Thalamic aphasia associated with mitochondrial encephalopathy,lactic acidosis,and stroke-like episodes: A case report

BackgroundMitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) with aphasia is a rare disorder, with the associated aphasia reported as either Wernicke’s or Broca’s. Herein, we report a patient with MELAS complicated by thalamic aphasia.CaseA 15-year-old right-handed girl presented with headache, nausea, right homonymous hemianopsia, and aphasia. She could repeat words said by others, but had word-finding difficulty, paraphasia, and dysgraphia. Brain MRI revealed abnormal signals from the left occipital lobe to the temporal lobe and left thalamus, but Wernicke’s area and Broca’s area were not involved. Additionally, she had short stature, lactic acidosis, bilateral sensorineural hearing loss, and a maternal family history of diabetes and mild deafness. Based on clinical findings and the presence of a mitochondrial A3243G mutation, she was diagnosed with MELAS. With treatment, the brain MRI lesions disappeared and her symptoms improved. Her aphasia was classified as amnesic aphasia because she could repeat words, despite having word-finding difficulty, paraphasia, and dysgraphia. Based on MRI findings of a left thalamic lesion, we diagnosed her with thalamic aphasia.ConclusionThalamic aphasia may be caused by MELAS. Assessment of whether repetition is preserved is important for classifying aphasia.     

Brain stem glioma in childhood: acute hemiplegic onset

Two children, age seven and 16 years, are described with the abrupt onset of a pure motor hemiplegia as the initial manifestation of a brain stem neoplasm. Subsequent rapid neurological deterioration localized the lesion to the brain stem and glioblastoma multiforme was diagnosed by surgical biopsy. It is suggested that brain stem gliomas with this unusual presentation are likely to be highly malignant and prone to rapid bulbar deterioration.     

Thalamic Lesions and Aphasia or Neglect

Purpose of Review

When the thalamus is damaged, not only are there neurological symptoms such as sensory impairment, hemianopia, or motor control disorders, but there are also various neuropsychological symptoms. We discuss the basic anatomy and function of the thalamus followed by a discussion of thalamic aphasia and hemineglect.

Recent Findings

Subcortical lesions in patients with hemineglect involved the anatomical network directly linked to the superior temporal gyrus. Furthermore, the pulvinar, part of the thalamus, may be associated with hemineglect. General linguistic tasks activated the thalami, depending on the difficulty, as well as the frontal and temporal lobes. The thalamus may play a role in language and be involved in the activation of cortical language areas, and in the linguistic integration function via verbal memory and semantic mechanisms.

Summary

Thalamic lesions are associated with aphasia and hemineglect. It is possible the mechanisms and such neuropsychological may be different depending on the size and site of the thalamic lesion.

     

Secondary thalamic atrophy related to brain infarction may contribute to post-stroke cognitive impairment

Background and purposeThe thalamus is a key brain hub that is globally connected to many cortical regions. Previous work highlights thalamic contributions to multiple cognitive functions, but few studies have measured thalamic volume changes or cognitive correlates. This study investigates associations between thalamic volumes and post-stroke cognitive function.MethodsParticipants with non-thalamic brain infarcts (3-42 months) underwent MRI and cognitive testing. Focal infarcts and thalami were traced manually. In cases with bilateral infarcts, the side of the primary infarct volume defined the hemisphere involved. Brain parcellation and volumetrics were extracted using a standardized and previously validated neuroimaging pipeline. Age and gender-matched healthy controls provided normal comparative thalamic volumes. Thalamic atrophy was considered when the volume exceeded 2 standard deviations greater than the controls.ResultsThalamic volumes ipsilateral to the infarct in stroke patients (n=55) were smaller than left (4.4 ± 1.4 vs. 5.4 ± 0.5 cc, p < 0.001) and right (4.4 ± 1.4 vs. 5.5 ± 0.6 cc, p < 0.001) thalamic volumes in the controls. After controlling for head-size and global brain atrophy, infarct volume independently correlated with ipsilateral thalamic volume (β= -0.069, p=0.024). Left thalamic atrophy correlated significantly with poorer cognitive performance (β = 4.177, p = 0.008), after controlling for demographics and infarct volumes.ConclusionsOur results suggest that the remote effect of infarction on ipsilateral thalamic volume is associated with global post-stroke cognitive impairment     

Subcortical aphasia: three different language disorder syndromes?

The study analyses clinical presentation of language functions of 32 patients with subcortical aphasia induced by stroke. The patients have been divided into three groups according to neuroanatomic localization of the lesion, defined by CT and MRI examination (striato-capsular aphasia, aphasia associated with white matter paraventricular lesions and thalamic aphasia). The following batteries and tests were used: the neurologic examination, CT scan, MRI, Doppler ultrasound, Mini Mental State Examination, Boston Diagnostic Aphasia Examination (BDAE), Boston Naming Test (BNT), Token Test and Verbal Fluency Test. Clinical presentation of subcortical aphasias is characterized with preserved repetition, however, some groups differ by certain specific features of language impairment. Striato-capsular aphasia and aphasia associated with white matter paraventricular lesions are characterized with lack of speech fluency, occurrence of literary paraphasias, mainly preserved comprehension and naming. Thalamic aphasia, however, is characterized with fluent output, impaired comprehension and naming with predominant verbal paraphasias. The specific features of language impairment suggest that subcortical structures contribute to language organization. Considering the results of language tests we presume that the most prominent feature in striato-capsular aphasia is phonetic impairment of language, opposite to thalamic aphasia where lexical-sematic processing seems to be affected.     

Fatal glioblastoma after Gamma Knife radiosurgery for arteriovenous malformation in a child

We describe a fatal case of glioblastoma multiforme that was induced by Gamma Knife radiosurgery (GKS; Elekta AB, Stockholm, Sweden) for an arteriovenous malformation (AVM). A 4-year-old girl presented with repeated convulsions. Imaging studies revealed an AVM located in the right thalamus. One year after initial symptoms, GKS was performed to obliterate the nidus. The maximum and marginal radiation doses were 32 and 16 Gy, respectively. Seventy months after GKS, the patient represented with severe headache. MRI showed a poorly demarcated tumor with heterogeneous gadolinium enhancement in the right thalamus and adjacent to the white matter of the temporal lobe. After a generalised convulsion, the patient deteriorated into a deep coma. CT scans showed severe brain swelling with intratumoral hemorrhage. An emergency craniotomy was performed, and the hematoma was removed. During this surgery, a tumor mass, which was found adjacent to the hematoma, was resected. Microscopic examination revealed glioblastoma multiforme. Despite intensive treatment, the patient died 1 month after surgery. A GKS-induced secondary tumor is a rare but serious complication. It is important to be aware of the adverse effects of GKS, including secondary neoplasms, before its clinical application, especially in young patients.     

Occupational head injury and subsequent glioma

We report the case of a policeman who suffered a severe head injury to the right temporoparietal lobe while driving a police car. Four years later, the patient developed a neoplasm at the precise site of the meningocerebral scar. Histological examination confirmed a glioblastoma multiforme adjacent to the dural scar. Radiological documentation of the absence of tumor at the time of injury, exact localization of the neoplasm in the injured cerebral area, and latency of the cancer supported the hypothesis of a causal relationship with brain trauma. Physicians faced with brain neoplasms in adults should carefully investigate the patient's personal history of head trauma. When a relationship with occupational head injury is probable, reporting of suspect occupational illness is compelling. Received: 10 September 2002 / Accepted in revised form: 7 January 2003 Correspondence to: D. Mei     

Metástasis medulares de gliosarcoma. Presentación de un caso y revisión de la literatura

IntroductionGliosarcoma is a rare neoplasm of the central nervous system, similar to glioblastoma multiforme. In contrast to glioblastoma, it is characterised by its propensity for extracranial metastasis (11% of the cases) due to its sarcomatous component. Intramedullary metastasis from primary gliosarcoma is extremely rare.Case reportA patient who had surgery for primary cerebral gliosarcoma developed paraparesis during the course of the disease. A magnetic resonance image showed an intramedullary spinal cord metastasis requiring surgical treatment. This article reviews the literature on intramedullary spinal cord metastasis from gliosarcoma, and highlights the characteristics, treatment and overall survival.ConclusionsOnly 4 cases of intramedullary gliosarcoma metastasis are described in the literature. This extremely rare entity should be suspected with the onset of spinal cord symptoms during the course of primary cerebral gliosarcoma.     

Non-persistent "doll phenomenon" in a patient with right thalamic infarction]

An 81-year-old right-handed woman was admitted because of acute dysarthria and left hemiparesis. She had lived herself without aids until the admission. On neurological examination she was confused and disoriented. She was ambulant, but had mild dysarthria and mild left hemiparesis. Neuropsychological tests showed severe impairment of memory, mild impairment of visual cognition, decreased fluency of word recall and mild paramnesia, but no acalculia, agraphia, aphasia or apraxia. MRI of the brain showed small infarction in the right anterior thalamus. 123I-IMP SPECT demonstrated a decrease in CBF of the thalamus, basal ganglia and frontal lobe on the right. During admission, she always played with a doll as if she took it as a real baby. This peculiar symptom. "doll phenomenon" continued for approximately three months later. The "doll phenomenon" usually appears in demented patients with diffuse mental deterioration or dysfunction of the frontal lobe. The present patient had not been demented until the onset of the thalamic infarction, and disturbance of cognition caused by the right thalamic infarction probably produced the "doll phenomenon".     

Expression of JC virus T-antigen in a patient with MS and glioblastoma multiforme

OBJECTIVE: To investigate the presence of human polyomavirus JC virus genome and the expression of the viral oncoprotein T-antigen in neoplastic cells of a patient with MS and a glioblastoma multiforme. BACKGROUND: The postmortem examination of an immunocompetent patient with a neurologic disorder revealed the concurrence of MS plaques in the white matter of the brain and a glioblastoma multiforme in the region of the thalamus. METHODS AND RESULTS: PCR analysis of DNA from demyelinated plaques and the tumor area using primers derived from specific regions of the JC virus genome revealed the presence of viral DNA corresponding to the viral early and late genes. Further examination of the samples for the JC virus regulatory region identified the presence of sequences identical to JC virus Mad-4 and JC virus W1 viral isolates in the tumor and the demyelinated regions. Results from immunohistochemistry showed the detection of the viral early protein, T-antigen, and the cellular tumor suppressor protein, p53, in the nuclei of neoplastic cells. Interestingly, expression of T-antigen, but not p53, was observed in neurofilament-positive cells with neuronal morphology and in glial fibrillary acidic protein-positive astrocytes in the cortex juxtaposed to the MS plaques. Examination of viral late gene expression by immunohistochemistry showed no evidence for viral capsid proteins, thus ruling out productive replication of JC virus in the tumor and MS demyelinated plaques. CONCLUSIONS: These observations provide molecular and clinical evidence of the association of JC virus in the brain of a patient with concurrent glioblastoma multiforme and MS.     

Language and memory disturbances from mesencephalothalamic infarcts. A clinical and computed tomography study

Three right-handed subjects presented impairment of consciousness, paralysis of vertical gaze, aphasia and memory disturbances. Computed tomography scans showed low-density lesions in the paramedian areas of the left thalamus. Neuropsychological examination revealed a fluent aphasia in one patient and a nonfluent in two; all had paraphasias and perseveration. Comprehension, repetition and writing were normal. In the literature on so-called thalamic aphasia only a few cases are reported with involvement of the paramedian nuclear complex.     

Semantic memory deficit with a left thalamic infarct

Previous studies of patients with thalamic lesions have reported consistent word finding difficulties without a proposed etiology. The authors describe a patient with a focal left thalamic infarct, pronounced word finding problems, and a relatively selective impairment in semantic memory for object recall from features. The thalamus is proposed to facilitate electrical activity between brain regions that encode object features, resulting in object recall. Thalamic dysfunction disrupting object recall is a plausible etiology for impaired word finding in some patients.     

Increased Laterality of the Thalamus in Children and Adolescents with Asperger's Disorder: An MRI and Proton Spectroscopy Study

Objective

Thalamic abnormalities have been reported in people with pervasive developmental disorders (PDD) including Asperger''s Disorder (ASP). The aim of the present study was to compare the volume and volume fraction of the thalamus and the metabolite concentrations in children and adolescents with ASP using the magnetic resonance imaging and proton magnetic resonance spectroscopy. Additionally, the relationships between thalamic abnormalities and clinical features were examined.

Methods

Volume and volume fractional and metabolic measurements of bilateral thalamus were collected from 15 boys with ASP with a total IQ over 70 (age range 7-18 years, mean age 11.6±3.79 years), and 15 healthy controls matching age, sex and IQ. The thalamic volumes, hemisphere volumes and total brain volumes (TBV) were estimated using the stereological methods on magnetic resonance images. Chemical metabolites of thalamus were evaluated by ¹H spectroscopy.

Results

No differences in thalamic volumes, volume fractions and metabolites were observed between the groups. There were significant correlation between thalamic volume and total brain volume in both groups. The ASP group showed a significant left-minus-right thalamus difference as well as a significantly greater laterality index. In addition, a significant correlation between the laterality index and Autism Behavior Checklist language scores was observed.

Conclusion

Findings from this investigation point to a significant increase in laterality of the thalamus and a relationship with language problems in individuals with ASP. Our findings suggest that thalamic abnormalities may be related to mild language problems observed in ASP.     

Bilateral thalamic damage,cortical hypometabolism and behavioural disturbances

Thalamic damage could be responsible for reduced metabolism in anterior cortical areas. In order to investigate an anatomical lesion and impairment of regional blood flow (rCBF) in distant cortical areas, we studied by magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) a patient with bilateral thalamic infarction, who presented with sudden consciousness impairment, drowsiness, gaze paralysis, dysphagia and bilateral Babinski sign. Three weeks later the neurological symptoms disappeared, but a severe mental deterioration was evident MRI showed thalamic bilateral damage of posterior and medial areas, involving part of the pulvinar, more evident for the right thalamus. A ^99mTc-HMPAO SPECT showed a decrease of rCBF over frontal and parietal regions, more evident for the right hemisphere. Six months later a severe memory impairment was still evident and MRI and SPECT picture were unchanged. The persistent memory defect could be related to a loss of cortical activation following the thalamic damage. The absence of primary lesions of cortical regions on CT scan and MRI and the neuroanatomical considerations on the diffuse projections running from medial nuclei and pulvinar to large parts of anterior neocortex supported this hypothesis.     

Dynamic-intentional thalamic aphasia: a failure of lexical-semantic self-activation

Background: Previous research has described patients with aphasia from thalamic lesions, some of whom were non-fluent with intact comprehension, others who were fluent with impaired comprehension, and some of whom are non-fluent with impaired comprehension. Whereas these three subtypes usually have normal repetition, they had impaired naming, suggesting a deficit in lexical (phonological word forms)-semantic processing. We report a patient with a left thalamic hemorrhage in which lexical-semantic representations appear to be intact but the patient demonstrates an inability to spontaneously activate his lexical-semantic system Methods: A 82-year-old, right-handed man presented with decreased verbal fluency and memory loss following a thalamic hemorrhage. Neuropsychological assessment revealed significant decrements in verbal fluency with intact naming, comprehension, repetition and vocabulary. Conclusions: To the best of our knowledge this pattern of language disturbance, which mirrors dynamic aphasia induced by frontal lesions, has not previously been described with thalamic injury. The thalamus has strong connections with the frontal lobe and rather than degradation of lexical-semantic representations, this patient's thalamic lesion probably induced frontal lobe dysfunction with a failure to spontaneously active lexical semantic representations.     

High-grade dural arteriovenous fistula simulating a bilateral thalamic neoplasm

Dural arteriovenous fistulae (dAVF) provide a diagnostic challenge and must be part of a broad differential in pursuit of a difficult diagnosis or unusual presentation. This case report demonstrates an initially misguided diagnosis of bilateral thalamic neoplasm and demonstrates the importance of continued pursuit until the correct diagnosis is obtained. Moreover, to our knowledge, this is the first reported case of a dAVF simulating a bilateral thalamic neoplasm. We present a patient with a provisional diagnosis of bilateral thalamic neoplasm based on clinical history and an advanced imaging workup including MR spectroscopy. Subsequent biopsy suggested venous congestion, hypoxia, and edema without neoplasia. Routine post-operative CT the following day revealed suggestion of dAVF due to the presence of residual contrast from prior unrelated abdominal CT. Cerebral angiography eventually revealed a Cognard grade IIb dAVF. Trans-arterial Onyx embolization resulted in a dramatic clinical and radiographic improvement. This case highlights an unusual presentation and challenging diagnosis of a dAVF and the importance of pursuing the correct diagnosis.     

Subjective cognitive-affective status following thalamic stroke

Previous patient studies suggest that thalamic stroke may yield persistent deficits in several cognitive domains. At present, the subjective dimension and everyday relevance of these impairments is unclear, since many patients with thalamic stroke only show minor changes on physical examination. Here, we have studied subjective consequences of focal thalamic lesions. A sample of 68 patients with a history of ischemic thalamic stroke was examined by using established clinical self-report questionnaires assessing memory, attention, executive functions, emotional status and health-related quality of life. In order to control for general factors related to cerebrovascular disease, self-reports were compared to an age-matched group of 34 patients with a history of transient ischemic attack. Thalamic lesions were co-registered to an atlas of the human thalamus. Lesion overlap and subtraction analyses were used for lesion-to-symptom mapping. When both patient groups were compared, no significant differences were found for either questionnaire. However, when subgroups were compared, patients with infarctions involving the posterior thalamus showed significant emotional disturbances and elevated anxiety levels compared to patients with more anterior lesions. Our findings thus point to the existence of a persistent affective impairment associated with chronic lesions of the posterior thalamus. This syndrome may result from damage to connections between medial pulvinar and extra-thalamic regions involved in affective processing. Our findings suggest that the posterior thalamus may contribute significantly to the regulation of mood.     

Neuropsychological profile of bilateral paramedian infarctions: Three cases

Introduction: The thalamus is one of the strategic diencephalic structures of the human brain. The artery of Percheron, an asymmetrical common trunk arising from a P1 segment of the posterior cerebral artery, is a peculiar presentation of the three variants involved in the irrigation of the paramedian thalamic territory. Occlusion of this artery results in bilateral median thalamic infarction. The paramedian syndrome includes an acute loss or reduction of consciousness, often associated with oculomotor and neuropsychological disturbances. Patients and methods: We present three cases of bilateral paramedian thalamic infarction with onset of acute coma, followed by fluctuations in the level of consciousness, memory, and behavioural alterations. A neuroradiological study with MRI identified individual thalamic nuclei, and a complete neuropsychological study was performed one month after onset of ictus. Results: One of the patients showed severe memory and executive function impairments without improvement of vertical gaze palsy. The other two patients presented with mild executive dysfunction with complete resolution of neurological symptoms. Neuroimaging results showed a bilateral lesion of the dorsomedial nuclei in the three patients. Conclusions: Severe amnesia has been associated with an affection of the structures of the paramedian thalamic territory. Presently, the role of the dorsomedial nucleus remains controversial, with the suggestion that memory deficits observed in this type of lesion could be secondary to executive function deficits. In our case, the patient with the most severe dysexecutive deficit presented the most severe memory impairments.     

Transcortical aphasia from ischaemic infarcts of the thalamus: a report of two cases.

Thalamic injury from various natural causes, including tumours an haemorrhage, has been reported to lead abnormalities of language. The pathophysiology of these language disorders remains controversial because the naturally occurring thalamic lesions often are associated with mass effects. Two patients are described with hypodense left thalamic lesions, shown by computed tomography, probably representing infarction. Both patients had aphasia, but neither had evidence of appreciable brain swelling or distortion, nor were cortical language areas damaged.     

Fluorescence-guided resection of primary and recurrent malignant gliomas with 5-aminolevulinic acid. Preliminary results

Background and purposeExtent of resection plays a key role in the treatment of malignant gliomas (MGs). Patients with complete glioma removal, followed by chemoradiation, obtain the longest overall and progression-free survival. Fluorescence-guided resection of MGs enables intraoperative visualization of glioma tissue and increases control of the resection. The authors present preliminary results of 5-aminolevulinic acid (5-ALA) application during the resection of primary and recurrent MGs.Material and methodsSix patients with either a suspected malignant glioma based on magnetic resonance imaging (MRI) or with recurrent glioblastoma multiforme were enrolled in the study. The extent of resection was calculated according to the postoperative MRI performed within 72 hours. Preoperative and early postoperative neurological status and Karnofsky Performance Scale (KPS) were compared.ResultsFluorescence of tumour tissue was observed in 5/6 patients (five with the histopathological diagnosis of glioblastoma multiforme and one with neurotoxoplasmosis and AIDS). Complete tumour resection was achieved in 5 patients. Postoperative KPS and neurological status deteriorated in 2 cases. Radiotherapy and chemotherapy did not interfere with the sensitivity of the fluorescence guided tumour visualization.ConclusionsFluorescence-guided resection of primary and recurrent MGs with 5-ALA improves control of the tumour resection. It enables the cytoreduction to be maximized but experience in neuro-oncological surgery is required to avoid serious, postoperative neurological deficits.