Intentional gaze shift to neglected space: a compensatory strategy during recovery after unilateral spatial neglect.

Unilateral spatial neglect is a common neurological syndrome following predominantly right hemispheric stroke. While most patients lack insight into their neglect behaviour and do not initiate compensatory behaviours in the early recovery phase, some patients recognize it and start to pay attention towards the neglected space. We aimed to characterize visual attention capacity in patients with unilateral spatial neglect with specific focus on cortical processes underlying compensatory gaze shift towards the neglected space during the recovery process. Based on the Behavioural Inattention Test score and presence or absence of experience of neglect in their daily life from stroke onset to the enrolment date, participants were divided into USN+‰‰+ (do not compensate, n = 15), USN+ (compensate, n = 10), and right hemisphere damage groups (no neglect, n = 24). The patients participated in eye pursuit-based choice reaction tasks and were asked to pursue one of five horizontally located circular objects flashed on a computer display. The task consisted of 25 trials with 4-s intervals, and the order of highlighted objects was randomly determined. From the recorded eye tracking data, eye movement onset and gaze shift were calculated. To elucidate the cortical mechanism underlying behavioural results, electroencephalagram activities were recorded in three USN+‰‰+, 13 USN+ and eight patients with right hemisphere damage. We found that while lower Behavioural Inattention Test scoring patients (USN+‰‰+) showed gaze shift to non-neglected space, some higher scoring patients (USN+) showed clear leftward gaze shift at visual stimuli onset. Moreover, we found a significant correlation between Behavioural Inattention Test score and gaze shift extent in the unilateral spatial neglect group (r = -0.62, P < 0.01). Electroencephalography data clearly demonstrated that the extent of increase in theta power in the frontal cortex strongly correlated with the leftward gaze shift extent in the USN+‰‰+ and USN+ groups. Our results revealed a compensatory strategy (continuous attention to the neglected space) and its neural correlates in patients with unilateral spatial neglect. In conclusion, patients with unilateral spatial neglect who recognized their own neglect behaviour intentionally focused on the neglected space as a compensatory strategy to avoid careless oversight.

Short-term effects of goal-setting focusing on the life goal concept on subjective well-being and treatment engagement in subacute inpatients: a quasi-randomized controlled trial.

OBJECTIVE: To investigate the short-term effects of the life goal concept on subjective well-being and treatment engagement, and to determine the sample size required for a larger trial. DESIGN: A quasi-randomized controlled trial that was not blinded. SETTING: A subacute rehabilitation ward. SUBJECTS: A total of 66 patients were randomized to a goal-setting intervention group with the life goal concept (Life Goal), a standard rehabilitation group with no goal-setting intervention (Control 1), or a goal-setting intervention group without the life goal concept (Control 2). INTERVENTIONS: The goal-setting intervention in the Life Goal and Control 2 was Goal Attainment Scaling. The Life Goal patients were assessed in terms of their life goals, and the hierarchy of goals was explained. The intervention duration was four weeks. MAIN MEASURES: Patients were assessed pre- and post-intervention. The outcome measures were the Hospital Anxiety and Depression Scale, 12-item General Health Questionnaire, Pittsburgh Rehabilitation Participation Scale, and Functional Independence Measure. RESULTS: Of the 296 potential participants, 66 were enrolled; Life Goal (n = 22), Control 1 (n = 22) and Control 2 (n = 22). Anxiety was significantly lower in the Life Goal (4.1 ±3.0) than in Control 1 (6.7 ±3.4), but treatment engagement was significantly higher in the Life Goal (5.3 ±0.4) compared with both the Control 1 (4.8 ±0.6) and Control 2 (4.9 ±0.5). CONCLUSIONS: The life goal concept had a short-term effect on treatment engagement. A sample of 31 patients per group would be required for a fully powered clinical trial.

Effect of anticipation triggered by a prior dyspnea experience on brain activity.

[Purpose] Oxygenated hemoglobin (oxy-Hb) concentrations in the prefrontal cortex are closely associated with dyspnea. Dyspnea is influenced not only by physical activity, but also by visual stimuli, and several studies suggest that oxy-Hb concentrations change in response to certain external stimuli. However, the effects of internal psychological states on dyspnea have not been reported. This study explored the influence of anticipation triggered by previous episodes of dyspnea on brain activity. [Subjects] The subjects were 15 healthy volunteers with a mean age of 25.0 ± 3.0 years. [Methods] The subjects were shown a variety of photographs and instructed to expect breathing resistance matched to the affective nature of the particular photograph. After viewing the images, varying intensities of breathing resistance that were identical to, easier than, or harder than those shown in the images were randomly administered to the subjects; in fact, the image and resistance were identical 33% of the time and discordant 66% of the time. [Results] The concentrations of oxy-Hb in the right medial prefrontal cortex (rMPFC) increased significantly with an inspiratory pressure that was 30% of the maximum intensity in the subjects shown a pleasant image compared to the concentrations in subjects shown an unpleasant image. Moreover, rMPFC activity was significantly correlated with the magnitude of the dyspnea experienced. [Conclusion] These results suggest that a correlation exists between increased oxy-Hb in the rMPFC and the effects of expectations on dyspnea.

Pathological structure of visuospatial neglect: A comprehensive multivariate analysis of spatial and non-spatial aspects.

Visuospatial neglect (VSN) is a neurological syndrome of higher brain functions in which an individual fails to detect stimuli on a space that is contralateral to a hemispheric lesion. We performed a comprehensive multivariate analysis based on the principal component analysis (PCA) and cluster analysis in patients with right hemisphere stroke and then performed a determination of different elements of VSN. PCA-based cluster analysis detected distinct aspects of VSN as follows: cluster 1: low arousal and attention state, cluster 2: exogenous neglect, cluster 3: spatial working memory (SWM) deficit. Lesion analysis revealed neural correlates for each cluster and highlighted "disturbance of the ventral attention network" for the stagnation of exogenous attention and "parietal damage" for SWM deficit. Our results reveal a pathological structure of VSN as multiple components of an attention network deficit, and they contribute to the understanding of the mechanisms underlying VSN.

Interaction between spatial neglect and attention deficit in patients with right hemisphere damage.

Unilateral spatial neglect (USN) was originally regarded as a parietal syndrome, but it has become evident that USN is a disturbance in the widespread attention network. Here, we focused on an interaction between spatial neglect and non-spatial aspect of attention deficit, and aimed to establish a novel evaluation approach based on the characteristics of the spatial distribution of reaction times. We tested 174 patients with right hemisphere damage and divided them based on their prescreening scores on the Behavioral Inattention Test (BIT): (1) USN++ (n = 79: BIT<131), (2) USN+ (n = 47: BIT≥131 with history of USN), and (3) RHD (n = 48: without neglect symptom). The patients were asked to conduct a touch panel-based pointing task toward 2D-arranged (seven columns × five rows) circular targets on a PC monitor, and the reaction time to each object was recorded. To evaluate aspects of attention deficit and neglect symptoms, we calculated the total average of the reaction time for all objects (RTmean) and the ratios of the right and left space (L/Rratio), respectively. The results revealed that RTmean and L/Rratio can be regarded as independent evaluation parameters for attention deficit and neglect symptoms, respectively. Voxel-based lesion-symptom mapping based on RTmean and L/Rratio values revealed relevant lesions with attention-related brain areas (middle temporal gyrus, angular gyrus, and inferior frontal gyrus), and neglect-related brain areas (superior temporal gyrus and superior longitudinal fascicules). A cluster analysis with Gaussian mixture model detected six different states of USN with an interaction between neglect symptoms and attention deficit. Interestingly, the recovery process after USN can be properly explained by the transition pattern from one cluster to another. Our results suggest that a novel evaluation approach to distinguish between neglect symptoms and attention deficit, namely the characterization of the interaction between RTmean and L/Rratio, provides useful information for understanding pathological features of USN.

Compact and Lightweight Transradial Electric Prosthesis for Children with Forearm Deficiency.

Children with congenital forearm deficiency have difficulty in daily activities and body balance problem. Since most electric prostheses have been developed for adult amputees, it is necessary to develop a compact and lightweight electric prosthesis for children to manipulate various daily objects. In this paper, we report a compact and lightweight transradial electric prosthesis for children with forearm deficiency. Based on an electric prosthesis termed as Finch for adult amputees, we designed a smaller electric prosthesis by using a compact actuator and a control unit. We downsized the fingers of the Finch without impairing the workability. The total weight of the developed prosthesis was 274 g, which was about 100 g lighter than that of the conventional electric prosthesis for children. The result of upper limb function evaluation using developed prosthesis participated in a child with congenital forearm deficiency demonstrated that the effectiveness of the prosthesis to manipulate daily objects.

Visual search pattern during free viewing of horizontally flipped images in patients with unilateral spatial neglect.

Eye tracking is an effective tool for identifying behavioural aspects of unilateral spatial neglect (USN), which is a common neurological syndrome that develops after a right hemisphere lesion. Here, we attempted to elucidate how the neglect symptom affects the symmetry of the gaze pattern, by performing an analysis of gaze distribution during the free viewing of a pair of horizontally flipped images. Based on their Behavioural Inattention Test (BIT) scores, 41 patients with right-hemisphere damage were classified into those with USN (n = 27) and those without USN (right hemisphere damaged - RHD; n = 14). Eye movement was recorded while the patients viewed six pairs of horizontally flipped images on a computer display. A pair of flipped images has both similar and consistent elements, as well as a reversed spatial location of objects (right-left). We calculated the gaze distribution, extent of gaze shift, total gaze distance, and gaze velocity in each direction. Our results demonstrated a significantly larger rightward gaze shift in the USN group, which showed a significant correlation with the BIT score. More importantly, the extent of gaze shift and total gaze distance were similarly modulated by the contents of the displayed images in both the USN and RHD groups. Our findings suggest that analyses of gaze distribution during the free viewing of a pair of horizontally flipped images have the potential to precisely reveal neglect behaviour, and our results provide important implications for rehabilitation.

Action observation facilitates motor cortical activity in patients with stroke and hemiplegia.

Motor imagery (MI) is a mental practice that reproduces the visual- and/or kinesthetic-modality brain activations accompanying movement. It is a useful rehabilitation technique as the affected motor cortex can be stimulated in patients with stroke and hemiplegia. However, most patients with stroke have difficulty with MI owing to advanced age and/or higher-cognitive dysfunction, thus impairing their ability to internally simulate the action. We therefore investigated whether action observation (AO), an alternative form of motor stimulation that works via the mirror-neuron system, could facilitate motor cortical activity in such patients. Combined AO and physical training of the observed actions has been reported to have a positive impact on motor deficits after stroke. Eleven patients with stroke and hemiplegia affecting the hand performed MI and AO with verbal and video instructions under 19 channels of electroencephalogram (EEG) recording. The event-related desynchronization (ERD) was measured as an electroencephalographic marker of motor cortical activity. The ERD power in the AO condition (30.0±5.0%) was significantly higher than that in the MI condition (12.2±3.9%). These results suggest that AO could be a good option for patients with stroke who have difficulty using MI to effectively stimulate and reestablish cortical-peripheral motor pathways.

Activation of the serotonergic system by pedaling exercise changes anterior cingulate cortex activity and improves negative emotion.

Pedaling exercise (PE) of moderate intensity has been shown to ease anxiety and discomfort; however, little is known of the changes that occur in brain activities and in the serotonergic (5-HT) system after PE. Therefore, this study was conducted for the following reasons: (1) to localize the changes in the brain activities induced by PE using a distributed source localization algorithm, (2) to examine the changes in frontal asymmetry, as used in the Davidson model, with electroencephalography (EEG) activity, and (3) to examine the effect of PE on the 5-HT system. A 32-channel EEG was used to record before and after PE. Profile of Mood States tests indicated that there was a significant decrease in tension-anxiety and a significant increase in vigor after PE. A standardized low-resolution brain electromagnetic tomography analysis showed a significant decrease in brain activities after PE in the alpha-2 band (10-12.5 Hz) in the anterior cingulate cortex (ACC). Moreover, a significant increase in frontal EEG asymmetry was observed after PE in the alpha-1 band (7.5-10 Hz). Urine 5-HT levels significantly increased after PE. Urine 5-HT levels positively correlated with the degree of frontal EEG asymmetry in the alpha-1 band and negatively correlated with brain activity in ACC. Our results suggested that PE activates the 5-HT system and consequently induces increases in frontal EEG asymmetry in the alpha-1 band and reductions of brain activity in the alpha-2 band in the ACC region.