Rahel Schumacher

Theta burst stimulation reduces disability during the activities of daily living in spatial neglect

Left-sided spatial neglect is a common neurological syndrome following right-hemispheric stroke. The presence of spatial neglect is a powerful predictor of poor rehabilitation outcome. In one influential account of spatial neglect, interhemispheric inhibition is impaired and leads to a pathological hyperactivity in the contralesional hemisphere, resulting in a biased attentional allocation towards the right hemifield. Inhibitory transcranial magnetic stimulation can reduce the hyperactivity of the contralesional, intact hemisphere and thereby improve spatial neglect symptoms. However, it is not known whether this improvement is also relevant to the activities of daily living during spontaneous behaviour. The primary aim of the present study was to investigate whether the repeated application of continuous theta burst stimulation trains could ameliorate spatial neglect on a quantitative measure of the activities of daily living during spontaneous behaviour. We applied the Catherine Bergego Scale, a standardized observation questionnaire that can validly and reliably detect the presence and severity of spatial neglect during the activities of daily living. Eight trains of continuous theta burst stimulation were applied over two consecutive days on the contralesional, left posterior parietal cortex in patients suffering from subacute left spatial neglect, in a randomized, double-blind, sham-controlled design, which also included a control group of neglect patients without stimulation. The results showed a 37% improvement in the spontaneous everyday behaviour of the neglect patients after the repeated application of continuous theta burst stimulation. Remarkably, the improvement persisted for at least 3 weeks after stimulation. The amelioration of spatial neglect symptoms in the activities of daily living was also generally accompanied by significantly better performance in the neuropsychological tests. No significant amelioration in symptoms was observed after sham stimulation or in the control group without stimulation. These results provide Class I evidence that continuous theta burst stimulation is a viable add-on therapy in neglect rehabilitation that facilitates recovery of normal everyday behaviour.

Theta Burst Stimulation Over the Right Broca's Homologue Induces Improvement of Naming in Aphasic Patients

Background and Purpose— Improvements of language production in aphasic patients have been reported following repeated 1-Hz transcranial magnetic stimulation over the nondamaged right hemisphere. Most studies examined aphasic patients in the chronic phase. The effect of transcranial magnetic stimulation application in acute or subacute patients has not been systematically studied. We aimed to evaluate whether continuous theta burst stimulation, an inhibitory protocol with a shorter application time than the common 1-Hz protocol, is able to improve naming performance in aphasic patients in different poststroke phases. Methods— Eighteen right-handed aphasic patients performed a picture naming task and a language independent alertness test before and after the application of theta burst stimulation over the intact right Brocas homologue localized by the 10–20 electroencephalogram system in a randomized, sham-controlled, crossover trial. Results— We found that naming performance was significantly better, and naming latency was significantly shorter, after theta burst stimulation than after the sham intervention. Patients who responded best were in the subacute phase after stroke. Conclusions— This setting with the short theta burst stimulation application time and the simple stimulation localization procedure is suitable for clinical purposes.

Trajectory of disability and quality-of-life in non-geriatric and geriatric survivors after severe traumatic brain injury.

ABSTRACT Objective: The objective was to investigate disability and health-related quality-of-life (HRQoL) 3, 6 and 12 months after traumatic brain injury (TBI) in non-geriatric (≤ 65 years) and geriatric patients (> 65 years). Methods: Patients ≥ 16 years who sustained a severe TBI (Abbreviated Injury Scale of the head region > 3) were included in this prospective, multi-centre study. Outcome measures were Glasgow Outcome Scale Extended (GOSE; disability), SF-12 (HRQoL). Mixed linear model analyses were performed. Results: Three hundred and fifty-one patients (median age = 50 years; interquartile range (IQR) = 27–67) were included; 73.2% were male and 27.6% were geriatric patients. Median GOSE at 3, 6 and 12 months was 5 (IQR = 3–7), 6 (IQR = 4–8) and 7 (IQR = 5–8); this increase (slopetime = 0.22, p < 0.0001) was age dependent (slopeage*time = –0.06, p = 0.003). Median SF-12 physical component scale score at 3, 6 and 12 months was 42.1 (IQR = 33.6–50.7), 46.6 (IQR = 37.4–53.9) and 50.4 (IQR = 39.2–55.1); this increase (slopetime = 1.52, p < 0.0001) was not age dependent (slopeage*time = –0.30, p = 0.083). SF-12 mental component scale scores were unchanged. Conclusions: Disability decreased and HRQoL improved after TBI between 3–12 months. In geriatric patients this improvement was relevant for HRQoL only.

Cue Recognition and Integration – Eye Tracking Evidence of Processing Differences in Sentence Comprehension in Aphasia

Purpose We aimed at further elucidating whether aphasic patients’ difficulties in understanding non-canonical sentence structures, such as Passive or Object-Verb-Subject sentences, can be attributed to impaired morphosyntactic cue recognition, and to problems in integrating competing interpretations. Methods A sentence-picture matching task with canonical and non-canonical spoken sentences was performed using concurrent eye tracking. Accuracy, reaction time, and eye tracking data (fixations) of 50 healthy subjects and 12 aphasic patients were analysed. Results Patients showed increased error rates and reaction times, as well as delayed fixation preferences for target pictures in non-canonical sentences. Patients’ fixation patterns differed from healthy controls and revealed deficits in recognizing and immediately integrating morphosyntactic cues. Conclusion Our study corroborates the notion that difficulties in understanding syntactically complex sentences are attributable to a processing deficit encompassing delayed and therefore impaired recognition and integration of cues, as well as increased competition between interpretations.

ERP correlates of superordinate category activation

The human semantic network is hierarchically organized, containing superordinate, basic and subordinate levels. Various impairments are thought to be connected with abnormal access to superordinate concepts. We devised an ERP paradigm to examine the activation of superordinate versus otherwise related concepts in 20 healthy participants. Following the presentation of a typical category member an arrow indicated whether the appropriate superordinate category had to be generated (categorization task) or an otherwise related word (relation task). To control task execution, a second word was presented for which a match-mismatch-judgment was required. Reaction times, accuracy rates and ERPs after the second word showed that participants successfully accessed the superordinate category name and that verification in the categorization task was faster and easier than in the relation task. Comparison of ERPs after the arrow revealed topographical, Global Field Power (GFP), and onset latency differences between the two tasks and thus indicated the involvement of at least partially different neural generators. Source localization analysis confirmed that brain regions were activated that were also identified in previous experiments with semantic task. The paradigm seems to be suitable for further examination of superordinate activation processes and evaluation of impairments such as thought disorders in schizophrenic patients.

Perception of co-speech gestures in aphasic patients: A visual exploration study during the observation of dyadic conversations

BACKGROUND Co-speech gestures are part of nonverbal communication during conversations. They either support the verbal message or provide the interlocutor with additional information. Furthermore, they prompt as nonverbal cues the cooperative process of turn taking. In the present study, we investigated the influence of co-speech gestures on the perception of dyadic dialogue in aphasic patients. In particular, we analysed the impact of co-speech gestures on gaze direction (towards speaker or listener) and fixation of body parts. We hypothesized that aphasic patients, who are restricted in verbal comprehension, adapt their visual exploration strategies. METHODS Sixteen aphasic patients and 23 healthy control subjects participated in the study. Visual exploration behaviour was measured by means of a contact-free infrared eye-tracker while subjects were watching videos depicting spontaneous dialogues between two individuals. Cumulative fixation duration and mean fixation duration were calculated for the factors co-speech gesture (present and absent), gaze direction (to the speaker or to the listener), and region of interest (ROI), including hands, face, and body. RESULTS Both aphasic patients and healthy controls mainly fixated the speakers face. We found a significant co-speech gesture × ROI interaction, indicating that the presence of a co-speech gesture encouraged subjects to look at the speaker. Further, there was a significant gaze direction × ROI × group interaction revealing that aphasic patients showed reduced cumulative fixation duration on the speakers face compared to healthy controls. CONCLUSION Co-speech gestures guide the observers attention towards the speaker, the source of semantic input. It is discussed whether an underlying semantic processing deficit or a deficit to integrate audio-visual information may cause aphasic patients to explore less the speakers face.

Predictors of inpatient (neuro)rehabilitation after acute care of severe traumatic brain injury: An epidemiological study

Abstract Objective: To describe the discharge destination of patients with severe traumatic brain injury (sTBI) after acute care. To identify predictors associated with inpatient rehabilitation (vs discharge home) and to identify predictors associated with neurorehabilitation (vs general rehabilitation). Methods: A national, multi-centre, prospective study with adult survivors after sTBI (abbreviated injury scale head score > 3). Univariate and multivariate logistic regression models included patient characteristics, pre-injury conditions, initial neuro-physiological assessment, trauma mechanisms, severity of TBI and pre-hospital conditions to find predictors of discharge destination. Results: Out of the 566 included patients, 341 (60%) were referred to inpatient rehabilitation, thereof 249 (73%) to neurorehabilitation; 225 (40%) were discharged home or to a nursing home. Lower scores on the Glasgow Coma Scale at admission/at 14 days, higher injury severity scores and older age were predictors for inpatient rehabilitation. Younger age and male gender were predictors for neurorehabilitation. Conclusions: Patients’ pathways after acute care are not only determined by the severity of their brain injury, but also by their overall injury severity and socio-biological factors. More than half of the patients after sTBI are not discharged to specialized inpatient neurorehabilitation and, therefore, efforts should be taken to optimize post-acute care.

Different visual exploration of tool-related gestures in left hemisphere brain damaged patients is associated with poor gestural imitation

According to the direct matching hypothesis, perceived movements automatically activate existing motor components through matching of the perceived gesture and its execution. The aim of the present study was to test the direct matching hypothesis by assessing whether visual exploration behavior correlate with deficits in gestural imitation in left hemisphere damaged (LHD) patients. Eighteen LHD patients and twenty healthy control subjects took part in the study. Gesture imitation performance was measured by the test for upper limb apraxia (TULIA). Visual exploration behavior was measured by an infrared eye-tracking system. Short videos including forty gestures (20 meaningless and 20 communicative gestures) were presented. Cumulative fixation duration was measured in different regions of interest (ROIs), namely the face, the gesturing hand, the body, and the surrounding environment. Compared to healthy subjects, patients fixated significantly less the ROIs comprising the face and the gesturing hand during the exploration of emblematic and tool-related gestures. Moreover, visual exploration of tool-related gestures significantly correlated with tool-related imitation as measured by TULIA in LHD patients. Patients and controls did not differ in the visual exploration of meaningless gestures, and no significant relationships were found between visual exploration behavior and the imitation of emblematic and meaningless gestures in TULIA. The present study thus suggests that altered visual exploration may lead to disturbed imitation of tool related gestures, however not of emblematic and meaningless gestures. Consequently, our findings partially support the direct matching hypothesis.

Bilateral neglect after bihemispheric strokes

Dario Cazzoli , Rahel Schumacher , Uli Baas , René M. Müri , Roland Wiest , Stephan Bohlhalter , Christian W. Hess a,b and Thomas Nyffeler * Perception and Eye Movement Laboratory, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland b Perception and Eye Movement Laboratory, Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Switzerland c Institute of Diagnostic and Interventional Neuroradiology, Department of Radiology, Neuroradiology and Nuclear Medicine, Inselspital, Bern University Hospital, and University of Bern, Switzerland

Comprehension of co-speech gestures in aphasic patients: An eye movement study

Background Co-speech gestures are omnipresent and a crucial element of human interaction by facilitating language comprehension. However, it is unclear whether gestures also support language comprehension in aphasic patients. Using visual exploration behavior analysis, the present study aimed to investigate the influence of congruence between speech and co-speech gestures on comprehension in terms of accuracy in a decision task. Method Twenty aphasic patients and 30 healthy controls watched videos in which speech was either combined with meaningless (baseline condition), congruent, or incongruent gestures. Comprehension was assessed with a decision task, while remote eye-tracking allowed analysis of visual exploration. Results In aphasic patients, the incongruent condition resulted in a significant decrease of accuracy, while the congruent condition led to a significant increase in accuracy compared to baseline accuracy. In the control group, the incongruent condition resulted in a decrease in accuracy, while the congruent condition did not significantly increase the accuracy. Visual exploration analysis showed that patients fixated significantly less on the face and tended to fixate more on the gesturing hands compared to controls. Conclusion Co-speech gestures play an important role for aphasic patients as they modulate comprehension. Incongruent gestures evoke significant interference and deteriorate patients’ comprehension. In contrast, congruent gestures enhance comprehension in aphasic patients, which might be valuable for clinical and therapeutic purposes.