, visuospatial perception, verbal recognition memory, and speed of information processing. Patients were then assessed on the Nottingham Neurological Driving Assessment (NNDA) by an approved driving instructor (ADI), blind to cognitive test results. Seventy-five patients were recruited and completed the cognitive tests. Of these, 65 were assessed on the road. These participants were aged 59-88 (mean = 75.2, SD = 6.8) and 49 were men. Time driving varied from 19 to 73 years (mean = 52.5, SD = 10.0). Thirteen participants were unsafe and 52 safe to drive. Using a cut-off of > 0 to indicate safety to drive, the original predictive equations correctly classified 48 (76.2%) of 63 participants with complete data. Logistic regression including additional tests reduced misclassifications. A lower proportion of participants were found to be unsafe on the road than in previous studies. Nevertheless, the previously identified equation predicted safety to drive in most patients. Including additional tests reduced the misclassification rate but requires independent validation. We suggest that the cognitive test battery might be used in clinical practice to identify patients with dementia who would benefit from on-road assessment.

Validation of the stroke drivers screening assessment for people with traumatic brain injury

Cognitive impairments resulting from brain injury affect driving performance. The question of fitness to drive often arises during rehabilitation. Healthcare professionals need reliable criteria against which decisions about driving fitness can be made. Nouri et al. developed the Stroke Drivers Screening Assessment (SDSA), which was found predictive of on-road driving performance in stroke patients. The purpose of this study was to determine whether the SDSA, either alone or combined with other tests, predicted fitness to drive in brain injured people. Fifty-two participants were assessed on the SDSA plus additional cognitive tests. Their fitness to drive was examined on the public road. The SDSA predictions based on equations developed for stroke patients were not an accurate predictor of road test performance. Discriminant analysis was used to identify tests predictive of fitness to drive. Results indicated that a combination of the SDSA, the Stroop and the AMIPB Information Processing tasks correctly classified 87% of cases and may be useful predictors of driving fitness following brain injury. However, cross-validation on an independent sample of people with brain injury is required.

Auditory training improves neural timing in the human brainstem

The auditory brainstem response reflects neural encoding of the acoustic characteristic of a speech syllable with remarkable precision. Some children with learning impairments demonstrate abnormalities in this preconscious measure of neural encoding especially in background noise. This study investigated whether auditory training targeted to remediate perceptually-based learning problems would alter the neural brainstem encoding of the acoustic sound structure of speech in such children. Nine subjects, clinically diagnosed with a language-based learning problem (e.g., dyslexia), worked with auditory perceptual training software. Prior to beginning and within three months after completing the training program, brainstem responses to the syllable /da/ were recorded in quiet and background noise. Subjects underwent additional auditory neurophysiological, perceptual, and cognitive testing. Ten control subjects, who did not participate in any remediation program, underwent the same battery of tests at time intervals equivalent to the trained subjects. Transient and sustained (frequency-following response) components of the brainstem response were evaluated. The primary pathway afferent volley – neural events occurring earlier than 11 ms after stimulus onset – did not demonstrate plasticity. However, quiet-to-noise inter-response correlations of the sustained response (∼11–50 ms) increased significantly in the trained children, reflecting improved stimulus encoding precision, whereas control subjects did not exhibit this change. Thus, auditory training can alter the preconscious neural encoding of complex sounds by improving neural synchrony in the auditory brainstem. Additionally, several measures of brainstem response timing were related to changes in cortical physiology, as well as perceptual, academic, and cognitive measures from pre- to post-training.

Spatial learning, contextual fear conditioning and conditioned emotional response in Fmr1 knockout mice

Fmr1 knockout mice are an animal model for fragile X syndrome, the most common form of heritable mental retardation in humans. Fmr1 knockout mice exhibit macro-orchidism and cognitive and behavioural deficits reminiscent of the human phenotype. In the present study additional behavioural and cognitive testing was performed. Knockouts and control littermates were subjected to a spatial learning test using a plus-shaped water maze. Animals had to learn the position of a hidden escape platform during training trials. The position of this platform was changed during subsequent reversal trials. Previously reported deficits in reversal learning were replicated, but we also observed significant differences during the acquisition trials. A plus-shaped water maze experiment with daily changing platform positions failed to provide clear evidence for a working memory impairment, putatively underlying the spatial learning deficits. Two different test settings were used to examine the reported deficit of Fmr1 knockout mice in fear conditioning. Conditioned fear responses were observed in a contextual fear test, and the ability to acquire an emotional response was tested by means of response suppression in a conditioned emotional response procedure. Neither protocol revealed significant differences between controls and knockouts.

Correlation between the Folstein Mini-Mental State Examination and three methods of clock drawing scoring.

The objective of this study was to assess the correlation between (1) the Folstein Mini-Mental State Examination (MMSE) score and three methods of clock drawing scoring and (2) three methods of clock drawing scoring themselves. A convenience sample of consecutive community-dwelling seniors and attendees at a referral seniors clinic in a tertiary care hospital was used. One hundred fifty participants (72 women, 78 men) were seen with an average age of 76 years. There was a significant correlation (P = .01) between MMSE scores and all three methods of clock drawing (R = .67, .618, -.498, respectively), as well as among the three methods of clock drawing scoring. The clock drawing scores showed good correlation with the MMSE score. The clock drawing is well accepted (by the patient) and easily administered (by the health care provider). Clock drawings are recommended as the minimum requirement for cognitive assessment of elderly patients in busy primary care practices and can be used to highlight those patients requiring additional cognitive testing.

Cognitive control of differentiation in the perception of persons and objects.

Performances in tests of 4 dimensions of cognitive control that have implications for the differentiation of experience were used as bases for prediction of response to additional cognitive tests, including a Semantic Differential procedure designed to sample one aspect of differentiation in the perception of persons and objects. Factor analysis was used as a means of assessing relationships among the variables and their relationship to the sex of S. Use of husband-wife pairs as Ss provided partial control of socioeconomic status and yielded some new information concerning cognitive similarity-difference in marriage partners. The major results add to the demonstrated generality of cognitive control dimensions relevant to experiential differentiation and indicate the complexity of such differentiation with respect to persons and objects.