Left Hemisphere Damaged Patients Research Articles

Temporal judgments of actions following unilateral brain damage

Sense of time is a complex construct, and its neural correlates remain to date in most part unknown. To complicate the frame, physical attributes of the stimulus, such as its intensity or movement, influence temporal perception. Although previous studies have shown that time perception can be compromised after a brain lesion, the evidence on the role of the left and right hemispheres are meager. In two experiments, the study explores the ability of temporal estimation of multi-second actions and non-biological movements in 33 patients suffering from unilateral brain lesion. Furthermore, the modulatory role of induced embodiment processes is investigated. The results reveal a joint contribution of the two hemispheres depending not only on different durations but also on the presence of actions. Indeed, the left hemisphere damaged patients find it difficult to estimate 4500 ms or longer durations, while the right hemisphere damaged patients fail in 3000 ms durations. Furthermore, the former fail when a biological action is shown, while the latter fail in non-biological movement. Embodiment processes have a modulatory effect only after right hemisphere lesions. Among neuropsychological variables, only spatial neglect influences estimation of non-biological movement.

Gesture errors in left and right hemisphere damaged patients: A behavioural and anatomical study

ObjectiveErroneous gesture execution is at the core of motor cognition difficulties in apraxia. While a taxonomy of errors may provide important information about the nature of the disorder, classifications are currently often inconsistent. This study aims to identify the error categories which distinguish apraxic from non-apraxic patients. Method. Two groups of mixed (bucco-facial and limb) and bucco-facial apraxic patients suffering from stroke were compared to non-apraxic, left and right hemisphere damaged patients in tasks tapping the ability to perform limb and bucco-facial actions. The errors were analysed and classified into 6 categories relating to content, configuration or movement, spatial or temporal parameters and unrecognisable actions. Furthermore, an anatomical investigation (VLMS) was conducted in the whole group of left hemisphere damaged patients to investigate potential correlates of the various error categories. Results. Although all the above error typologies may be observed, the most indicative of mixed apraxia is the content-related one in all the typologies of actions (transitive and intransitive), and configuration errors in transitive ones. Configuration and content errors in mouth actions seem to be typical of bucco-facial apraxia. Spatial errors are similar in both apraxic and right brain damaged, non-apraxic patients. A lesion mapping analysis of left-brain damaged patients demonstrates that all but the spatial error category are associated with the fronto-parietal network. Moreover, content errors are also associated with fronto-insular lesions and movement errors with damage to the paracentral territory (precentral and postcentral gyri). Spatial errors are often associated to ventral frontal lesions. Conclusions. Bucco-facial and mixed apraxic patients make different types of errors in different types of actions. Not all errors are equally indicative of apraxia. In addition, the various error categories are associated with at least partially different neural correlates.

Comparative Analysis of Facial Expressions of Right and Left Hemisphere Damaged Patients Using Facial Action Coding System

Comparative Analysis of Facial Expressions of Right and Left Hemisphere Damaged Patients Using Facial Action Coding System

Setting the midpoint of sentences: The role of the left hemisphere

The human brain has a remarkable capacity to focus processing resources based on the features and the relevance of the task at hand. The two cerebral hemispheres contribute differentially to this capacity, with the left hemisphere linguistic and right hemisphere visuo-spatial abilities each offering unique contributions. For example, previous research has established that healthy participants set the subjective mid-point of written sentences more leftwards of center, compared to unpronounceable letter strings or simple lines. Remarkably, patients with right hemisphere damage exhibiting unilateral spatial neglect also show this pattern, even though, as well known in the literature, they tend toward a rightward- bias for non-linguistic stimuli. This evidence suggests that the leftward bias for sentential material is due to linguistic, mainly left-hemisphere mediated processes, which are largely unimpaired in right brain-damaged patients, and intact in heathy participants. To test this hypothesis, we compared sentence bisection performance to that of letter strings and simple lines in left brain-damaged patients (with and without aphasia). If the larger leftward bias in the bisection of sentential material is based on linguistic processes, then the left brain-damaged patients should show a reduction or absence of a leftward bias in sentence bisection. We tested twenty-four left brain-damaged patients (12 with aphasia and 12 without aphasia), and 24 age-matched elderly participants (patients and controls were all right-handed). Participants were asked to bisect 240 stimuli, comprising: (i) affirmative and interrogative clauses, (ii) sentences with lexical and syntactic violations, (iii) letter strings and (iv) simple lines. As predicted, neurologically intact participants showed larger leftward biases in bisecting written readable sentences compared to strings of letters. In contrast, the left hemispheredamaged patients (both with and without aphasia) showed no differences in bisecting sentences and letter strings or lines. These findings indicate that the larger leftward bias exhibited by healthy participants in the bisection of sentences is likely due to ortho-phonological coding taking place implicitly during the bisection task. This ortho-phonological coding is impaired with left brain damage – also in absence of apparent aphasia – leading to the left hemispheredamaged patients showing a reduced leftward bias in sentence bisection. These findings support the hypothesis that the leftward bias in the bisection of written sentences is the result of ortho-phonological influences rather than visual-spatial biases.

Spatial asymmetries undermine also the short forms of the Judgement of Line Orientation test.

The Judgment of Line Orientation (JLO) test is one of the most used tasks for the assessment of visuospatial perception. However, JLO items show a left-right structural asymmetry that interacts with the ipsilesional attentional biases of brain-damaged patients, that is, the main target population for which the test is intended, and undermines the test's validity. Left hemisphere-damaged patients are favored by the way the stimulus lines are distributed in the original items, whereas right hemisphere-damaged patients are favored by the opposite distribution, obtained by mirror reversing the items (Treccani, Torri, & Cubelli, 2005). Here we aimed to analyze the short forms of JLO available in the literature, which are often presented as preferable alternatives to the full form. Characteristics of the items of these short forms were scrutinized. By reanalyzing data from Treccani et al. (2005), we also investigated the impact of these characteristics on brain-damaged patients' performance. Seven of the 8 analyzed short forms proved to be even more asymmetric than the full form (e.g., they have a different number of left and right lines), whereas the remaining one, which uses a flexible item-selection criterion, leads to unpredictable results. Like in the full form, these asymmetries affect brain-damaged patients' performance. The presence of spatial asymmetries in JLO items cannot be neglected anymore in the development of any JLO form, given their impact on performance and the resulting detrimental effect on the accuracy and validity of the measurement. We propose to select 5-10 items among those of the original set and present them together with their mirror images to obtain a left-right balanced JLO short version. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Effects of lesion extent and location on upper limb function following hemispheric stroke

A large proportion of stroke survivors present spastic paresis of the upper limb (UL). Therapeutic interventions result in large variance in the response of patients to the same treatment protocols, possibly stemming from differences in lesion characteristics, among other factors. Here we concentrated on the impact of lesion size and location on UL function following stroke, comparing the effect of right hemisphere damage (RHD) to that of left hemisphere damage (LHD). Clinical and lesion data for the current study were collected as part of a multicenter randomized, controlled trial (ENHANCE project; ClinicalTrials.gov, ID: NCT02725853 ). Two groups of patients with subacute stroke were compared: those with right hemisphere ( n = 8) and left hemisphere damage ( n = 15). Voxel-based lesion symptom mapping (VLSM) was employed to identify voxel clusters in the normalized brain where damage exerts a significant impact on the functioning of the hemiparetic UL, as revealed by the Functional Ability Scale of the short (streamlined) version of the Wolf Motor Function Test. Motor function of the hemiparetic UL was affected in LHD patients by damage to voxel clusters involving (a) cortical areas of the superior temporal regions and the insula, (b) white matter tracts, notably the superior and inferior fronto-occipital fascicles, the corona radiata and the internal capsule, and (c) the basal ganglia and thalamus. In the RHD group, VLSM analysis showed a different pattern where UL function was affected almost exclusively by damage to subcortical structures of the corona radiata, the capsular-putaminal region, the superior longitudinal fasciculus and the external capsule. Motor function of the hemiparetic upper limb in patients with subacute stroke was affected differently by damage to homologous structures in the left and right cerebral hemispheres.

The Study Trends of the Right Hemisphere Damage Cognitive-Communication Disorders - Focused of Recent 10 Years -

우반구 손상(Right Hemisphere Damage, RHD)에 따른 의사소통장애는 좌반구 손상 환자군과는 다른 양상을 보이며, 좌반구 손상 환자 대상의 실어증 평가에서는 그 장애 정도가 잘 감별되지 않기 때문에 이들에 대한 언어 평가와 중재연구가 적극적으로 이루어지지 않고 있다. 본 연구에서는 최근 10년간 국내외 관련 학술지에서 다루어진 RHD 환자에 대한 연구논문을 분석하여 RHD 환자의 의사소통장애 평가와 중재 방향에 대한 동향을 파악하고, 향후 임상과 연구 영역에서의 시사점을 얻고자 하였다. 국내외 논문 총 75편(국내 논문 13편, 국외 논문 62편)을 대상으로 연구유형과 연구영역으로 나누어 분석을 실시하였다. 연구유형 및 연구영역에서 국내외 동일하게 RHD 환자의 인지-의사소통장애 특성을 비교하고, 언어외적 능력을 가장 많이 살펴본 것으로 나타났다. 그러나 평가도구 개발 연구 및 인지-의사소통 외 능력(예: 일상생활능력, 우울)과 같이 다양한 주제에 대한 연구가 빈번히 이루어져 있는 국외 연구와는 달리 국내 연구는 아직까지 제한적인 범위 내에서만 이루어져 있었다. 본 논문을 통해 파악된 RHD 환자군의 국내외 연구 동향을 통해 향후 국내 RHD 환자를 대상으로 한 임상장면과 연구에서 다양하고 심도 높은 연구가 이루어질 것으로 기대한다.Communication disorders caused by Right Hemisphere Damage manifests different symptom with that of left, and studies concerning language evaluation and intervention have not been actively investigated because they are either mild or difficult to discern through the aphasic assessment targeted to left hemisphere damage patients. This study analyzes domestic and international RHD group study trends in last 10 years for the purpose of examining the trends regarding directions of RHD group communication disorders and intervention. 75 thesis were analyzed(13 domestic and 62 international) after classifying them into two categories, study type and research area. Regarding research type, both domestic and international studies primarily comprised characteristic comparison. As for the research area, both studies mainly investigated on extra-linguistic ability. While international studies frequently investigated the development and suitability of evaluation instrument as well as RHD group s activities of daily life. Domestic studies have shown limited scopes of research. Therefore, it seems that more attention should henceforth be payed to RHD patients in domestic level, and in-depth studies of diverse subjects should be conducted as well.

Left inferior frontal gyrus mediates morphosyntax: ERP evidence from verb processing in left-hemisphere damaged patients

Neurocognitive models of language comprehension have proposed different mechanisms with different neural substrates mediating human language processing. Whether the left inferior frontal gyrus (LIFG) is engaged in morpho-syntactic information processing is currently still controversially debated. The present study addresses this issue by examining the processing of irregular verb inflection in real words (e.g., swim > swum > swam) and pseudowords (e.g., frim > frum > fram) by using event-related brain potentials (ERPs) in neurological patients with lesions in the LIFG involving Broca's area as well as healthy controls. Different ERP patterns in response to the grammatical violations were observed in both groups. Controls showed a biphasic negativity-P600 pattern in response to incorrect verb inflections whereas patients with LIFG lesions displayed a N400. For incorrect pseudoword inflections, a late positivity was found in controls, while no ERP effects were obtained in patients. These findings of different ERP patterns in the two groups strongly indicate an involvement of LIFG in morphosyntactic processing, thereby suggesting brain regions' specialization for different language functions.

Multi-tasking uncovers right spatial neglect and extinction in chronic left-hemisphere stroke patients

Unilateral Spatial Neglect, the most dramatic manifestation of contralesional space unawareness, is a highly heterogeneous syndrome. The presence of neglect is related to core spatially lateralized deficits, but its severity is also modulated by several domain-general factors (such as alertness or sustained attention) and by task demands. We previously showed that a computer-based dual-task paradigm exploiting both lateralized and non-lateralized factors (i.e., attentional load/multitasking) better captures this complex scenario and exacerbates deficits for the contralesional space after right hemisphere damage. Here we asked whether multitasking would reveal contralesional spatial disorders in chronic left-hemisphere damaged (LHD) stroke patients, a population in which impaired spatial processing is thought to be uncommon. Ten consecutive LHD patients with no signs of right-sided neglect at standard neuropsychological testing performed a computerized spatial monitoring task with and without concurrent secondary tasks (i.e., multitasking). Severe contralesional (right) space unawareness emerged in most patients under attentional load in both the visual and auditory modalities. Multitasking affected the detection of contralesional stimuli both when presented concurrently with an ipsilesional one (i.e., extinction for bilateral targets) and when presented in isolation (i.e., left neglect for right-sided targets). No spatial bias emerged in a control group of healthy elderly participants, who performed at ceiling, as well as in a second control group composed of patients with Mild Cognitive Impairment. We conclude that the pathological spatial asymmetry in LHD patients cannot be attributed to a global reduction of cognitive resources but it is the consequence of unilateral brain damage. Clinical and theoretical implications of the load-dependent lack of awareness for contralesional hemispace following LHD are discussed.

Predictability effect reflects different contributions from each hemisphere: data from left and right hemisphere damage patients

Predictability effect reflects different contributions from each hemisphere: data from left and right hemisphere damage patients

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.

Prosody Processing of Korean Language in Stroke Patients: A Preliminary Study

ObjectiveTo investigate the hemispheric contributions to prosody recognitions and interference effects of semantic processing on prosody for stroke patients by using the Korean language.MethodsTen right hemisphere damaged patients (RHD), nine left hemisphere damaged patients (LHD), and eleven healthy controls (HC) participated. In pure prosody recognition task, four semantically neutral sentences were selected and presented in both sad and happy prosodies. In interference task, participants listened to emotionally intoned sentences in which the semantic contents were congruent or incongruent with prosody. Participants were asked to rate the valence of prosody while ignoring the semantic contents, and thus, reaction time and accuracy were estimated.ResultsIn pure prosody recognition task, RHD showed low accuracy as compared to HC (p=0.013), and the tendency of group response showed that RHD performed worse than HC and LHD with regards to accuracy and reaction time. In interference task, analysis of accuracy revealed a significant main effect of groups (p=0.04), and the tendency implied that RHD is less accurate as compared to LHD and HC. The RHD took longer reaction times than HC in congruent and incongruent items (p<0.001).ConclusionRight hemispheric laterality to prosody processing of Korean language in stroke patients was observed. Interference effects of semantic contents to prosody processing were not observed, which suggested unique characteristics of prosody for Korean language. These results could be referred as preliminary data for future researches on Korean languages.

Prevalence and Length of Recovery of Pusher Syndrome Based on Cerebral Hemispheric Lesion Side in Patients With Acute Stroke

The aim of this study was to determine if side of cerebral hemisphere lesion affects the prevalence and time course of pushing behavior (PB) after stroke. A total of 1660 patients with acute stroke were investigated. PB was assessed using the standardized Scale for Contraversive Pushing. Risk ratios were used to evaluate the differences in the prevalence of PB between right cerebral hemisphere-damaged (RCD) and left cerebral hemisphere-damaged (LCD) patients. The differences in the time course among 35 (27 RCD and 8 LCD) patients were evaluated by analyzing Scale for Contraversive Pushing scores with the Kaplan-Meier method using a log-rank test. PB was observed in 156 (9.4%) patients. The prevalence of PB was significantly higher in RCD (97 of 556 [17.4%]) than in LCD (57 of 599 [9.5%]) patients; risk ratio was 1.83 (95% CI, 1.35-2.49). The log-rank test indicated that RCD patients exhibited a significantly slower recovery than LCD patients (P=0.027). The number of RCD patients who exhibited PB was higher than that of LCD patients. The duration of recovery from PB was longer in RCD patients than in LCD patients.

Functional Organization of the Neural Language System: Dorsal and Ventral Pathways Are Critical for Syntax

The core of human language, which differentiates it from the communicative abilities of other species, is the set of combinatorial operations called syntax. For over a century researchers have attempted to understand how this essential function is organized in the brain. Here, we combine behavioral and neuroimaging methods, with left hemisphere-damaged patients and healthy controls, to identify the pathways connecting the brain regions involved in syntactic processing. In a previous functional magnetic resonance imaging study (Tyler LK, Wright P, Randall B, Marslen-Wilson WD, Stamatakis EA. 2010b. Reorganization of syntactic processing following left-hemisphere brain damage: does right-hemisphere activity preserve function? Brain. 133(11):3396-3408.), we established that regions of left inferior frontal cortex and left posterior middle temporal cortex were activated during syntactic processing. These clusters were used here as seeds for probabilistic tractography analyses in patients and controls, allowing us to delineate, and measure the integrity of, the white matter tracts connecting the frontal and temporal regions active for syntax. We found that structural disconnection in either of 2 fiber bundles--the arcuate fasciculus or the extreme capsule fiber system--was associated with syntactic impairment in patients. The results demonstrate the causal role in syntactic analysis of these 2 major left hemisphere fiber bundles--challenging existing views about their role in language functions and providing a new basis for future research in this key area of human cognition.

Lexical tone disruption in Shona after brain damage

Background: The issue of production and perception of lexical tone in patients with brain lesions has been investigated mainly through East Asian languages and Norwegian. The present study investigated the lateralisation of lexical tone in Shona, a Bantu language. Van Lancker (1980) proposed a continuum scale of the levels of functional pitch in the speech signal. According to the functional lateralisation account (FLH), the left hemisphere (LH) is associated with highly structured pitch contrasts, such as phonological tone, whereas the right hemisphere (RH) is specialised for the least structured pitch functions cueing emotional and personal information. The extant data show that the ability to produce and identify lexical tone is frequently more impaired as a result of lesions to the LH than RH lesions. Aims: The present investigation focused on the lateralisation of lexical tone in Shona speakers. The study sought to validate if the scale of hemispheric lateralisation as proposed by Van Lancker (1980) is also valid for Shona, a Bantu language. Methods & Procedures: We examined five LH damaged (LHD) patients and five RH (RHD) damaged patients using a confrontational picture-naming task and a lexical tone identification task of Shona lexical tone. The first experiment investigated the ability of LHD patients and RHD patients to identify Shona lexical tone in 60 disyllabic minimal pairs. The second experiment examined the ability of Shona brain-damaged patients to produce lexical tone using a confrontational picture-naming task with 120 lexical items. Outcomes & Results: We observed a dissociation in the performance of both the LHD and RHD patients in the two tasks. Both groups were impaired in the tone identification task relative to the non-brain-damaged controls. However, RHD patients performed significantly better than the LHD patients in the tone identification task. On the other hand, both LHD and RHD groups were equally impaired in the tone production task in comparison to the controls. Conclusions: The discrepancy in the production and perception of Shona lexical tone for this group of brain-damaged patients shows that, although the two modes are related, they do not always get disrupted at the same level after brain damage. The results from the tone identification task suggest to a certain extent that the FLH is also valid for Shona. In order to account for all the data there is need to carefully consider alternative accounts like the acoustic cue hypothesis (Van Lancker & Sidtis, 1992).

The nature of hemispheric specialization for linguistic and emotional prosodic perception: A meta-analysis of the lesion literature

It is unclear whether there is hemispheric specialization for prosodic perception and, if so, what the nature of this hemispheric asymmetry is. Using the lesion-approach, many studies have attempted to test whether there is hemispheric specialization for emotional and linguistic prosodic perception by examining the impact of left vs. right hemispheric damage on prosodic perception task performance. However, so far no consensus has been reached. In an attempt to find a consistent pattern of lateralization for prosodic perception, a meta-analysis was performed on 38 lesion studies (including 450 left hemisphere damaged patients, 534 right hemisphere damaged patients and 491 controls) of prosodic perception. It was found that both left and right hemispheric damage compromise emotional and linguistic prosodic perception task performance. Furthermore, right hemispheric damage degraded emotional prosodic perception more than left hemispheric damage (trimmed g=−0.37, 95% CI [−0.66; −0.09], N=620 patients). It is concluded that prosodic perception is under bihemispheric control with relative specialization of the right hemisphere for emotional prosodic perception.

Overestimation of Self-reported Activities of Daily Living in Vascular Dementia Patients with a Right Hemisphere Lesion

Several studies have analyzed the perception of activities of daily living (ADL) in stroke patients based on the discrepancy between scores given by the patients and their caregivers, and the results have been controversial. The aim was to evaluate the discrepancy between self-rating of ADL in vascular dementia (VaD) patients and evaluation by caregivers. We hypothesized that patients with right hemisphere damage (RHD) would overrate themselves on the Barthel Index (BI) compared to those with left hemisphere damage (LHD). Sixty VaD patients, including 30 each with damage to the left and right hemispheres, were studied. The BI was used to evaluate ADL. The self-rating BI score was based on an interview of the subjects. The difference between these score was used as a measure of overrating. The mean BI score for LHD patients was higher than that for RHD patients. Although there was no significant difference in the self-rated BI scores between the 2 groups, the difference between self-rated BI and BI was significantly larger in RHD patients: 6 patients had damage to the right insular cortex. Additional analysis for 7 RHD and 7 LHD patients by matching the BI and Mini-Mental State Examination scores disclosed that the difference remained larger in the RHD patients. RHD patients had a higher self-rating for their ADL scores compared to the rating given by caregivers. It is possible that the patients overrated their capability because they were unable to imagine risks such as a fall because of right insular damage.

Is left fronto-temporal connectivity essential for syntax? Effective connectivity, tractography and performance in left-hemisphere damaged patients

Syntactic processing typically engages left inferior frontal gyrus and posterior middle temporal gyrus, and damage to these regions is associated with syntactic deficits. What has not been directly determined, however, is whether it is the effective connectivity between these regions - and therefore also the integrity of the white matter tracts that connect them - that underpins successful syntactic analysis. We addressed these related issues by obtaining measures of the psycho-physiological interaction between frontal and temporal regions and of the integrity of the major white matter tracts that directly connect them - the arcuate fasciculus and extreme capsule fibre system. We correlated these estimates with performance measures of syntax in a group of patients with left hemisphere damage and varying degrees of syntactic impairment. Good syntactic function was associated with enhanced effective connectivity and increased tract integrity, suggesting that intact connectivity between left frontal and temporal regions is essential for syntactic analysis rather than the activation of these regions per se.

Perceptual discrimination of Shona lexical tones and low-pass filtered speech by left and right hemisphere damaged patients

Background: While the role of the right hemisphere (RH) in prosodic processing is prominent, research on the perception of lexical tones has shown that left hemisphere damaged (LHD) patients are more impaired than right hemisphere damaged (RHD) patients. Dichotic listening and imaging studies with healthy speakers of tone languages demonstrate that at least at the phonemic and lexical level, prosody is processed in the left hemisphere (LH) when the variations in pitch are phonemically distinctive. There is no report available yet on the perceptual discrimination of a Bantu language in patients after unilateral brain damage. Aims: We addressed the question of how well Shona aphasic patients and right hemisphere damaged patients perceive pitch contrasts in Shona lexical words and also in their homologous low-pass filtered counterparts. We also sought to discover the validity of the current hypotheses on hemispheric lateralisation particularly the hypothesis on hemispheric lateralisation based on language function to account for the Shona data. Methods & Procedures: A total of 7 LHD and 7 RHD patients and 14 healthy controls participated in two discrimination tasks that examined perception of lexical tone in (a) bisyllabic Shona words and (b) low-pass filtered stimuli. In both tasks the participants were tasked with judging the pitch as the same or different in 120 bisyllabic words and 120 low-pass filtered stimuli. Outcomes & Results: The results demonstrated that the tonal discrimination of the LHD group was more reduced in comparison to the RHD group and control participants. However, the performance of the RHD patients was not error free relative to the control participants, although significantly better than the LHD patients in both tasks. Conclusions: At least for the phonemic and lexical levels, brain damage to the dominant hemisphere results in lexical tone impairment for LHD patients, and cognitive load processing results in a subdued but good performance for RHD patients. The LH is therefore dominant for processing tone when it is lexically distinctive.

The need for a revised version of the Benton judgment of line orientation test

The Judgment of Line Orientation Test (JLOT) is considered a valid task for the assessment of visuospatial perception, and, for this reason, it is also considered to be a sensitive tool able to discriminate between right-hemisphere-damaged (RHD) patients and left-hemisphere-damaged (LHD) patients. In contrast with this view, we report evidence that the greater impairment in JLOT usually shown by RHD patients is unrelated to the supposed JLOT effectiveness in measuring visuospatial judgment ability and to the putative dominant role of the right hemisphere in visuospatial processing. JLOT is characterized by a left–right structural asymmetry (i.e., left-side lines are easier to judge) that seriously undermines the test validity: This asymmetry interacts with ipsilesional attentional biases of brain-damaged patients and affects their performance. Results obtained with a JLOT version composed of both the original items and their mirror-reversed versions clearly indicate that the cognitive functions tested by the JLOT are distributed across the two hemispheres: LHD and RHD patients did not differ from each other or from their matched controls when their performances were compared on this balanced JLOT version. Impaired performances of either RHD or LHD patients were found only when performances in original and mirror-reversed items were considered separately. This suggests that the original JLOT cannot assess visuospatial perception independently from attentional biases. The test can be a powerful clinical tool, as long as both original and mirror-reversed items are used, and the standard scoring method is replaced by the evaluation of the individual lines of stimulus pairs.