Impaired Performance In Patients Research Articles

Impaired performance of patients with writer’s cramp in complex fine motor tasks

ObjectiveWriter’s cramp (WC) is a task-specific focal dystonia. WC is characterized by involuntary contractions of muscles of the hand and arm during handwriting, resulting in impaired writing with exaggerated finger forces. The generalization of symptoms to other fine motor tasks is widely discussed. The aim of the study was to determine affected fine motor aspects with an extensive testing battery. MethodsTwelve people with WC and twelve healthy controls were examined. Performance in the Jebsen-Taylor Hand Function Test, Nine-Hole-Peg Test and 2-point discrimination was evaluated. To analyze object manipulation skills, we examined grip forces, temporal measures and other aspects of force control during (1) lifting actions with variations of weight and surface (2) cyclic movements (3) visuomotor tracking (4) fast force changes and (5) grip strength. In addition, correlation between the dependent variables of the fine motor tasks and the handwriting deficits was assessed. ResultsWC patients had impaired performance in the visuomotor tracking task (root mean square error (RMSE), p = 0.03 and time lag, p = 0.05) and the fast force changes (frequency, p = 0.01). There were no statistically significant group differences in the other tasks. We found a correlation between the RMSE of the tracking task and the time needed to write the test sentence (r = 0.643, p = 0.01). ConclusionWC patients revealed abnormalities in complex fine motor performance in tasks with high demands on coordination and visual components, specifically in tracking and fast force changes. SignificanceThis suggests a deficit in visuomotor integration, coordination and cognitive aspects related to movement processing particularly with respect to low forces. These insights may prove useful in the development of targeted training approaches.

Early subclinical dysfunction of right cardiac system induced by anthracycline manifested as morphological changes

Objective Both right and left ventricular function should be taken into account in the assessment of anthracycline (ATC)-induced cardiotoxicity. The aim of this study was to assess the subclinical dysfunction of right cardiac system in patients with newly diagnosed lymphoma who received ATC treatment by echocardiography. Methods A total of 74 patients with lymphoma who received ATC treatment were enrolled. Each patient underwent transthoracic echocardiographic examination before chemotherapy as well as after two, four and six cycles of ATC remedy. Right atrial (RA) and right ventricular (RV) end-diastolic area (EDA) and end-systolic area (ESA) were calculated. RV end-diastolic volume (EDV) and end-systolic volume (ESV), as well as RV ejection fraction (EF) were measured simultaneously. Tissue Doppler imaging (TDI) measurements of systolic and early or late diastolic myocardial velocities of RV free wall at tricuspid annuals were also analyzed. Two-dimensional speckle tracking echocardiography (2DSTE) was conducted to evaluate RV free wall strain along with strain rate. Results None of the echocardiographic parameters showed significant alteration after two and four cycles of chemotherapy compared with those at baseline (P>0.05). At the end of the therapy (i.e. after six cycles of ATC treatment), there was still no statistical difference on TDI data as well as 2DSTE measurements (P>0.05). An unexpected finding was that the RAEDA((6.6±1.9) cm2 vs (7.7±2.4) cm2) and RAESA ((8.8±2.5) cm2 vs (10.8±2.8) cm2) revealed obvious dilatation after six cures of the regimen compared with those at baseline (P 0.05). Conclusions Echocardiography can be used easily and noninvasively to assess right cardiac system subclinical dysfunction. ATC-induced cardiotoxicity of right cardiac system is firstly manifested as morphological changes than the measurements with novel echocardiographic techniques. In addition, RVEF expresses as a valuable parameter for assessing subtle RV impaired performance in patients with lymphoma received ATC therapy. Key words: Anthracycline; Lymphoma; Right atrial function; Right ventricular function; Echocardiography

Effects of Mental Flexibility and Motor Dysfunction on Cognitive Performance in Patients With Parkinson's Disease

Background: Parkinson's disease (PD) is a neurodegenerative disorder characterized by pervasive motor deficits, often accompanied by specific cognitive impairments, most prominently executive dysfunctions. However, it is often hard to determine whether the impaired performance of patients with PD on executive tests is the result of an executive dysfunction or whether it is due to motor difficulties. Objectives: The present study aimed to examine the relationship between cognitive inflexibility, an executive dysfunction consistently found in PD, and motor deficiencies in patients with PD using derived scores, from a common executive function test named trail making test (TMT). Patients and Methods: Fifty patients with PD and 50 demographically matched controls underwent neuropsychological examination which included TMT, part A and part B. Performance on each task was assessed and the following derived scores TMT B/A, TMT B-A/A, and TMT B-A were calculated and compared. Results: Mann-Whitney tests revealed significant group differences for the mean TMT A (P = 0.006) and TMT B (P = 0.000), which were both higher in the PD group, relative to controls. In addition, significant differences were found for one TMT product score (TMT B-A). Conclusions: The results presented a significantly lower performance of patients with PD compared to controls, indicating the presence of a mental flexibility impairment which is dissociable and independent from the motor dysfunction.

Sensorimotor Cortex Gamma-Aminobutyric Acid Concentration Correlates with Impaired Performance in Patients with MS

Abnormalities in GABA concentration [GABA] have been associated with several neuropsychiatric disorders, and research has suggested that GABA may play a role in sensorimotor cortex function. We sought to determine whether identifying a change in [GABA] within the sensorimotor cortex of patients with MS has any effect on motor function and would provide information about the adaptive/compensatory mechanisms involved in the attempt to maintain motor function during disease progression. In 19 healthy controls and 30 patients with MS, we assessed task performance with the MS Functional Composite scale and its components (T25FW test, 9HPT, and PASAT). With in vivo MR spectroscopy, we measured [GABA] in the sensorimotor cortex and determined correlations between [GABA] and task performance. We also assessed the association between [GABA] and cortical activation volume after a bilateral finger-tapping task. [GABA] was inversely correlated with 9HPT scores in patients with MS, indicating a worsening of performance with increased [GABA]. No significant correlation was observed between [GABA] and T25FW or PASAT scores. [GABA] was directly correlated with primary motor cortex activation volume after the finger-tapping task in patients with MS. These results suggest that cortical [GABA] may be a marker of function and reorganization/adaptation of cortical gray matter in MS.

The neural correlates of impaired collision avoidance in hemianopic patients

The aim of this study was to assess the brain regions associated with impaired performance in a virtual, dynamic collision avoidance task, in a group of patients with homonymous visual field defects (HVFDs) because of unilateral vascular brain lesions. Overall task performance was quantitatively assessed as the number of collisions while crossing an intersection at two levels of traffic density. Twenty-six patients were divided into two subgroups using the median split method: patients with 'performance above average' (HVFD(A), i.e. lower number of collisions) and patients with 'performance below average' (HVFD(B), i.e. higher number of collisions). In order to identify the anatomical structures that might be specifically affected in HVFD(B) patients but spared in HVFD(A) patients, overlap, subtraction and voxel-based lesion-symptom mapping analyses were performed using the MRIcron software. No significant difference in collision avoidance between patients with left- and right-hemispheric lesions was revealed. Separate lesion analysis in 12 patients with right- and 14 patients with left-hemispheric lesions showed that the cortical structures associated with impaired collision avoidance were the parieto-occipital region and posterior cingulate gyrus in the right hemisphere and the inferior occipital cortex and parts of the fusiform (occipito-temporal) gyrus in the left hemisphere. In the present collision avoidance paradigm, impaired performance of patients with right-hemispheric lesions is associated with damage in the dorsal processing stream and potential impact on the visual spatial working memory (WM), while impaired performance of patients with left-hemispheric lesions is associated with damage in the ventral stream and potential impact on the visual object WM.

Working memory, long-term memory, and medial temporal lobe function.

Early studies of memory-impaired patients with medial temporal lobe (MTL) damage led to the view that the hippocampus and related MTL structures are involved in the formation of long-term memory and that immediate memory and working memory are independent of these structures. This traditional idea has recently been revisited. Impaired performance in patients with MTL lesions on tasks with short retention intervals, or no retention interval, and neuroimaging findings with similar tasks have been interpreted to mean that the MTL is sometimes needed for working memory and possibly even for visual perception itself. We present a reappraisal of this interpretation. Our main conclusion is that, if the material to be learned exceeds working memory capacity, if the material is difficult to rehearse, or if attention is diverted, performance depends on long-term memory even when the retention interval is brief. This fundamental notion is better captured by the terms subspan memory and supraspan memory than by the terms short-term memory and long-term memory. We propose methods for determining when performance on short-delay tasks must depend on long-term (supraspan) memory and suggest that MTL lesions impair performance only when immediate memory and working memory are insufficient to support performance. In neuroimaging studies, MTL activity during encoding is influenced by the memory load and correlates positively with long-term retention of the material that was presented. The most parsimonious and consistent interpretation of all the data is that subspan memoranda are supported by immediate memory and working memory and are independent of the MTL.

Dissociating sequence learning performance in Parkinson's disease: Visuomotor sequence acquisition and pattern judgment on a serial reaction time task.

In this study, the sequence learning performance of 16 non-demented patients with Parkinson's disease (PD) was compared with 18 age-matched healthy controls on a verbal version of the serial reaction time (SRT) task intended to encapsulate both visuomotor- and judgment-linked learning processes. Visuomotor sequence performance in PD patients was closely related to baseline response speed, with robust learning demonstrated by patients who responded with comparable speed to controls but severely impaired performance in patients who responded slowly. In contrast, both fast- and slow-responding PD patients were able to successfully categorise patterns according to their sequential status, a performance that was linked to declarative memory for the sequence. The findings highlight the important role of event timing in SRT performance and are in accord with the hypothesis that, despite the important role played by the basal ganglia in motor sequence learning, basal ganglionic dysfunction may not substantially impair sequence order learning so much as the translation of sequence knowledge into rapid motor performance for some PD patients. Intact pattern judgment on the SRT experiment suggests that the integrity of the neostriatum is not essential for learning judgment-linked categorical information about sequences of temporal stimulus movement.

Patterns of prefrontal dysfunction in alcoholics with and without Korsakoff's syndrome, patients with Parkinson's disease, and patients with rupture and repair of the anterior communicating artery.

This study compared patterns of frontal-lobe dysfunction in alcoholics with Korsakoff's syndrome (KS: n = 9), non-Korsakoff alcoholics (AL: n = 28), patients with Parkinson's disease (PD: n = 18), and patients with rupture and repair of the anterior communicating artery (ACoA: n = 4) relative to healthy non-neurological control (NC) participants (n = 70). The tests administered were sensitive to functions of dorsolateral prefrontal and orbito-frontal subsystems. Measures included perseverative errors on the Wisconsin Card Sorting Test (WCST-pe), errors on object alternation (OA), errors on Trails B, number of words generated on the Controlled Oral Word Association Test (COWAT), and number of categories completed on the WCST (WCST-cc). KS patients were as impaired as AL participants on orbitofrontal measures and, on dorsolateral prefrontal measures, were impaired relative to AL participants, whose performance did not differ from controls. Patients with PD also were impaired on tests of orbitofrontal and dorsolateral prefrontal functioning but to a lesser extent than the KS patients. Moreover, most of the PD deficits were driven by the impaired performance of patients whose initial symptoms were on the right side of the body. The ACoA patients were significantly impaired on tests of orbitofrontal but not dorsolateral prefrontal functioning relative to the control group. Together, the results confirm different patterns of frontal-system impairments in patient groups having compromised frontal lobe functioning consequent to varying etiologies.

Structure and deterioration of semantic memory: a neuropsychological and computational investigation.

Wernicke (1900, as cited in G. H. Eggert, 1977) suggested that semantic knowledge arises from the interaction of perceptual representations of objects and words. The authors present a parallel distributed processing implementation of this theory, in which semantic representations emerge from mechanisms that acquire the mappings between visual representations of objects and their verbal descriptions. To test the theory, they trained the model to associate names, verbal descriptions, and visual representations of objects. When its inputs and outputs are constructed to capture aspects of structure apparent in attribute-norming experiments, the model provides an intuitive account of semantic task performance. The authors then used the model to understand the structure of impaired performance in patients with selective and progressive impairments of conceptual knowledge. Data from 4 well-known semantic tasks revealed consistent patterns that find a ready explanation in the model. The relationship between the model and related theories of semantic representation is discussed.