Search

Introduction: Motor slowness (bradykinesia) is a core feature of Parkinson's disease (PD). It is often assumed that patients show mental slowness (bradyphrenia) as well; however, evidence for this is debated. The aims of this study were to determine whether PD patients show mental slowness apart from motor slowness and, if this is the case, to what extent this affects their performance on neuropsychological tests of attention, memory, and executive functions (EF)., Method: Fifty-five nondemented PD patients and 65 healthy controls were assessed with a simple information-processing task in which reaction and motor times could be separated. In addition, all patients and a second control group (N = 138) were assessed with neuropsychological tests of attention, memory, and EF., Results: While PD patients showed significantly longer reaction times than healthy controls, their motor times were not significantly longer. Reaction and motor times were only moderately correlated and were not related to clinical measures of disease severity. PD patients performed significantly worse on tests of attention and EF, and for the majority of neuropsychological tests 11-51% of the patients showed a clinically impaired performance. Reaction times did not, however, predict patients' test performance, while motor times were found to have a significant negative influence on tests of attention., Conclusions: PD patients show mental slowness, which can be separated from motor slowness. Neuropsychological test performance is not influenced by mental slowness; however, motor slowness can have a negative impact. When interpreting neuropsychological test performance of PD patients in clinical practice, motor slowness needs to be taken into account.

The present paper addresses the psychometric quality of the shortened Dutch version of The Awareness of Social Inference Test (TASIT), a social cognition task comprising dynamic social interactions. Because the original TASIT required a rather long administration time, two shortened parallel forms were developed. Results showed that TASIT-short was feasible and that the two alternate forms were reasonably comparable in a group of neurologically healthy individuals (N = 98). Also, the results confirmed the ecological validity of TASIT-short in this healthy group. The test appeared sensitive to brain injury as it differentiated between the healthy subjects and a group of patients with acquired brain injury (N = 16). On the basis of the present study we conclude that TASIT-short has added value to the assessment of social cognition in patients with acquired brain injury.

A major goal of neuropsychological assessment is predicting a person's level of functioning in daily life. Making predictions about everyday executive functioning based on tests is problematic because of the contrast between demands made in the test environment and demands made in everyday life (Shallice & Burgess, 1991). As executive functions play an important role in independent functioning, tests with robust psychometric properties and ecologically validity are needed. We developed the Executive Secretarial Task (EST) and assessed 92 participants: 35 brain-injured patients and 57 controls. Analyses showed the EST is sensitive to executive problems and has concurrent and ecological validity.

To study the presence and nature of dysexecutive problems after CHI, a series of unstructured tasks tapping executive functioning were selected. These were administered to a group of 51 participants with CHI in the chronic stage (i.e. several years post-injury) and to 45 healthy controls. In addition, well-known structured tests of attention and planning were administered. Of the executive tasks, only the Executive Route Finding task showed a significant difference between both groups. A multivariate analysis on the attention tests showed a significant difference between groups, indicating that patients in the chronic stage still process information slower than controls. Within the patient group, patients with and without frontal focal lesions were also compared on executive and attention tests. No differences were found with respect to the latter. However, patients with frontal lesions performed worse on a measure of the Executive Route Finding task. It is concluded that patients with CHI, especially when they have frontal damage, have to rely more heavily on externally provided cues, but this dysexecutive problem can only be demonstrated in tasks that resemble daily life tasks by providing very little structure.

Recovery in 60 patients with a closed-head injury (CHI) in the first year posttrauma was assessed repeatedly with a series of attention tests. A matched group of healthy subjects was tested at the same intervals to allow us to control for practice effects. The results of a multilevel analysis for longitudinal data show retest effects in all but one of the tests. Patients performed more poorly on all tests, but their results on each test appeared to show recovery over time. The indicator of recovery was an improvement in test performance that was greater than the retest effect shown by the controls. On most tests, the performance of the more severely injured patients was initially worse, but showed more recovery over time. Test results differed with respect to changes over time, sensitivity to severity of injury, and subject specific characteristics like age and vocational level. Recovery rate was not related to age or vocational status. Despite their recovery, the patient group was still impaired 1 year posttrauma on all tests sensitive to mental slowness. Outcome after 1 year, scored on a modified Glasgow Outcome Scale, was predicted to a small extent by PTA duration and initial performance on the RT-Distraction task. Return to work 2 to 5 years posttrauma was predicted by initial performance and improvement over time on the Stroop Color Word Test.

The performance of a group of 60 severely closed-head-injured patients in the subacute stage of recovery on a series of tests addressing focused, divided, and sustained attention, and supervisory attentional control was compared to the performance of a matched group of 60 healthy controls. Patients performed significantly worse on each test with time pressure (those addressing focused and divided attention), indicating basic slowness of information processing, and on the self-paced tasks for supervisory attentional control. No indication was found of a sustained attention deficit. In a subsequent analysis the influence of the demonstrated slowness of information processing and other possibly confounding cognitive factors was controlled for by means of covariance analyses. This resulted in a disappearance of group differences on tests for focused and divided attention. The only difference that remained concerned a test for supervisory attentional control.

This study describes the performance of three groups of subjects on a pictorial forced-recognition task, the Hundred Pictures Test. The aim was to determine whether subjects with memory deficits (elderly and closed-head-injured subjects) would perform as well as healthy young subjects, both on immediate and very long-term recognition. The results indicate that memory for complex meaningful pictures is spared in subjects with an otherwise impaired memory, and that despite increasing forgetting rates with increasing retention intervals (up to 27 weeks), still no differences are found between performance of these subjects and healthy young controls. It will be discussed how this result might be interpreted.