Performance Deficits In Patients Research Articles

The impact of reward and punishment sensitivity on memory and executive performance in individuals with amnestic mild cognitive impairment

Amnestic mild cognitive impairment (aMCI) is defined by memory impairment but executive function (EF) deficits could be also a common feature. This study examined the underlying neurocognitive processes associated with executive function (EF) deficits in patients with aMCI using the Wisconsin Card Sorting Test (WCST) and computational modeling. Forty-two patients with aMCI and thirty-eight matched Controls performed the WSCT and underwent neurocognitive assessment. The Attentional Learning Model was applied the WCST. Patients with aMCI demonstrated deficits in feedback-learning. More specifically, patients showed increased Reward-Sensitivity and reduced Punishment-Sensitivity. These alterations were associated with poor WSCT performance and deficits in EF and Memory. Goal-directed deficits in aMCI, as observed in the WCST, are associated with difficulties in updating attention after feedback as its changes too rapidly following positive feedback and too slowly following negative feedback. Consequently, memory and EF deficits interact and reinforce each other generating performance deficits in patients with aMCI.

Central nervous system microbleeds in the acute phase are associated with structural integrity by DTI one year after mild traumatic brain injury: A longitudinal study

IntroductionSeveral imaging modalities are under investigation to unravel the pathophysiological mystery of delayed performance deficits in patients after mild traumatic brain injury (mTBI). Although both imaging and neuropsychological studies have been conducted, only few data on longitudinal correlations of diffusion tensor imaging (DTI), susceptibility weighted imaging (SWI) and extensive neuropsychological testing exist. MethodsMRI with T1- and T2-weighted, SWI and DTI sequences at baseline and 12 months of 30 mTBI patients were compared with 20 healthy controls. Multiparametric assessment included neuropsychological testing of cognitive performance and post-concussion syndrome (PCS) at baseline, 3 and 12 months post-injury. Data analysis encompassed assessment of cerebral microbleeds (Mb) in SWI, tract-based spatial statistics (TBSS) and voxel-based morphometry (VBM) of DTI (VBM-DTI). Imaging markers were correlated with neuropsychological testing to evaluate sensitivity to cognitive performance and post-concussive symptoms. ResultsPatients with Mb in SWI in the acute phase showed worse performance in several cognitive tests at baseline and in the follow-ups during the chronic phase and higher symptom severity in the post concussion symptom scale (PCSS) at twelve months post-injury. In the acute phase there was no statistical difference in structural integrity as measured with DTI between mTBI patients and healthy controls. At twelve months post-injury, loss of structural integrity in mTBI patients was found in nearly all DTI indices compared to healthy controls. ConclusionsPresence of Mb detected by SWI was associated with worse cognitive outcome and persistent PCS in mTBI patients, while DTI did not prove to predict neuropsychological outcome in the acute phase.

Attention Contributes to Arithmetic Deficits in New-Onset Childhood Absence Epilepsy.

Neuropsychological studies indicate that new-onset childhood absence epilepsy (CAE) is associated with deficits in attention and executive functioning. However, the contribution of these deficits to impaired academic performance remains unclear. We aimed to examine whether attention and executive functioning deficits account for the academic difficulties prevalent in patients with new-onset CAE. We analyzed cognitive performance in several domains, including language, mathematics, psychomotor speed, spatial ability, memory, general intelligence, attention, and executive functioning, in 35 children with new-onset CAE and 33 control participants. Patients with new-onset CAE exhibited deficits in mathematics, general intelligence, attention, and executive functioning. Furthermore, attention deficits, as measured by a visual tracing task, accounted for impaired arithmetic performance in the new-onset CAE group. Therefore, attention deficits, rather than impaired general intelligence or executive functioning, may be responsible for arithmetic performance deficits in patients with new-onset CAE.

A Computerized Test of Design Fluency.

Tests of design fluency (DF) assess a participant’s ability to generate geometric patterns and are thought to measure executive functions involving the non-dominant frontal lobe. Here, we describe the properties of a rapidly administered computerized design-fluency (C-DF) test that measures response times, and is automatically scored. In Experiment 1, we found that the number of unique patterns produced over 90 s by 180 control participants (ages 18 to 82 years) correlated with age, education, and daily computer-use. Each line in the continuous 4-line patterns required approximately 1.0 s to draw. The rate of pattern production and the incidence of repeated patterns both increased over the 90 s test. Unique pattern z-scores (corrected for age and computer-use) correlated with the results of other neuropsychological tests performed on the same day. Experiment 2 analyzed C-DF test-retest reliability in 55 participants in three test sessions at weekly intervals and found high z-score intraclass correlation coefficients (ICC = 0.79). Z-scores in the first session did not differ significantly from those of Experiment 1, but performance improved significantly over repeated tests. Experiment 3 investigated the performance of Experiment 2 participants when instructed to simulate malingering. Z-scores were significantly reduced and pattern repetitions increased, but there was considerable overlap with the performance of the control population. Experiment 4 examined performance in veteran patients tested more than one year after traumatic brain injury (TBI). Patients with mild TBI performed within the normal range, but patients with severe TBI showed reduced z-scores. The C-DF test reliably measures visuospatial pattern generation ability and reveals performance deficits in patients with severe TBI.

Episodic memory impairments in bipolar disorder are associated with functional and structural brain changes.

We combined multimodal functional magnetic resonance imaging (fMRI) and structural magnetic resonance imaging to probe abnormalities in brain circuits underpinning episodic memory performance deficits in patients with bipolar disorder (BD). We acquired whole-brain fMRI data in 21 patients with BD and a matched group of 20 healthy controls during a non-verbal episodic memory task, using abstract shapes. We also examined density of gray matter, using voxel-based morphometry (VBM), and integrity of connecting fiber tracts, using diffusion tensor imaging (DTI) and tract-based spatial statistics, for areas with significant activation differences. Patients with BD remembered less well than controls which shapes they had seen and had lower activation levels during the encoding stage of the task in the anterior cingulate gyrus, the precuneus/cuneus bilaterally, and the left lingual gyrus, and higher activation levels during the retrieval stage in the left temporo-parietal junction. Patients with BD showed reduced gray matter volumes in the left anterior cingulate, the precuneus/cuneus bilaterally, and the left temporo-parietal region in comparison with controls. DTI revealed increased radial, axial, and mean diffusivity in the left superior longitudinal fascicle in patients with BD compared with controls. Changes in task-related activation in frontal and parietal areas were associated with poorer episodic memory in patients with BD. Compared with data from single imaging modalities, integration of multimodal neuroimaging data enables the building of more complete neuropsychological models of mental disorders.

Impact of gray matter reductions on theory of mind abilities in patients with schizophrenia

To identify the brain regions involved in the interpretation of intentional movement by patients with schizophrenia, we investigated the association between cerebral gray matter (GM) volumes and performance on a theory of mind (ToM) task using voxel-based morphometry. Eighteen patients with schizophrenia and thirty healthy controls participated in the study. Participants were given a moving shapes task that employs the interpretation of intentional movement. Verbal descriptions were rated according to intentionality. ToM performance deficits in patients were found to be positively correlated with GM volume reductions in the superior temporal sulcus and medial prefrontal cortex. Our findings confirm that divergent brain regions contribute to mentalizing abilities and that GM volume reductions impact behavioral deficits in patients with schizophrenia.

Impact of cognitive performance on the reproducibility of fMRI activation in schizophrenia.

Longitudinal functional magnetic resonance imaging (fMRI) studies in patients with schizophrenia allow exploration of the course of the illness and brain activity after therapy. A crucial question, however, is whether fMRI findings are reliable, because they can be affected by performance deficits in patients with schizophrenia. Our aim was to evaluate the reproducibility of fMRI activations in highly integrated language areas in patients with schizophrenia, taking into account task performance. Ten patients with schizophrenia and 10 matched healthy controls were scanned twice, 21 months apart, while performing a story comprehension task. The reproducibility of the activations in each participant was evaluated globally by the percentage of spatial overlap between the 2 sessions and locally by a voxel-wise computation of the between-session relative standard deviation. We performed between-group comparisons both with and without the inclusion of comprehension scores (measuring task performance) as a covariate. On average, patients with schizophrenia had significantly lower comprehension scores than controls (4.5/12 v. 7.8/12, p = 0.002). The mean spatial overlap between fMRI sessions was 30.6% in the patient group and 47.0% in the control group (p = 0.017). Locally, the lower reproducibility in patients was most prominent in the left posterior middle temporal gyrus, inferior frontal gyrus and medial prefrontal cortex (p < 0.001 uncorrected for multiple comparisons). Comprehension scores were positively correlated with both reproducibility measures in patients (overlap: r = 0.82, p = 0.004; relative standard deviation: several significant clusters at p < 0.001). When we included the comprehension scores as a covariate, most of the local between-group differences in reproducibility were removed, and the difference in overlap was not significant. Owing to the small sample size, we could not investigate the impact of clinical subtypes and different types of medications on reproducibility. Our findings suggest that the greater variability in activation in patients with schizophrenia compared with controls concerns high-level areas and is mainly attributable to deficient task performance. Consequently, cognitive performance must be carefully controlled when longitudinal fMRI studies are undertaken.

Searching for the daytime impairments of primary insomnia

Primary insomnia is a sleep disorder where the subjective complaint of initiating or maintaining sleep, or the experience of sleep that is non-refreshing, cannot be directly attributed to a comorbid medical or psychiatric disorder. For a diagnosis of primary insomnia, a patient must also report that the nighttime sleep disturbance is impacting upon daytime functioning. Yet, while subjective complaints of impaired wake-time functioning are well documented, consistent objective evidence of these impairments has proved elusive, particularly with regard to cognitive functioning. We aimed to review the body of literature examining neurobehavioural impairments in primary insomnia to identify which cognitive domains appear to be most consistently impaired in this group. The relatively few studies that have investigated neurobehavioural performance deficits in patients with primary insomnia have produced inconsistent and sometimes conflicting findings. It is suggested that methodological limitations, including heterogeneous test populations, variable testing protocols and conditions as well as unsuitable cognitive tasks have contributed to our inability to describe unequivocally the daytime impairments associated with insomnia. Based on our review, it appears that the deficits associated with insomnia are relatively subtle and may be qualitatively different to those that result from other sleep disorders and from imposed sleep deprivation. Attention tasks, which have a high cognitive load, and working memory tasks appear to show performance deficits more often than not in insomnia patients. It is important to more definitively characterise the daytime impairments associated with primary insomnia so that the efficacy of treatments to remedy the wake-time consequences of the disorder, in addition to the nighttime symptoms, can be investigated.

Divergent Approaches Converge on Frontal Lobe Dysfunction in Schizophrenia

Divergent Approaches Converge on Frontal Lobe Dysfunction in Schizophrenia

Functional Performance Deficits in Patients With CAI: Validity of the Multiple Hop Test

To investigate the reliability and validity of a functional performance test in patients with chronic ankle instability (CAI). Cross-sectional study. All tests were conducted in the practice room of the physical therapy department of the Vrije Universiteit Brussel. Twenty-nine healthy subjects and 29 patients with CAI were selected. For the main outcome measurements, participants performed a multiple hop test two times, within a 1-week time interval. Subjects hopped on 10 different tape markers and had to try to avoid making any postural correction. Only when subjects stood still were they allowed to continue hopping. The time needed to complete the test and VAS scores for the perceived difficulty were assessed. In unstable ankles, ICCs of time values were >0.90 (SEM = 2.3 seconds); Spearman rho values of VAS scores were >0.80. When hopping on their unstable ankles, patients (41.1 +/- 12.6 seconds) needed significantly more time to complete the test than healthy subjects (31.4 +/- 5.0 seconds; test: P = 0.000; retest: P = 0.002) or when compared with their unaffected contralateral ankles (38.0 +/- 7.1 seconds; test: P = 0.047; retest: P = 0.009). Only with respect to the dominant ankles, patients (median = 64 mm) perceived the test as significantly more difficult than did healthy subjects (median = 37 mm; test: P = 0.018; retest: P = 0.002). VAS scores of unstable ankles in patients (median = 50 mm) were significantly higher than their contralateral, unaffected ankles (median = 30 mm; test: P = 0.001; retest: P = 0.002). The multiple hop test is a reliable test demonstrating functional performance deficits in patients with CAI.

Basal ganglia lesions and psychological analyses of the control of voluntary movement.

Psychological accounts of the voluntary control of movement recognize the contribution of perceptual and decision processes as well as processes such as motor memory and timing that are more obviously a part of motor control. A model including these and other components is outlined in relation to tracking, a task that has often been used to study human perceptual-motor performance. The need for experimental control in addressing such multi-process models is emphasized. A number of studies of perceptual-motor performance deficits in patients with Parkinson's disease are reviewed. The methods by which the studies relate the behavioural data to the hypothesized underlying processes may be broadly grouped according to whether they use a subtractive logic or take a decompositional approach. These studies suggest that the basal ganglia play a role in the activation of pre-planned movement.