Response to Speech and Language Therapy According to Artery Involvement and Lesion Location in Post-stroke Aphasia.

PURPOSE: Aphasia is one of the most common complications after stroke and occurs in 21-38% of the patients during acute period. The present study aimed to investigate the response to speech and language therapy according to artery involvement and lesion location in patients with post-stroke aphasia. METHOD: The medical records of 107 patients with post-stroke aphasia (mean age, 58.8 ± 14.8 years) who were admitted to a single rehabilitation center for usual care after stroke were reviewed. Location of the ischemic lesion and involved artery was determined assessing the brain MRI of the patients. All the patients received 24 sessions speech and language therapy (3 days a week) as a part of 8-week rehabilitation program. Evaluation of the aphasia was performed with Gülhane Aphasia Test-2 (GAT-2) at baseline and at the end of the rehabilitation program. RESULTS: Baseline GAT-2 scores was significantly worse in patients with middle cerebral artery (MCA) involvement compared to patients with other artery involvements (p = 0.007). While the GAT-2 scores of patients with MCA involvement were improved significantly after speech and language therapy (p < 0.001), the changes in those with anterior cerebral artery (ACA) and posterior cerebral artery (PCA) involvements were not significant (p > 0.05). CONCLUSIONS: The present findings suggested that speech functions might be more affected in ischemic lesion of MCA and response to SLT might be better in patients with MCA involvement.

Differences in Ischemic Anterior and Posterior Circulation Strokes: A Clinico-Radiological and Outcome Analysis.

BACKGROUND: There are limited data comparing posterior (PC) and anterior (AC) circulation acute ischemic strokes (AIS). We aimed to identify specific features of PC and AC strokes regarding clinical, etiological, radiological, and outcome factors. METHODS: Patients from the Acute STroke Registry and Analysis of Lausanne, a prospective cohort of consecutive AIS, from years 2003 to 2008 were included. The stroke territory was determined by a combination of neuroimaging and clinical symptoms. Patients with uncertain localization or with simultaneous AC and PC strokes were excluded. Multivariate associations between territory and multiple variables were investigated. RESULTS: A total of 1449 patients were included, 466 (32.2%) had a PC territory stroke and 983 (67.8%) an AC. On multivariate analysis, those with PC AIS had lower National Institutes of Health Stroke Scale at admission, more often showed decreased consciousness, visual field defects, and vestibulo-cerebellar signs, but less hemisyndromes, dysarthria, and cognitive symptoms compared to AC AIS patients. Male sex, arterial dissection, lacunar mechanisms, and endovascular recanalization were more frequent in PC strokes, whereas cardioembolic strokes and IV-thrombolysis rates were lower. Less early ischemic signs on admission CT, overall arterial pathology, and 24-hour recanalization were present in PC strokes but intracranial arterial pathology was more prevalent than in AC. The adjusted clinical outcome at 3 months was similar in both groups. CONCLUSIONS: In this large retrospective consecutive AIS series, there were specific differences in clinical presentation, etiology, and arterial pathology between PC and AC strokes which did not influence clinical outcome. These findings could lead to a tailored diagnostic work-up, acute treatment strategies, and secondary prevention.

Transient Effects of Gaze Stability Exercises on Postural Stability in Patients With Posterior Circulation Stroke.

The authors sought to investigate if short-term gaze stability exercises have an effect on postural stability of dynamic standing during neck movement in patients with posterior circulation stroke (PCS). Patients in both PCS and non-PCS groups were assigned to either an intervention or control group. The intervention group performed the gaze stability exercises for 10 min while the control group was merely resting. The center of pressure velocity was calculated to evaluate the postural stability. After intervention, PCS and non-PCS showed a significant reduction in center of pressure velocity during dynamic standing with eyes closed condition, and the PCS group showed a significant improvement in eye-opened condition. This study indicated that gaze stability exercises improve PCS patients' postural control, especially during dynamic standing.

e-NIHSS: an Expanded National Institutes of Health Stroke Scale Weighted for Anterior and Posterior Circulation Strokes.

BACKGROUND: The National Institutes of Health Stroke Scale (NIHSS) is the most widespread clinical scale used in patients presenting with acute stroke. The merits of the NIHSS include simplicity, quickness, and agreement between clinicians. The clinical evaluation on posterior circulation stroke remains still a limit of NIHSS. METHODS: We assessed the application of a new version of NIHSS, the e-NIHSS (expanded NIHSS), adding specific elements in existing items to explore signs/symptoms of a posterior circulation stroke. A total of 22 consecutive patients with suspected vertebrobasilar stroke were compared with 25 patients with anterior circulation stroke using NIHSS and e-NIHSS. RESULTS: We compared the NIHSS and e-NIHSS scores obtained by the 2 examiners, in patients with posterior circulation infarct (POCI), using the Wilcoxon test. Patients with POCI evaluated with e-NIHSS had an average of 2 points higher than patients evaluated with classical NIHSS. The difference was statistically significant (P < .05), weighted by the new expanded items. CONCLUSIONS: The NIHSS is a practical scale model, with high reproducibility between trained, different examiners, focused on posterior circulation strokes, with the same total score and number of items of the existing NIHSS. The e-NHISS could improve the sensitivity of NIHSS in posterior circulation stroke and could have an impact on clinical trials, as well as on outcomes. Further studies are needed to investigate a larger number of patients and the correlation between the e-NIHSS score and neuroimaging findings.

Visual attention in posterior stroke and relations to alexia.

Impaired visual attention is common following strokes in the territory of the middle cerebral artery, particularly in the right hemisphere, while attentional effects of more posterior lesions are less clear. Commonly, such deficits are investigated in relation to specific syndromes like visual agnosia or pure alexia. The aim of this study was to characterize visual processing speed and apprehension span following posterior cerebral artery (PCA) stroke. In addition, the relationship between these attentional parameters and single word reading is investigated, as previous studies have suggested that reduced visual speed and span may explain pure alexia. Eight patients with unilateral PCA strokes (four left hemisphere, four right hemisphere) were selected on the basis of lesion location, rather than the presence of any visual symptoms. Visual attention was characterized by a whole report paradigm allowing for hemifield-specific measurements of processing speed and apprehension span. All patients showed reductions in visual span contralateral to the lesion site, and four patients showed bilateral reductions in visual span despite unilateral lesions (2L; 2R). Six patients showed selective deficits in visual span, though processing speed was unaffected in the same field (ipsi- or contralesionally). Only patients with right hemifield reductions in visual span were impaired in reading, and this could follow either right or left lateralized stroke and was irrespective of visual field impairments. In conclusion, visual span may be affected bilaterally by unilateral PCA-lesions. Reductions in visual span may also be confined to one hemifield, and may be affected in spite of preserved visual processing speed. Furthermore, reduced span in the right visual field seems to be related to reading impairment in this group, regardless of lesion lateralization.

An investigation of attentional contributions to visual errors in right "neglect dyslexia".

One type of error that is sometimes produced by patients with acquired dyslexia is the substitution of an orthographically similar word with letters that overlap the target either in early or late letter positions. When such errors affect the left sides of words, they are usually produced by patients with focal right hemisphere lesions who typically show evidence of left neglect in non-reading tasks. This pattern has thus been termed "neglect dyslexia". When the right sides of words are affected, however, patients frequently fail to show any signs of neglect in tasks other than reading. This study presents results from a patient with left hemisphere damage, and a very clear pattern of right "neglect" errors in reading, on a series of tasks testing attentional and imagery processes. Given the magnitude and consistency of the patient's reading errors, there was little evidence that these errors resulted from inattention to the right side of space or to the right side of an internally generated visual image. It is argued that the positional errors result from an impairment to an abstract ordinal code with graded activation of letter positions from first to last, and that this code is specific to tasks involving orthographic representations.

Confusion or delirium in patients with posterior cerebral arterial infarction.

OBJECTIVE: To identify the possible anatomic sites and risk factors for the development of confusion or delirium in patients with posterior cerebral arterial (PCA) infarction. MATERIALS AND METHODS: Twenty-nine patients aged 34-86 years with PCA infarction were divided into two groups: one with and the other without perturbed mentation. The clinical and laboratory data, including neuroimages, were retrospectively reviewed. Student-t, chi-square and Fisher's exact tests were performed for data analysis. RESULTS: Confusion or delirium tended to develop in the left (10/13) or bilateral (5/5) PCA infarction as compared to the right PCA infarction (3/15) (P< 0.05) and medial occipital-temporal gyri involvement was crucial for its development (P< 0.05). The results were also noted in the patients with first-ever stroke. Diabetes mellitus was the sole biochemical factor to be associated with confusion or delirium (P< 0.01). CONCLUSIONS: The involvement of the medial occipito-temporal gyri, especially on the left side was the pivotal factor for the development of confusion or delirium in patients with PCA infarction. Higher prevalence of diabetes mellitus was also observed in the group with mental perturbation.

Face imagery and its relation to perception and covert recognition in prosopagnosia.

BACKGROUND: Face imagery can access facial memories without the use of perceptual stimuli. Current data on the relation of imagery to the perceptual function and neuroanatomy of prosopagnosic patients are mixed, and little is known about the type of facial information patients can access through imagery. OBJECTIVE: The authors wished to determine 1) which lesions abolished face imagery in prosopagnosia, 2) if deficits in perceiving facial structure were paralleled by similar deficits in imagery, and 3) if covert recognition of faces correlated with the degree of residual imagery for faces. METHODS: The authors tested nine prosopagnosic patients who had been tested previously for perception of facial configuration and covert recognition of famous faces. The authors constructed a battery of 37 questions that asked subjects to imagine the faces of two celebrities and to choose which one had a certain facial property. Half were questions about facial features and half were about overall facial shape. RESULTS: Imagery was abolished only by anterior temporal lesions. Imagery for facial shape but not features was degraded by lesions of the right hemisphere's fusiform face area, which severely impaired perception of facial configuration. Feature imagery was degraded only when there was associated left occipito-temporal damage. Covert recognition was found when either configural perception or imagery was severely damaged, but not when both were abnormal. In patients with impaired configural perception, covert recognition correlated with feature imagery, suggesting that feature-based processing may drive residual covert abilities in these patients. CONCLUSION: Although anterior temporal cortex may be the site of facial memory stores, these data also support hypotheses that perceptual areas like the fusiform face area have parallel contributions to mental imagery. The data on covert recognition are consistent with a view that it is the residue of a partially damaged face-recognition network. Covert recognition may reflect the degree of damage across components of a network rather than mark a specific form of prosopagnosia or a dissociated pathway.

The anatomy of visual neglect.

The brain regions that are critically associated with visual neglect have become intensely disputed. In particular, one study of middle cerebral artery (MCA) stroke patients has claimed that the key brain region associated with neglect is the mid portion of the superior temporal gyrus (STG), on the lateral surface of the right hemisphere, rather than the posterior parietal lobe. Such a result has wide-ranging implications for both our understanding of the normal function these cortical areas and the potential mechanisms underlying neglect. Here, we use novel high resolution MRI protocols to map the lesions of 35 right-hemisphere patients who had suffered either MCA or posterior cerebral artery (PCA) territory stroke. For patients with MCA territory strokes, the critical area involved in all neglect patients was the angular gyrus of the inferior parietal lobe (IPL). Although the STG was damaged in half of our MCA neglect patients, it was spared in the rest. For PCA territory strokes, all patients with neglect had lesions involving the parahippocampal region, on the medial surface of the temporal lobe. PCA patients without neglect did not have damage to this area. We conclude that damage to two posterior regions, one in the IPL and the other in the medial temporal lobe, is associated with neglect. Although some neglect patients do have damage to the STG, our findings challenge the recent influential proposal that lesions of this area are critically associated with neglect. Instead, our results implicate the angular gyrus and parahippocampal region in this role.

Multiple perceptual distortions and their modulation in leftsided visual neglect.

There is an ongoing debate concerning the perception and neural representation of space in neglect. Four experiments are here reported designed to further investigate the nature of perceptual distortions and their modifiability in patients with neglect. In Experiment 1 it was found that neglect patients, in contrast to left- or right-hemisphere lesioned control patients and normal subjects, show similar distortions of perceived visual space when judging the extension of horizontal distances (space distortion) as compared to the horizontal size of objects (size distortion). Similar deficits were present in most neglect patients in a newly developed space bisection task. These results attest that neglect patients have perceptual distortions related to within-object (size) and between-object (distance) spatial processing in their horizontal plane. Objects were oversized by 33% and distances by 19% horizontally in neglect patients, whereas all control groups showed nearly veridical spatial coding (deviations<5%). In Experiment 2 the modifiability of these distortions was tested by the use of slow visual background motion. Leftward, coherent background motion transiently restored normal horizontal size and distance coding in neglect patients, whereas rightward motion aggravated the deficit significantly in the distance task, but not in the size task. None of the other subject groups showed any influence of background motion on spatial judgments. Experiment 3 evaluated possible effects of simultaneous vs successive stimulus presentation in perceptual distortions, thus modulating attentional factors. Neglect patients performed significantly better - although not normal - with a successive presentation of the spatial stimuli (2 s, 10 s delay) as compared to the simultaneous condition in the size judgment task, but not in the distance task. In contrast, this manipulation had no effects in any of the control groups. Experiment 4 reports more detailed results of subject J.S., a neglect patient with a right mediotemporal lesion, who showed a marked horizontal size distortion, but normal horizontal distance judgments. Despite some fluctuation in J.S.'s size judgments he showed a significant overestimation of horizontal object size by +22% to +40% across several test blocks and testing sessions. Thus, performance fluctuations due to attentional or other reasons cannot fully account for J.S.'s dissociation in size vs distance judgments. He thus shows that the visual coding of horizontal spatial extension within an object can be dissociated from that of the spatial extension between objects along the horizontal plane. Finally, performance in the three spatial tasks (used in Experiment 1) was found to correlate significantly with three typical tests of spatial neglect (line bisection, cancellation, copying, r=0.42-0.77), thereby indicating a significant relationship to the neglect syndrome.Together, the results of the four experiments are interpreted in support of multiple spatial-perceptual distortions in visual neglect, which are influenced by visual motion and attention. Perceptual distortions relating to objects and space between objects are present in most neglect patients, but may dissociate, as in case J.S. It is argued that these might reflect the existence of several, partially overlapping and diverging neural maps for the representation of different spatial attributes in the horizontal plane. Furthermore, it is hypothesized that these perceptual distortions constitute an important element of the spatial-perceptual deficits encountered in the syndrome, contribute to its severity, but are not the key deficit of the disorder.

Posterior cerebral artery territory infarct presenting as acute psychosis.

An 82-year-old man with a past medical history of hypertension was admitted to a psychiatric hospital for sudden onset of acute psychosis. He was then transferred to an acute geriatric unit for further evaluation. During the admission the patient was noted to be very restless, agitated and noisy and was shouting and screaming incessantly. This was interspersed with occasional short periods of calm and quiet. Clinically, no obvious focal neurological deficits were detected. A CT scan of the brain was performed and it revealed an acute infarct involving the area supplied by the left posterior cerebral artery. This was a rather atypical presentation for an infarct involving this area.