Recovery from apraxic deficits and its neural correlate.

BACKGROUND AND OBJECTIVE: Apraxia is a deficit of motor cognition leading to difficulties in actual tool use, imitation of gestures, and pantomiming object use. To date, little data exist regarding the recovery from apraxic deficits after stroke, and no statistical lesion mapping study investigated the neural correlate of recovery from apraxia. Accordingly, we here examined recovery from apraxic deficits, differential associations of apraxia task (imitation vs. pantomime) and effector (bucco-facial vs. limb apraxia) with recovery, and the underlying neural correlates. METHODS: We assessed apraxia in 39 patients with left hemisphere (LH) stroke both at admission and approximately 11 days later. Furthermore, we collected clinical imaging data to identify brain regions associated with recovery from apraxic deficits using voxel-based lesion-symptom mapping (VLSM). RESULTS: Between the two assessments, a significant recovery from apraxic deficits was observed with a tendency of enhanced recovery of limb compared to bucco-facial apraxia. VLSM analyses revealed that within the lesion pattern initially associated with apraxia, lesions of the left insula were associated with remission of apraxic deficits, whereas lesions to the (inferior) parietal lobe (IPL; supramarginal and angular gyrus) and the superior longitudinal fasciculus (SLF) were associated with persistent apraxic deficits. CONCLUSIONS: Data suggest that lesions affecting the core regions (and white matter) of the fronto-parietal praxis network cause more persistent apraxic deficits than lesions affecting other regions (here: the left insula) that also contribute to motor cognition and apraxic deficits.

[A New Diagnostic Tool for Apraxia in Patients with Right-Hemisphere Stroke: The Revised Cologne Apraxia Screening (KAS-R)]. / Das revidierte Kölner Apraxie-Screening (KAS-R) als diagnostisches Verfahren für Patienten mit rechtshemisphärischem Schlaganfall.

The Cologne Apraxia Screening (KAS) was developed to diagnose apraxia following left-hemisphere (LH) stroke. The present study aims at developing a diagnostic tool for patients with right-hemisphere (RH) stroke (KAS-R) by modifying the test material of the KAS and reducing the test items based on psychometric analyses.A total of 100 patients with RH stroke and 77 healthy control participants were tested. Psychometric analyses led to the exclusion of 8 KAS items. The final KAS-R, consisting of 12 items, shows good internal consistency (α = 0.795) as well as high sensitivity (79.4 %) and specificity (84.4 %). Applying a cut-off value of ≤ 46 (out of 48) points, 39 RH stroke patients were diagnosed with apraxia. Significant correlations were found between the KAS-R and an imitation test as well as expert ratings, indicating high construct validity. The results suggest that the KAS-R is a reliable and valid diagnostic tool for apraxic deficits after RH stroke.

Stress-stimulated volitional coping competencies and depression in multiple sclerosis.

OBJECTIVE: The present study examined the relationship between volitional modes of coping (self-regulation, volitional inhibition, and self-control) and depression in individuals with multiple sclerosis. METHODS: A cross-sectional study of 121 participants aged 22-60 years with clinically defined MS who were consecutively admitted to a neurological rehabilitation center during a 23-month period. Correlation analyses and hierarchical regressions were conducted to evaluate the predictive value of volitional competencies (Volitional Components Questionnaire, short form, VCQ-S) on depression (Centre for Epidemiologic Studies Depression Scale, CES-D), while controlling for demographic (age, gender, and education) and certain clinical variables (Expanded Disability Status Scale, EDSS; disease duration; and Modified Fatigue Impact Scale, MFIS). RESULTS: Hierarchical regression analyses of depression revealed a model in which 68% of the variance in the CES-D was explained by daily stress situations (VCQ-S), self-regulation (VCQ-S), fatigue (MFIS), and education. However, when the analysis included only participants who had scored above the cut-off of the CES-D (n=42), the VCQ-S factor volitional inhibition seemed to play a more relevant part in depression. In particular, the VCQ-S scales stimulation of self-access, stimulation of volitional inhibition, self-motivation, and emotional perseverance/state orientation after failure appear to be valuable predictors on CES-D. CONCLUSIONS: The results suggest that personality-accentuated volitional coping competencies elicited by daily stressful situations could be a relevant factor for depressive mood states in individuals with MS. However, to clarify the exact relationships of this rather circular framework, longitudinal study designs with objective measurements and a stronger focus on MS-specific stressors are needed.

Visual extinction in relation to visuospatial neglect after right-hemispheric stroke: quantitative assessment and statistical lesion-symptom mapping.

BACKGROUND: Visual neglect and extinction are two common neurological syndromes in patients with right-hemispheric brain damage. Whether and how these two syndromes are associated or share common neural substrates is still a matter of debate. METHODS: To address these issues, the authors investigated 56 patients with right-hemispheric stroke with a novel diagnostic test to detect extinction and neglect. In this computerised task, subjects had to respond to target stimuli in uni- and bilateral stimulation conditions with detection probabilities being assessed. A cluster-analytical approach identified 18 patients with neglect and 13 patients with extinction. Statistical lesion-symptom mapping analyses with measures for extinction and neglect were performed. RESULTS: Extinction and neglect co-occurred in a subset of patients but were also observed independently from each other, thereby constituting a double dissociation. Lesions within the right inferior parietal cortex were significantly associated with the severity of visual extinction. Visuospatial neglect was related to damage of fronto-parietal brain regions, with parieto-occipital areas affecting line bisection and dorsal fronto-parietal areas affecting cancellation task performance, respectively. CONCLUSION: Quantifying lesion-induced symptoms with this novel paradigm shows that extinction and neglect are dissociable syndromes in patients with right-hemispheric stroke. Furthermore, extinction and neglect can be related to differential neural substrates, with extinction being related to focal brain damage within the right inferior parietal cortex.