Right-sided Brain Damage Research Articles

Zooming in on abnormal local and global processing biases after stroke: Frequency, lateralization, and associations with cognitive functions.

The 'attentional spotlight' can be adjusted depending on the task requirements, resulting in processing information at either the local or global level. Stroke can lead to local or global processing biases, or the inability to simultaneously attend both levels. In this study, we assessed the (1) prevalence of abnormal local and global biases following stroke, (2) differences between left- and right-sided brain damaged patients, and (3) relations between local and global interference, the ability to attend local and global levels simultaneously, and lateralized attention, search organization, search speed, visuo-construction, executive functioning, and verbal (working) memory. Stroke patients admitted for inpatient rehabilitation completed directed (N=192 total; N = 46 left-sided/N = 48 right-sided lesion) and divided (N = 258 total; N = 67 left-sided/N = 66 right-sided lesion) local-global processing tasks, as well as a conventional neuropsychological assessment. Processing biases and interference effects were separately computed for directed and divided tasks. On the local-global tasks, 7.8-10.9% of patients showed an abnormal local bias and 6.3-8.3% an abnormal global bias for directed attention, and 5.4-10.1% an abnormal local bias and 6.6-15.9% an abnormal global bias for divided attention. There was no significant difference between patients with left- and right-sided brain damage. There was a moderate positive relation between local interference and search speed, and a small positive relation between global interference and neglect. Abnormal local and global biases can occur after stroke and might relate to a range of cognitive functions. A specific bias might require a different approach in assessment, psycho-education, and treatment.

The amnestic syndrome of posterior cerebral artery infarction.

Background and purposeLittle is known about the character and underlying lesions of ischaemic amnesia. Episodic memory functions and brain lesions were therefore studied in 84 patients with acute ischaemic infarcts in the supply territory of the posterior cerebral artery. The aim was also to learn how the neural memory systems are organized.MethodsStandard neuropsychological tests were used to assess verbal and figural memory. Patients were split into memory‐impaired and memory‐intact groups. Lesions were demarcated, normalized and anatomically labelled, using standard mapping procedures.ResultsOf the 84 patients more than 80% had an amnestic syndrome, mostly with combined memory impairment, less often with figural or verbal memory impairment. Amnesia in subjects with left hemispheric lesions was more frequent and more severe, with significantly lower scores on the verbal memory test. Normal performance or figural amnesia were prevalent after right hemispheric lesions. However, no amnesia subtype was strictly tied to left‐ or right‐sided brain damage. Hippocampal and thalamic lesions were common, but 30% of lesions were extrahippocampal located in the ventral occipito‐temporal cortex and long occipital white matter tracts. Most amnestic patients lacked awareness for their memory impairment.ConclusionsMemory impairment is a key clinical manifestation of acute posterior cerebral artery stroke. Amnesia is more frequent and more severe after left stroke, suggesting a left hemisphere dominance of the two memory systems. Domain specific memory appears not to be strictly lateralized, since deficits in verbal and figural memory were found after lesions of both sides. Extrahippocampal lesions may also cause memory impairment.

Speech and Language Dysfunctions in Patients with Cerebrocortical Disorders Admitted in a Neurosurgical Unit.

Introduction:Speech and language abnormality among brain injury patients are common, especially during the acute stage. The details of same from Andhra Pradesh (AP) state are limited. The present study provides details of speech and language abnormality among brain damage patients, from a tertiary care hospital AP.Materials and Methods:This study was conducted at tertiary care hospital, Nellore, AP. Patients with acute brain damage due to traumatic brain injury (TBI), cerebrovascular accident (CVA), and postoperative cases of brain tumors were selected for the study. Detail of speech and language disturbances was accessed using Western Aphasia Battery. All patients were right-handed and Telugu was their first language.Results:There were totally 38 patients, of them 28 had TBI, 8 patients were postoperative cases of brain tumor, and 2 cases were of CVA. The mean age was 45.6 years. A total of 22 patients were literate. TBI patients with left cerebral hemisphere damage manifested with anomic, conduction, transcortical sensory, global, and Wernicke's aphasia. Four patients of postoperative brain tumor manifested with anomic and transcortical sensory aphasia had left-sided brain damage and mild dysarthria had right-sided brain damage patient. CVA patients had anomic aphasia and subcortical aphasia having right and left cerebral hemisphere damage, respectively.Conclusions:This study reports that acute brain damage due to various causes manifest with speech and language abnormality, especially when the left cerebral hemisphere is involved.

Connection Disruption Underlying Attention Deficit in Subcortical Stroke.

Purpose To investigate neural substrates underlying attention deficit in patients with chronic subcortical stroke by combining voxel-based lesion-symptom mapping (VLSM) and diffusion-tensor (DT) tractography. Materials and Methods Institutional review board approval and written informed consent were obtained. Diffusion magnetic resonance imaging data were prospectively acquired from August 1, 2014, to March 30, 2015, in 49 patients (32 men, 17 women; mean age, 55.7 years ± 8.0; age range, 40-71 years) with subcortical infarctions in the basal ganglia and neighboring regions and 52 control subjects (30 men, 22 women; mean age, 54.4 years ± 7.5; age range, 40-68 years). A modified version of the attention network test was used to assess visual attention function. On the basis of the lesion map at the acute stage, VLSM was used to identify lesion locations related to attention deficit in patients with stroke. DT tractography then was used to determine the responsible impaired connections by using diffusion data at the chronic stage (>6 months after stroke). Results When compared with control subjects, patients with chronic stroke exhibited prolonged reaction time (RT) of correct responses (P = .009). VLSM revealed that acute stroke lesion in the right caudate nucleus and nearby white matter (found in seven patients) was correlated with the prolonged RT (P < .05). DTT showed that the responsible lesion was located in the right thalamic- and caudate-prefrontal pathways in control subjects. The subgroup with right-sided brain damage had significantly decreased fractional anisotropy in these pathways (P < .001), which were correlated with the prolonged RT (P = .009 for the thalamic-prefrontal pathway, P < .001 for the caudate-prefrontal pathway). Conclusion Thalamic-prefrontal and caudate-prefrontal pathways impaired by stroke lesions appear to underlie attention deficit in patients with subcortical stroke in the right hemisphere.

Combining left neck muscle vibration to voluntary arm movements: To new perspectives in the therapeutic care in neglect

Among “Bottom-Up” treatments of unilateral spatial neglect (USN), left neck muscle vibration may reduce clinical symptoms in patients with right-sided brain damage. Shifting whole egocentric coordinate system, one of interests of this stimulation is that the patient is unaware of the perceptual and behavioral changes induced. Moreover, several studies have shown superior effects of combination treatments when their own effects were convergent. However, their practical applications are often conflicting with the constraints of patient care. This study aimed to assess the effects of a protocol of left neck muscle vibration during arm movements in the peri-personal space on the egocentric and allocentric perceptions of patients with left-sided spatial neglect (USNleft). Five USNleft patients (54.5 ± 5.5 years) were asked to perform the Marguerite test and a haptic straight-ahead test (20 ballistic pointings) without vision before protocol (Pre), immediately after (Post0), one hour later (Post1 h). During a therapeutic protocol of 15 minutes left trapezius muscle vibration (100 Hz–300 μm), they were asked to point to one of 5 lit targets [0° (straight ahead), 10° and 20° on the right and on the left], from the base of the chin rest with their right index finger, as quickly as possible. The results suggested a reduction of neglect symptoms for at least 1 hour after the protocol. The Marguerite test (Pre = 20.01 ± 8.21) showed an evolution by step of the laterality index with a dramatic decreasing at Post0 (−13.29), followed by a small reduction of this effect at Post1 h (−5.82). The errors during straight-ahead test (Pre = 12.66° ± 10) indicated a left lasting deviation after the protocol (stimulation effect at Post0 = −3.49°; Post1 h = −4.80°). Combining left neck vibration to arm movements has shown allocentric and egocentric improvements lasting for at least 1 hour, and our data in progress even suggest during 24 hours. Non-invasive and simple to use, these promising findings for the rehabilitation of spatial cognition disorders argue in favor of the ecological use of the vibratory tool during the rehabilitation sessions.

Sex-related functional asymmetry of the ventromedial prefrontal cortex in regard to decision-making under risk and ambiguity

Previous work has provided preliminary indication of sex-related functional asymmetry of the ventromedial prefrontal cortex (vmPFC) in social and emotional functions and complex decision-making. Findings have been inconsistent, and based on small numbers of patients. Given the rarity of these neurological cases, replicable results across studies are important to build evidence for sex-related functional asymmetry of the vmPFC. Here we used a sample of sixteen neurological patients with unilateral damage to the left or right vmPFC and examined differences between men and women on a task that probed decision-making under risk or decision-making under ambiguity. We found that men with right-hemisphere vmPFC damage and women with left-hemisphere vmPFC damage demonstrated significantly reduced aversion to risk and ambiguity. Men with damage to the left vmPFC and women with damage to the right vmPFC showed aversion to risk and ambiguity comparable to participants with left or right-sided brain damage outside the vmPFC, and to comparison participants without brain damage. Our results add to previous findings of sex-related functional asymmetry of the vmPFC in decision-making. Our study also replicates findings of no observable behavioral differences between men and women without neurological damage on tests of decision-making. This pattern of neurobiological divergence but behavioral convergence between men and women may reflect a complex interplay of neuroendocrine, developmental, and psychosocial factors.

Visual context modulates the subjective vertical in neglect: evidence for an increased rod-and-frame-effect

Patients with spatial hemi-neglect display systematic deviations of the subjective vertical. The magnitude of such deviations was shown to be modulated by internal factors mediating the perception of verticality, including head-orientation. The present study investigated whether and how spatial orientation deficits are modulated by external, contextual changes in neglect patients. In a classic rod-and-frame task, we analyzed effects of frame orientation on the subjective visual vertical (SVV) in neglect patients, control patients with left- or right-sided brain damage without neglect and healthy participants. We found that neglect patients, but not brain-damaged control patients, generally display a systematic counterclockwise (CCW) tilt in their SVV judgments. Furthermore, all participant groups displayed a typical rod-and-frame effect (RFE), that is, a modulation of the SVV as a function of frame tilt. However, in the control groups, this modulation was only moderate whereas in the neglect group SVV judgments were substantially and systematically modulated by frame orientation: with CCW frame tilts, the spatial bias of neglect patients increased as a function of the magnitude of the tilt whereas with clockwise (CW) frame tilts, the spatial bias was decreased in case of moderate frame tilts and even reversed in case of stronger frame tilts, resulting in a substantial CW spatial bias. This dramatically enhanced RFE might be caused by a pathologically increased influence of contextual cues on the subjective vertical in neglect patients as a consequence of impaired processing of gravitational information. The results indicate a systematic bias of the subjective vertical along with an impairment of spatial orientation constancy which leads to severe perturbations of subjective space as well as an increased reliance on internal and external cues mediating the perception of verticality in neglect.

Effects of lateral head inclination on multimodal spatial orientation judgments in neglect: Evidence for impaired spatial orientation constancy

Recent research revealed that patients with spatial hemineglect show deficits in the judgment of the subjective vertical and horizontal. Systematic deviations in the subjective axes have been demonstrated in the visual and tactile modality, indicating a supramodal spatial orientation deficit. Further, the magnitude of the bias was shown to be modulated by head- and body-position. The present study investigated the effect of passive lateral head inclination on the subjective visual and tactile vertical and horizontal in neglect patients, control patients with left- or right-sided brain damage without neglect and healthy controls. Subjects performed visual- and tactile-spatial judgments of axis orientations in an upright head orientation and with lateral head inclination 25° in clockwise (CW) or counterclockwise (CCW) direction. Neglect patients displayed a marked variability as well as a systematic tilt in their spatial judgments. In line with a multisensory spatial orientation deficit their subjective vertical and horizontal was tilted CCW in the visual and in the tactile modality, while such a tilt was not evident in any other subject group. Furthermore, lateral head inclination had a differential effect in neglect patients, but not in control subjects. Neglect patients’ judgments were modulated in the direction of the head tilt (‘A-effect’). That is, a CCW inclination further increased the CCW spatial bias whereas a CW inclination decreased the spatial bias and thus led to approximately normal performance. The increased A-effect might be caused by a pathologically strong attraction of the subjective vertical by an idiotropic vector relying on the actual head orientation, as a consequence of impaired processing of gravitational information in neglect patients.

Evaluation of a test battery for hemineglect in elderly stroke patients for use by therapists in clinical practice

Hemineglect is not a single entity, and the syndrome has a number of sensory and motor manifestations. The purpose of this study was a) to measure performance of healthy elderly subjects on a battery of validated tests for hemineglect in order to establish appropriate cut-off scores and b) to assess performance of a large sample of elderly stroke patients in a rehabilitation unit, using the same battery. Tests were selected to identify rate of occurrence of hemineglect in visuo-spatial, representational, pre-motor and personal modalities. The battery was administered to 107 patients with right or left sided brain damage and 43 age-matched controls. Results showed that 39.2% right-sided brain damage), were 'neglecters', scoring below cut-off in one or more tests. Star Cancellation and Line Bisection showed the highest relative sensitivity for visuo-spatial neglect (76.4%) 'Baking Tray Task', the 'Exploratory Motor Task', and utilisation of common objects test for personal neglect are additionally suggested for use in the clinical situation. 'Copying a Daisy' and clock-drawing are not recommended due to low sensitivity and subjectivity in scoring respectively.

Unilateral Neglect: Mechanisms and Nursing Care

Unilateral neglect is frequently observed in brain-damaged persons, most commonly in conjunction with right-sided brain damage. Manifest as failure to attend to one-half of the body or extrapersonal space, unilateral neglect is caused by an attentional arousal deficit. Patients with unilateral neglect may present with a variety of behaviors. An understanding of causal mechanisms facilitates implementation of appropriate interventions to assist the patient and caregivers to cope with neglect and improve ability to perform activities of daily living.

The behavioural assessment of visual neglect

Abstract Unilateral visual neglect is among the most striking consequences of right-sided brain damage and is characterised by the patient's failure to respond to stimuli on the side contralateral to the lesion. Visual neglect disrupts many aspects of daily living such as mobility, dressing, and reading, yet the underlying mechanisms remain poorly understood. This paper describes the development, standardisation and validation of a test battery designed to identify a wide variety of visual neglect behaviours observed in clinical practice. The Behavioural Inattention Test (B.I.T.), which was standardised on a large stroke population (n = 80), is described. Unlike existing studies of visual neglect, the B.I.T. relates test results to functional assessment and rehabilitation. Using the test battery and normative data from 50 age-matched controls, 30 patients (37.5%) were classified as demonstrating neglect. Neglect is more frequent and severe following right-rather than left-sided lesions. Inter-rater, test-...

Tactile exploration of space and visual neglect in brain-damaged patients.

A maze test of tactile scanning was used to investigate the relationship between visual neglect and the tactile modality of space exploration in 46 patients with right-sided brain damage (RBD) (20 with and 26 without visual neglect), 27 patients with left-sided brain damage (LBD) and 30 controls. Both LBD and RBD patients that were free from visual neglect more frequently used the tactile mode to explore the space contralateral to the sound hemisphere, while the RBD patients affected by visual hemi-inattention preferred tactile scanning of the left, visually neglected, half of space. Some implications of these findings are discussed. In particular, the modality-specific nature of neglect phenomena and the possibility of tactile compensation are suggested.

Poor memory: a case report.

The patient and the author of this case report are the same person. In September 1974 I had a cardiac arrest, and because of anoxia, the arrest resulted in some right-sided brain damage. The brain damage led to some minor physical and perceptual problems, but the most important result was partial loss of past memory and strongly impaired present memory. This report will be concerned with the effects of poor memory on cognition, personality, and interpersonal relationships based on the observations I have made during the period in which my memory was impaired. Of course, the emotional and personality reactions are somewhat related to my past personality, but some may be expected generally when poor memory is present. The effect on cognitive functioning is more likely to be a general finding. I also will describe the course of my rehabilitation over a 2-year-period, and I will make some suggestions about rehabilitation to patients and therapists.

Conjugate gaze paresis in stroke patients with unilateral damage. An unexpected instance of hemispheric asymmetry.

Conjugate gaze paresis was investigated in 436 patients who had suffered a severe stroke and were consecutively hospitalized for unilateral hemispheric damage. Gaze paresis was found in 120 and was associated with a high mortality, severe neurological impairment, and was more frequent in women. However, conjugate gaze paresis was also dependent on the side and locus of the lesion. It was more frequent, severe, and long-lasting in patients with right-sided brain damage. Moreover, it was preponderantly associated with post-Rolandic lesions in patients with right-sided brain damage and with involvement of the entire territory of distribution of the Sylvian artery in those with left-sided brain damage. This suggests that oculomotor centers have an asymmetrical organization in the two hemispheres, diffuse on the left and focalized on the right. It also explains why visual neglect occurs more frequently following right-sided brain damage.

Ideatory Apraxia in a Left-Handed Patient with Right-Sided Brain Lesion

A case is described of a left-handed patient with a circumscribed right-sided posterior brain lesion, who presented with a neuro-psychological syndrome of Wernicke's aphasia, ideomotor and ideatory apraxia. The aphasia and ideomotor apraxia cleared within 10 days, while ideatory apraxia persisted. Ideatory apraxia therefore was not dependent on the language disorder, nor was it related to ideomotor apraxia. On the basis of various neuropsychological examinations, the nature of the apraxic movement disorder in this case is discussed. To our knowledge, this is the first case of ideatory apraxia with right-sided brain damage described in the literature. A particular feature of this patient is that obviously language and the motor functions underlying performance in tests for ideomotor apraxia had a bilateral hemispheric representation whereas a unilateral lesion was sufficient to bring about persistent ideatory apraxia.