Response time as an index for selective auditory cognitive deficits

The full or partial recovery of cognitive functions following brain lesions is believed to rely on the recruitment of alternative neural networks. This has been shown anatomically for selective auditory cognitive functions (Adriani et al. 2003b). We investigate here behavioral correlates that may accompany the use of alternative processing networks and in particular the resulting increase in response times. The performance of 5 patients with right or left unilateral hemispheric infarction and 6 normal control subjects in sound identification, asemantic sound recognition, sound localization, and sound motion perception was evaluated by the number of correct replies and response times for correct and wrong replies. Performance and response times were compared across patients and normal control subjects. Two patients with left lesions were deficient in sound identification and sound motion perception and normal in sound localization and asemantic sound recognition; one patient with right lesion was deficient in sound localization and sound motion perception and normal in sound identification and asemantic sound recognition; deficient performance was associated with increased response times. The remaining 2 patients (1 with left, 1 with right lesion) had normal performance in all 4 tasks but had significantly longer response times in some (but not all) tasks. Patients with normal or deficient performance tended more often than normal subjects to give faster correct than wrong replies. We propose that increased response time is an indication of processing within an alternative network.

Neonatal cerebral infarction and neuromotor outcome at school age

OBJECTIVE

The aim of this study was to assess neuromotor function at school age in children who had cerebral infarction on neonatal magnetic resonance imaging (MRI).

DESIGN

Twenty-two children with evidence of cerebral infarction on neonatal brain MRI (18 with arterial infarction and 4 with border-zone lesions) were assessed at school age with a structured neurologic examination and the Movement Assessment Battery for Children, a battery of tests designed to assess motor function.

RESULTS

Of the 22 children, 6 (30%) had hemiplegia and a further 7 (30%) showed some neuromotor abnormality such as asymmetry on the neurologic examination (n = 4) or poor scores on the neuromotor test without any sign of asymmetry (n = 3). The remaining 9 children had a normal motor outcome. Hemiplegia was found only in children who had concomitant involvement of hemisphere, internal capsule, and basal ganglia on brain MRI. Children with involvement of the internal capsule, associated either with basal ganglia or hemispheric lesions, did not show hemiplegia but still had motor difficulties.

CONCLUSIONS

Our results suggest that although hemiplegia occurs in a relatively small proportion of children with neonatal cerebral infarction, other signs of neuromotor impairment can be present, and these become more obvious at school age when a more specific assessment can be performed. These results also suggest that the involvement of the internal capsule on neonatal MRI can predict the presence of these abnormalities.

Sound recognition and localization in man: specialized cortical networks and effects of acute circumscribed lesions

Functional imaging studies have shown that information relevant to sound recognition and sound localization are processed in anatomically distinct cortical networks. We have investigated the functional organization of these specialized networks by evaluating acute effects of circumscribed hemispheric lesions. Thirty patients with a primary unilateral hemispheric lesion, 15 with right-hemispheric damage (RHD) and 15 with left-hemispheric damage (LHD), were evaluated for their capacity to recognise environmental sounds, to localize sounds in space and to perceive sound motion. One patient with RHD and 2 with LHD had a selective deficit in sound recognition; 3 with RHD a selective deficit in sound localization; 2 with LHD a selective deficit in sound motion perception; 4 with RHD and 3 with LHD a combined deficit of sound localization and motion perception; 2 with RHD and 1 with LHD a combined deficit of sound recognition and motion perception; and 1 with LHD a combined deficit of sound recognition, localization and motion perception. Five patients with RHD and 6 with LHD had normal performance in all three domains. Deficient performance in sound recognition, sound localization and/or sound motion perception was always associated with a lesion that involved the shared auditory structures and the specialized What and/or Where networks, while normal performance was associated with lesions within or outside these territories. Thus, damage to regions known to be involved in auditory processing in normal subjects is necessary, but not sufficient for a deficit to occur. Lesions of a specialized network was not always associated with the corresponding deficit. Conversely, specific deficits tended not be associated predominantly with lesions of the corresponding network; e.g. deficits in auditory spatial tasks were observed in patients whose lesions involved to a larger extent the shared auditory structures and the specialized What network than the specialized Where network, and deficits in sound recognition in patients whose lesions involved mostly the shared auditory structures and to a varying degree the specialized What network. The human auditory cortex consists of functionally defined auditory areas, whose intrinsic organization is currently not understood. In particular, areas involved in the What and Where pathways can be conceived as: (1) specialized regions, in which lesions cause dysfunction limited to the damaged part; observed deficits should be then related to the specialization of the damaged region and their magnitude to the extent of the damage; or (2) specialized networks, in which lesions cause dysfunction that may spread over the two specialized networks; observed deficits may then not be related to the damaged region and their magnitude not proportional to the extent of the damage. Our results support strongly the network hypothesis.

Preservation of propositional speech in a pure anomic: the importance of an abstract vocabulary

We describe a detailed quantitative analysis of the propositional speech of a patient, FAV, who became severely anomic following a left occipito-temporal infarction. FAV showed a selective noun retrieval deficit in naming to confrontation and from verbal description. Nonetheless, his propositional speech was fluent and content-rich. To quantify this observation, three picture description-based tasks were designed to elicit spontaneous speech. These were pictures of professional occupations, real world scenes and stylised object scenes. FAV's performance was compared and contrasted with that of 5 age- and sex-matched control subjects on a number of variables including speech production rate, volume of output, pause frequency and duration, word frequency, word concreteness and diversity of vocabulary used. FAV's propositional speech fell within the range of normal control performance on the majority of measurements of quality, quantity and fluency. Only in the narrative tasks which relied more heavily upon a concrete vocabulary, did FAV become less voluble and resort to summarising the scenes in an manner. This dissociation between virtually intact propositional speech and a severe naming deficit represents the purest case of anomia currently on record. We attribute this dissociation in part to the preservation of his ability to retrieve his abstract word vocabulary. Our account demonstrates that poor performance on standard naming tasks may be indicative of only a narrowly defined word retrieval deficit. However, we also propose the existence of a feedback circuit which guides sentence construction by providing information regarding lexical availability.

Langfristige Lebensveränderungen und Belastungsfolgen bei Ehepartnern von Schlaganfallpatienten

OBJECTIVE

This study investigates the long-term effect of stroke on the quality of life and health of patients' spouses.

METHOD

Twenty-six spouses of stroke patients were interviewed by means of standardized questionnaires and qualitative interviews. The study participants had been living with the consequences of stroke for 3 years on average when the interviews were carried out.

RESULTS

A stroke is often followed by considerable changes in everyday life and by role shifts within the relationship. In particular, depressive and aggressive changes in the patient's behaviour are experienced as burdensome. In addition to impairments in quality of life, psychological and psychosomatic troubles can also from the burden experienced. Depressive symptoms are the main factor in these negative consequences: the more a patient is assessed as depressive, the more his/her spouse reports health problems and poor quality of life.

DISCUSSION

Long-term changes in everyday life and partnership can bring about significant chronic burden for the spouses of stroke patients. Hence, offers of support and counseling are required not only in the acute and post-acute stages of stroke, but also after inpatient rehabilitation has ended.

Chronic cognitive impairment following laterothalamic infarcts: a study of 9 cases

BACKGROUND

The occlusion of the lateral thalamic arteries leads to infarcts of ventrolateral thalamic nuclei, the ventroposterior nucleus, and the rostrolateral part of pulvinar, and produces hemisensory loss with or without hemiataxia. Cognitive impairment after such strokes has not been systematically studied.

OBJECTIVE

To determine the nature and the extent of long-lasting cognitive deficits following lateral thalamic strokes.

DESIGN

Case series.

SETTING

Neurology department, Lausanne University Hospital, Lausanne, Switzerland.

PATIENTS

Nine patients with hemisensory loss due to an isolated laterothalamic infarct.

MAIN OUTCOME MEASURES

Three to 6 months after stroke onset, standard neuropsychologic evaluation, including testing of language, ideomotor and constructive praxis, visual gnosis, spatial attention, learning abilities, and executive functions.

RESULTS

Six of 9 patients showed some degree of cognitive impairment. Executive functions tasks, particularly verbal fluency, were impaired in 5 patients (4 with right and 1 with left lesion). Learning and delayed recall in visuospatial and verbal tasks, but not in recognition, were impaired in 3 patients (2 with right and 1 with left lesion). Difficulties in visual gnosia were observed in 1 patient with right lesion while word-finding difficulties were observed in 1 patient with left lesion.

CONCLUSIONS

Our observations show that while learning, naming, and gnosic difficulties fit with the classical verbal/nonverbal dichotomy (left and right hemisphere, respectively), executive dysfunctions, including verbal fluency tasks, were more dominant after right thalamic infarcts. Although the observed deficits appeared to be less severe than those generally found with dorsomedial and polar thalamic strokes, the dominance of executive dysfunction suggests that ventrolateral thalamic lesions may disrupt frontothalamic subcortical loops.

[Initial status of patients and effects of rehabilitation after stroke--analysis of a patients' and a physicians' questionnaire in three neurological rehabilitation centres with a follow-up after 6 months]

Rehabilitation after stroke has to face specific problems when treating patients with more or less severe disabilities in cognition and communication. Correspondingly, stroke rehabilitation takes a special position within the larger field of rehabilitation, and relatively little is known outside the neurological scientific community about the status of patients at admission, the case mix in the centres and the short- and medium-term effects of rehabilitation. The present study describes in some detail the initial status in unselected samples of consecutive patients (n = 768) from three neurological rehabilitation centres. The description shows a very inconsistent picture in all centres, ranging from patients with no neurological deficits to patients needing intensive care. Across the centres, we found remarkable differences in case mix. In order to measure the effects of rehabilitation after stroke, an instrument was developed that combines a physicians' questionnaire aiming at an assessment of the severely disabled cases with a patients' questionnaire for the less severe cases for which the physicians' questionnaire would show "ceiling effects" so that improvements could no longer be depicted. The application of the instrument showed that about 50 % of the sample were not capable of answering the patients' questionnaire. For the patients with neurological deficits, the functional parameters of the physicians' questionnaire showed significant improvements at discharge that can be interpreted as "strong" effects (effect sizes 1.0-1.3). For the patients with less severe deficits (and usually in later stages of the rehabilitation process), the patients' questionnaire showed "strong" improvements on the somatic and psychosocial scales both at discharge and 6 months later. On the functional scales, however, only small improvements were found. Finally, predictors could be identified that explain a large amount of the variance for length of stay (R(2) =.42) as well as for the effects of rehabilitation (R(2) =.74). When comparing effects across rehabilitation units with differences of case mix, these predictors should be statistically controlled in order to assure fair comparisons.

Safety and efficacy assessment of chungpyesagan-tang for acute ischemic stroke

Chungpyesagan-tang is one of the most well-known traditional herbal formulations frequently used for treatment of acute stroke in Korea. Therefore, this study aims to assess the clinical safety and efficacy of chungpyesagan-tang on acute ischemic stroke. We recruited acute cerebral infarction subjects within 1 week after onset time. Then, we prescribed chungpyesagan-tang to an Oriental medical treatment group (OM-group) for 2 weeks and enrolled a Western medical treatment group (WM-group) which received only Western biomedical care as a control. In this study, the OM-group was composed of 75 subjects. However, 14 of them dropped out, as two had progressive stroke while 12 complained of diarrhea. Thus, 61 cases were included in the analysis and compared to the 76 cases of the WM-group. The improvement of OM-group was better than that of the WM-group according to the National Institute of Health Stroke Scale (NIHSS), but not by the Modified Barthel Index (MBI). There were no definite abnormalities on labortory safety asessment. Therefore, we suggest that chungpyesagan-tang may have therapeutic effects, acting to reduce the severity of stroke and improving functional recovery without definite hepatic or renal toxicity when given for the first 2 weeks after a stroke.

From what to where: neuropsychological evidence for implicit interactions between object- and space- based attention

Three experiments examined nonspatial extinction in G.K., a patient with bilateral parietal damage. Experiment 1 demonstrated nonspatial extinction (poor detection of a weak relative to a stronger perceptual group), even when the stronger group was less complex than the weaker group. Experiment 2 showed improved report of a letter falling at the location of the stronger group, but explicit judgments of the location of the letter were at chance. Experiment 3 replicated the object-cuing benefit, though G.K. could not discriminate whether a letter fell at the same location as the stronger perceptual group. The data indicate coupling between object- and space-based attention, so that spatial attention is drawn to the location occupied by the winner of object-based competition for selection. In this case, what cues where. This coupling operates implicitly, even when explicit location judgments are impaired.

Patterns of verbal long-term and working memory performance reveal deficits in strategic processing in children with frontal infarcts related to sickle cell disease

Frontal brain regions are thought to mediate strategic processes that facilitate memory. We hypothesized that children with frontal cerebral infarcts related to sickle cell disease (SCD) would exhibit impairments in long-term and working memory as a result of disruptions in strategic processing. Word-list learning and digit span tasks were used to assess verbal memory and strategic processing in 21 children with SCD without infarcts (controls) and in 10 children with SCD with frontal infarcts. On the word-list learning task, children with frontal infarcts performed more poorly in terms of learning and free recall, although recognition and cued recall were adequate; this pattern suggested intact encoding and storage with impaired retrieval. Children with frontal infarcts performed more poorly on backward digit span, although forward digit span was adequate; this pattern suggested intact maintenance with impaired manipulation of information in working memory. Overall, these findings support the notion that disruptions in strategic processing contribute to memory impairments in children with frontal infarcts.

Deficits of memory, executive functioning and attention following infarction in the thalamus; a study of 22 cases with localised lesions

The thalamus plays a crucial role in memory, executive functioning and attention. It remains, however, unclear whether thalamic structures have specific roles in each of these functions. We tested 22 cases of thalamic infarction, proven with MR imaging, using experimental and established neuropsychological tests. We performed a lesion-overlap study in standardised stereotactic space of patients sharing a certain deficit, corrected for the lesion distribution of patients without such deficits and determined the regions of interest using an atlas of the human thalamus. We checked for additional, non-thalamic, damage and for deficient comprehension and perception that would preclude interpretation of the results. Non-thalamic damage such as white matter lesions, hippocampal atrophy, sulcal widening and infarctions occur significantly more often in patients aged over 60. The patients with additional damage overlapped to a major degree with those who showed loss of orientation, or lack of comprehension of the test requirements. In the 10 patients judged 'clean', we observed a deficit of episodic long-term memory with relative sparing of intellectual capacities and short-term memory when the mammillo-thalamic tract was damaged. Lesions including the medial dorsal nucleus, midline nuclei and/or intralaminar nuclei accompany executive dysfunctioning. Reduced simple processing speed and attention are associated with age, but not with a particular structure in the thalamus. Complex attention deficits follow damage to the intralaminar nuclei.We conclude that the analysis of structure-function relationships must take into account extra-structure damage which may explain cognitive deficits. Separate thalamic structures are involved in memory, executive functioning and attention.

Benchmarking as everyday functional assessment in stroke recovery

OBJECTIVES

Functional assessment in stroke recovery extends beyond formal testing and evaluation. Stroke survivors themselves continuously engage in the process of reckoning their functional capacities as they go about their everyday lives. This process is called benchmarking. The aim of this article is to discuss and illustrate how it operates in three areas of experience--self-definition, comorbidity and age, and the tasks of daily life.

METHODS

Benchmarking data are drawn from in-depth qualitative interviews with male stroke survivors of various ages and from three ethnic groups (Hispanic, African American, and non-Hispanic White).

RESULTS

The results show that the benchmarking process is evident in all social categories in which survivors fall, but specific kinds of benchmarks may be more prominent in some categories than others.

DISCUSSION

The lessons provided by everyday functional assessment for understanding the stroke experience, as well as directions for further study, are discussed in the conclusion.

[The model of stroke induced by microsphere embolism in rats]

Cerebral infarction is induced by injecting 700-900 microspheres with a diameter of 50 microm into the right internal carotid artery of the rat. Approximately 82% of the rats with typical symptoms of stroke survived at fifteen hours after the injection of microspheres. Microsphere-induced cerebral embolism elicits the widespread formation of small emboli in the ipsilateral hemisphere and subsequent neuronal loss and/or the development of multiple infarct areas in the brain, particularly in the cortex, striatum, and hippocampus. Thus, this model is considered to mimic focal ischemia-induced human stroke or multi-infarct dementia. We have found that this model showed sustained decreases in cerebral blood flow and cerebral high-energy phosphates; accumulation of tissue lactate, glucose, and glycogen; changes in the activity of several enzymes in the tricarboxylic acid cycle; loss of mitochondrial phosphorylation activity; and decreases in neurotransmitters, acetylcholine, monoamines, and amino acids in the ipsilateral hemisphere. Accordingly, microsphere embolism is capable of inducing severe and sustained cerebral ischemia resulting in disturbances of the energy and neurotransmitter metabolism in the brain. Such ischemic damage leads to learning and memory dysfunction. This model provides useful information about the pathogenesis, prophylaxis, and therapeutics of cerebral ischemic diseases.

Effect of a novel free radical scavenger, edaravone (MCI-186), on acute brain infarction. Randomized, placebo-controlled, double-blind study at multicenters

Edaravone, a novel free radical scavenger, demonstrates neuroprotective effects by inhibiting vascular endothelial cell injury and ameliorating neuronal damage in ischemic brain models. The present study was undertaken to verify its therapeutic efficacy following acute ischemic stroke. We performed a multicenter, randomized, placebo-controlled, double-blind study on acute ischemic stroke patients commencing within 72 h of onset. Edaravone was infused at a dose of 30 mg, twice a day, for 14 days. At discharge within 3 months or at 3 months after onset, the functional outcome was evaluated using the modified Rankin Scale. Two hundred and fifty-two patients were initially enrolled. Of these, 125 were allocated to the edaravone group and 125 to the placebo group for analysis. Two patients were excluded because of subarachnoid hemorrhage and disseminated intravascular coagulation. A significant improvement in functional outcome was observed in the edaravone group as evaluated by the modified Rankin Scale (p = 0.0382). Edaravone represents a neuroprotective agent which is potentially useful for treating acute ischemic stroke, since it can exert significant effects on functional outcome as compared with placebo.

A double-blind, placebo-controlled study of sertraline in the prevention of depression in stroke patients

The authors tested the effect of sertraline in the prevention of poststroke depression. After experiencing an acute ischemic stroke, nondepressed patients (N=137) were randomly assigned to 12 months of double-blind treatment with either sertraline (N=70) or placebo (N=67). Kaplan-Meier analysis showed sertraline to have significantly superior prophylactic efficacy compared with placebo. Two definitions of clinical depression were used: total score >18 on the HAM-D(17) and score >or=9 on the HAM-D(6). Approximately 10% of the sertraline-treated group developed depression according to either definition, whereas 30% developed depression in the placebo group. On the HAM-D(6) the superiority of sertraline to placebo was demonstrated already after 6 weeks of therapy. Treatment was well tolerated; patients treated with sertraline experienced significantly fewer adverse events.

Posterior parietal cortex and the filtering of distractors

Neural systems for visual processing can focus attention on behaviorally relevant objects, filtering out competing distractors. Neurophysiological studies in animals and brain imaging studies in humans suggest that such filtering depends on top-down inputs to extrastriate visual areas, originating in structures important for attentional control. To test whether the posterior parietal cortex may be a necessary source of signals that filter distractors, we measured the ability of a patient with bilateral parietal lesions to discriminate the features of a target surrounded by distractors of variable contrast. In the presence of distractors, the patient was impaired at discriminating both grating orientation and faces, and the magnitude of the impairment increased with distractor salience. These attentional deficits are remarkably similar to those caused by damage to monkey extrastriate regions V4 andor TEO, which are thought to be recipients of top-down attentional feedback. In contrast to the effects of V4 and TEO lesions, however, the parietal lesions impaired performance even with widely spaced targets and distractors, a finding consistent with the projections of parietal cortex to visual processing areas covering a wide range of receptive field sizes and eccentricities.

Depression with anosognosia following a left subcortical stroke

Controversy exists about whether depression following stroke represents a biologically mediated change or a psychological reaction to the deficits. We present a patient with an acute isolated personality change and depression following a lacunar infarct of the left internal capsule, who was unaware of his affective change. His anosognosia for the depression, which was abrupt and not accompanied by cognitive impairments, suggests that post stroke depression, at least in this case, is better explained by a biological than a psychological model.

[Microangiopathic lesions of white matter. Quantitation of cerebral MRI findings and correlation with psychological tests]

AIM

The importance of vascular lesions in the white matter of the brain (WML) is viewed differently. Diagnostic evaluation is determined by experience and age-associated normal values are not available.

MATERIAL AND METHODS

One hundred fifty-two patients aged 68.8 years (range 50-89) were examined at a memory clinic using a magnetic resonance FLAIR sequence,which is sensitive for WML. The WMLs were entered with respect to size, localization, laterality, and density. The WML scores of 76 clinically and psychologically normal subjects with microangiopathic lesions and 27 patients with vascular dementia were correlated with psychological test results. The contribution of local WML scores to the differentiation between age-associated microangiopathy and vascular dementia was calculated using logistic regression analysis. Nonparametric monotonic regression was used to analyse the age-associated WML scores of both groups, taking individual age into account.

RESULTS

The WML scores correlated linearly with the age of psychologically normal subjects but with degree of dementia for those with vascular dementia, and it allowed differentiation between these two groups with an accuracy of up to 88% and specificity of approximately 95% with reference to the right frontal region. The odds ratios of the general and frontal WML scores were significantly different (1,102 and 1,400, respectively). Statistical significance of the age-associated WML scores varied for different age ranges.

CONCLUSION

It is possible to differentiate psychologically normal subjects with microangiopathic brain lesions from patients with vascular dementia on MRI when referring to frontal WML scores.

Agraphia with abnormal writing stroke sequences due to cerebral infarction

A 65-year-old, right-handed man presented with speech and gait disturbances. He was alert and cooperative, showing mild right hemiparesis and sensory disturbance. Spontaneous speech was fluent; object naming, word fluency and reading were fully preserved. Sentence repetition and verbal comprehension were mildly impaired. Writing was slow, hesitant and difficult for both spontaneous writing and dictation. Copying was better, although he had some difficulty in copying letters and also complex figures. Sequences of strokes in forming written characters were abnormal; strokes were formed by piecing together several fragments. Computed tomography and magnetic resonance imaging showed a subcortical infarct in the left frontoparietal region. Characteristics of agraphia resembled 'apractic agraphia' and agraphia may have resulted largely from loss or unavailability of the memory of motor patterns necessary for writing letters.

Principles of cross-modal competition: evidence from deficits of attention

How does the attentional system coordinate the processing of stimuli presented simultaneously to different sensory modalities? We investigated this question with individuals with neurological damage who suffered from deficits of attention. In these individuals, we examined how the processing of tactile stimuli is affected by the simultaneous presentation of visual or auditory stimuli. The investigation demonstrated that two stimuli from different modalities are in competition when attention is directed to the perceptual attributes of both, but not when attention is directed to the perceptual attributes of one and the semantic attributes of the other. These findings reveal a differentiated attentional system in which competition is modulated by the level of stimulus representation to which attention is directed.

Anti-Nogo-A antibody infusion 24 hours after experimental stroke improved behavioral outcome and corticospinal plasticity in normotensive and spontaneously hypertensive rats

Nogo-A is a myelin-associated neurite outgrowth inhibitory protein limiting recovery and plasticity after central nervous system injury. In this study, a purified monoclonal anti-Nogo-A antibody (7B12) was evaluated in two rat stroke models with a time-to-treatment of 24 hours after injury. After photothrombotic cortical injury (PCI) and intraventricular infusion of a control mouse immunoglobulin G for 2 weeks, long-term contralateral forepaw function was reduced to about 55% of prelesion performance until the latest time point investigated (9 weeks). Forepaw function was significantly better in the 7B12-treated group 6 to 9 weeks after PCI, and reached about 70% of prelesion levels. Cortical infarcts were also produced in spontaneously hypertensive rats (SHR) by permanent middle cerebral artery occlusion (MCAO). In the control group, forepaw function remained between 40% and 50% of prelesion levels 4 to 12 weeks after MCAO. In contrast, 7B12-treated groups showed significant improvement between 4 and 7 weeks after MCAO from around 40% of prelesion levels at week 4 to about 60% to 70% at 7 to 12 weeks after MCAO. Treatment in both models was efficacious without influencing infarct volume or brain atrophy. Neuroanatomically in the spinal cord, a significant increase of midline crossing corticospinal fibers originating in the unlesioned sensorimotor cortex was found in 7B12-treated groups, reaching 2.3 +/- 1.5% after PCI (control group: 1.1 +/- 0.5%) and 4.5 +/- 2.2% after MCAO in SHR rats (control group: 1.8 +/- 0.8%). Behavioral outcome and the presence of midline crossing fibers in the cervical spinal cord correlated significantly, suggesting a possible contribution of the crossing fibers for forepaw function after PCI and MCAO. The results suggest that specific anti-Nogo-A antibodies bear potential as a new rehabilitative treatment approach for ischemic stroke with a prolonged time-to-treatment window.

Development of selective verbal memory impairment secondary to a left thalamic infarct: a longitudinal case study

A 68 year old man suffered an acute dysphasic episode with persistent memory disturbance while taking part as a control in a longitudinal magnetic resonance imaging (MRI) study. A small new left thalamic infarct involving the mamillo-thalamic tract could be demonstrated on volumetric MRI, coinciding with the development of a selective verbal memory impairment. This suggests that lateralisation of cognitive processing of visual and verbal material exists at the thalamic as well as the cortical level. High resolution volumetric MRI may be helpful in demonstrating small subcortical infarcts that may not be seen using computed tomography or conventional MRI.