Sensorimotor, Attentional, and Neuroanatomical Predictors of Upper Limb Motor Deficits and Rehabilitation Outcome after Stroke

The rehabilitation of motor deficits following stroke relies on both sensorimotor and cognitive abilities, thereby involving large-scale brain networks. However, few studies have investigated the integration between motor and cognitive domains, as well as its neuroanatomical basis. In this retrospective study, upper limb motor responsiveness to technology-based rehabilitation was examined in a sample of 29 stroke patients (18 with right and 11 with left brain damage). Pretreatment sensorimotor and attentional abilities were found to influence motor recovery. Training responsiveness increased as a function of the severity of motor deficits, whereas spared attentional abilities, especially visuospatial attention, supported motor improvements. Neuroanatomical analysis of structural lesions and white matter disconnections showed that the poststroke motor performance was associated with putamen, insula, corticospinal tract, and frontoparietal connectivity. Motor rehabilitation outcome was mainly associated with the superior longitudinal fasciculus and partial involvement of the corpus callosum. The latter findings support the hypothesis that motor recovery engages large-scale brain networks that involve cognitive abilities and provides insight into stroke rehabilitation strategies.

Body Representation Alterations in Patients with Unilateral Brain Damage

Objective: Systematic studies about the impact of unilateral brain damage on the different body representations (body schema, body structural representation, and body semantics) are still rare. Aim of this study was to evaluate body representation deficits in a relatively large sample of patients with unilateral brain damage and to investigate the impact of right or left brain damage on body representations (BRs), independently from deficits in other cognitive processes. Method: Sixty-four patients with unilateral stroke (22 with left brain damage, LBD; 31 with right brain damage without neglect, RBD-N; 11 with right brain damage with neglect, RBD+N) and 41 healthy individuals underwent a specific battery including BR as well as control tasks. Results: In more than a third of the sample, selective (37.5%) and pure (31%) deficits of BR were presented and equally distributed among the different BRs (˜10% for each representation), with selective (27.2%) and pure (22.7%) body schema deficit mainly presented after left brain damage. As a group, patients with unilateral brain damage, independently of the side of lesion (LBD, RBD-N, RBD+N), had significantly worse performance on body structural representation with respect to healthy individuals, whereas LBD had numerically worse performance on body schema with respect to healthy individuals and RBD-N. No significant differences among groups were found on body semantics. Conclusion: BR deficits are not a rare consequence of unilateral brain damage and are independent of a more general cognitive dysfunction. Accordingly, the need for an accurate assessment and specific neuropsychological training in clinical settings is discussed.

Validity and features of spontaneous speech in acute aphasia as evaluated with the Brief Aphasia Evaluation: is fluent aphasia more severe than nonfluent aphasia?

ABSTRACT Purpose To explore the relationship between the two components of spontaneous speech in the Brief Aphasia Evaluation (BAE) and the rest of the scale represented by its three main factors: The Expression, Comprehension, and Complementary factors. Methods BAE has proven validity and reliability. The evaluation of spontaneous speech in this scale comprises two components: Performance Rank (score: 0-3) and Type of Disorder (Fluency [F], Content [C], or Mixed [FC]) when rank < 3. Sixty-seven patients with left brain damage and 30 demographically matched healthy participants (HP) were studied. It was analyzed the correlation between Performance Rank and the three BAE factors and, recoding 3 as 0 and < 3 as 1, the sensitivity/specificity of this component for each factor. The effect of Type of Disorder on the three factors was analyzed. Results 1) Performance Rank: Correlations of 0.84 (Expression), 0.81 (Comprehension), and 0.76 (Complementary) were observed, with a sensitivity and specificity ≥ 78% for any factor; 2) Type of Disorder: The performance significantly decreased from FC to C and from C to F in Expression (FC < C < F), from FC to C and from FC to F also in Comprehension and Complementary, from patients with any type of disorder to HP. Conclusion Performance Rank was a relevant indicator of aphasia by its consistency with valid and comprehensive dimensions of acute language impairments. A degree difference between F and C was observed, being F a milder disorder; i.e., fluency problems were less severe than retrieval or anomia ones.

Towards a Dynamic Assessment of Unilateral Spatial Neglect

Background: The traditional paper and pencil tests are often inadequate to detect the mild forms of Unilateral Spatial Neglect (USN). Objective: To verify the effectiveness of a touchscreen-based cancellation test in assessing individuals with USN. Methods: Seven individuals, six with right and one with left brain damage, who showed moderate to severe USN at admission, were involved in the study. Besides classic paper and pencil tests, participants were presented with a new, “user-friendly”, device consisting of an interactive “table” that integrates the principles of ecologic interaction and sophisticated technology. Such a touch screen table made possible to analyse the spatial and temporal evolution of the participants’ performance, providing a set of indices related to “how” the different tasks have been fulfilled, rather than simple raw scores. Results: This new technological approach turned out to be much more sensitive than the classic paper and pencil tests to detect the slightest forms of USN. In particular, while four out of the seven participants, performed flawless on the papery version of the Albert’s test, all of them made errors on the technological versions of the same Albert’s test. Finally, under all the different experimental conditions, participants achieved always a better performance when asked to erase rather than mark stimuli. Conclusion: Such a device has a potential in the ecological assessment of USN as well as in monitoring its evolution. Although in need of further substantiation, our findings further support the need to go beyond the traditional paper and pencil tests in the assessment of USN. The information provided by a more dynamic approach seems to be relevant for both clinical and research purposes.