Cerebral blood flow in thalamic aphasia

Summary A 59-year-old man is reported, who became aphasic after left thalamic infarction, shown by CT. His speech was fluent, with reduced voice volume, impaired auditory and reading comprehension, verbal paraphasias but intact repetition skills. A single photon emission computed tomography (SPECT) scan to measure regional cerebral flow (rCBF) showed a reduction of flow in the parietotemporal areas of the left hemisphere. It is suggested that thalamic aphasia could result from structural subcortical damage with a homolateral functional cortical deficit leading to the specific aphasic disturbance.     

Mixed language dominance: insights from a case of unexpected fluent aphasia with semantic jargon resulting from massive left perisylvian lesion

We report a right-handed patient with a massive lesion in left perisylvian language cortex, who unexpectedly presented with fluent aphasia with semantic jargon. Language deficits were assessed with a comprehensive battery of language tests. Comprehension, naming, reading, and writing were severely impaired, and verbal expression was moderately fluent with semantic jargon. Although the patient’s lesion included brain areas typically essential for motor speech coordination, he was neither nonfluent nor apraxic. He exhibited strikingly unexpected aphasia with semantic jargon and prominent comprehension deficits, suggesting that this is a case of mixed dominance: the right hemisphere likely controls motor speech and basic syntactic skills, while the severely damaged left hemisphere controls semantic processing, predictably severely impaired.     

Aphasia caused by left paramedian thalamic infarction. Anatomo-clinical case

A 67 year-old right-handed man presented with an aphasia of acute onset associated to paralysis of vertical eye movements, mild cerebellar right dysmetria and right hemiparesis without hemianopia. CT scan showed two low density areas in the left thalamus and left occipital lobe. Neuropsychological examination revealed a non fluent aphasia with normal repetition, semantic paraphasias, perseverations and good comprehension of verbal and written commands. There was no alexia. Writing was impaired only by motor disturbances. Three weeks after the onset, tetraparesis and impairment of consciousness followed by a locked in syndrome supervened. Death occurred four months after onset. Neuropathological examination showed a left paramedian thalamic infarct involving the ventrolateral, dorso-medial and intralaminar nuclei, sparing the pulvinar. There was an occipital infarct sparing the calcarine scissura and multiple infarctions in the pons and the cerebellum. Broca's and Wernicke's areas were spared. We suggest that the involvement of medial nuclei could be partly responsible of language disturbances in thalamic aphasia.     

Amnesia, confabulation and nonaphasic misnaming after left thalamic infarct]

A 72-year-old right handed woman developed amnesia, confabulation and abnormal (bizarre) verbal response after the left thalamic infarction. Clinical features including disorientation, euphoria and various kinds of paraphasia coincided in nonaphasic misnaming. MR images showed that lesions involved the genu of the internal capsule, the anteroventral nucleus, the lateroventral nucleus, intralaminar nuclei, the mamillothalamic tract and the region around the ventral thalamus. 99mTc-HMPAO-SPECT revealed decreased uptake in the left frontal lobe, probably due to the disconnection from the thalamus. These findings suggest that the dysfunction of the thalamus (mainly ventrolateral) and the left frontal lobe caused the disturbance of the self-monitoring in the language use, which generated confabulation and nonaphasic misnaming in our case.     

Correlation of thalamic aphasia and cerebral blood flow]

Relations between linguistic deficits and cerebral blood flow (CBF) were studied in 20 cases of thalamic aphasia due to hemorrhage. Language analysis was based on BDAE, verbal intelligence quotient and verbal subtest of the memory quotient (Wechsler). CBF analysis (and of asymmetry index: AI) was done with 133 Xenon by SPECT technique in tomographic slices and in 15 areas of interest, i.e. cortical and deep areas. Relationships were analyzed by multiple correlations procedure and stepwise regression. Significant correlations were observed between linguistic results and AI of cortical but also deep areas (lenticular). Dynamic anomalies (fluency) were correlated with the IA and/or CBF of the frontal cortex. Verbal comprehension, naming and paraphasia were related to the AI of deep structures (insula and lenticular nucleus) and the AI of posterior cortex (temporo-occipital). Several correlations were found significant between results on verbal IQ of the WAIS and IA of the insula and lenticular nucleus.     

A left basal ganglia case of dynamic aphasia or impairment of extra-language cognitive processes?

We report the case of OTM who presented with dynamic aphasia following a stroke that occurred in the left basal ganglia. He showed drastically reduced spontaneous speech in the context of well preserved naming, repetition and comprehension skills. OTM was particularly impaired in generating words, sentences and phrases when cued by a stimulus allowing many response options. By contrast, when a single response was strongly suggested by a stimulus, he could generate verbal responses adequately. OTM's non-verbal response generation abilities varied across tasks. He performed in the normal range in a motor movement generation test and he produced as many figures as controls when tested on a figural fluency task. He showed, however, many perseverations on this test. Moreover in a random number generation task he produced more responses that were part of ascending and descending series of numbers. The patient's impairments are interpreted as a consequence of two deficits. The first of these consists of an inability to generate verbal responses particularly in situations of high competition and involves the function of left frontal regions. The second deficit is one of impaired novel thought generation as evidenced by perseverations. This second deficit has been proposed to be a function of basal ganglia damage.     

A left basal ganglia case of dynamic aphasia or impairment of extra-language cognitive processes?

We report the case of OTM who presented with dynamic aphasia following a stroke that occurred in the left basal ganglia. He showed drastically reduced spontaneous speech in the context of well preserved naming, repetition and comprehension skills. OTM was particularly impaired in generating words, sentences and phrases when cued by a stimulus allowing many response options. By contrast, when a single response was strongly suggested by a stimulus, he could generate verbal responses adequately. OTM's non-verbal response generation abilities varied across tasks. He performed in the normal range in a motor movement generation test and he produced as many figures as controls when tested on a figural fluency task. He showed, however, many perseverations on this test. Moreover in a random number generation task he produced more responses that were part of ascending and descending series of numbers. The patient's impairments are interpreted as a consequence of two deficits. The first of these consists of an inability to generate verbal responses particularly in situations of high competition and involves the function of left frontal regions. The second deficit is one of impaired novel thought generation as evidenced by perseverations. This second deficit has been proposed to be a function of basal ganglia damage.     

Perseverations in Alzheimer's disease: Memory slips?

Previous studies of verbal fluency tasks reported higher rates of repeated responses in Alzheimer's disease (AD) compared to elderly controls. The present investigation aimed at determining if perseverations are caused by word retrieval deficits or working memory deficits, both of which are commonly observed in AD. Based on current theories of lexical processing and working memory, we derived specific predictions concerning the lag between the first occurrence of a word and its repetition. With word retrieval deficits, repetitions are expected to be progressively less frequent at greater lags; conversely, with working memory deficits, repetitions should occur especially after long lags. These predictions were tested analyzing the performance of 392 AD individuals in verbal fluency tasks. The finding of lags that were significantly longer than would be expected by chance is consistent with the hypothesis that perseverations are primarily caused by working memory deficits. Specifically, we propose that perseverations stem from an impairment affecting the working memory mechanisms that control response monitoring. We also investigated the relationship between perseverations and other cognitive deficits observed in AD. We discuss the implications of our findings for understanding the nature of perseverations, the effects of working memory deficits in AD, and the neural correlates of working memory components.     

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.     

Language-related cognitive declines after left temporal lobectomy in children.

Presented is a case series demonstrating that clinically significant language-related cognitive declines not detected by intelligence quotient (IQ) testing occur after left temporal lobectomy in school-aged children. In this series, comprehensive preoperative and postoperative neuropsychologic evaluations were completed in eight school-aged patients who underwent temporal lobectomy (five left, three right) for temporal lobe epilepsy. Mean age at surgery was 13 years, 11 months +/- 2 years, 1 month. Testing included measurement of IQ, verbal learning, naming, visual memory, sight word recognition, reading comprehension, and calculation. All five left temporal lobectomy patients demonstrated significant language-related cognitive declines on postoperative neuropsychologic testing, including deficits in verbal IQ (one patient), verbal learning (four patients), naming (one patient), and reading comprehension (one patient). These deficits were clinically evident in four of the five left temporal lobectomy patients, leading to declines in educational performance. IQ testing alone did not reliably identify these deficits. No significant declines were found after surgery in three right temporal lobectomy patients. Average or high preoperative functioning may have predisposed patients to postoperative deficits in this series, whereas magnetic resonance imaging or pathologic abnormalities did not protect against postoperative deficits. Outcome studies of temporal lobectomy in childhood should use comprehensive neuropsychologic testing to identify cognitive deficits.     

Left thalamic infarction and disturbance of verbal memory: a clinicoanatomical study with a new method of computed tomographic stereotaxic lesion localization

A 41-year-old right-handed man developed disturbances of language and memory after a discrete thalamic infarction. Detailed neuropsychological assessment revealed deficits in verbal fluency, word finding, confrontation naming, and anterograde memory for verbal material. High-resolution computed tomography with stereotaxic lesion localization permitted the determination of the thalamic nuclei involved in the infarction. We suggest that the patient's problem in language and verbal memory reflected a defect in memory processing for verbal material during registration, retention, and retrieval, and that this defect probably resulted from a left anterior thalamic lesion affecting the ventrolateral nucleus, centromedian-parafascicular nuclei complex, internal medullary lamina, or mamillothalamic tract.     

Sensory aphasia after closed head injury.

A 51-year-old, right-handed male injured his head when drunk. After an initial mute state lasting for several hours, he exhibited fluent aphasia, impaired word finding, some verbal paraphasia and impaired verbal comprehension. A CT scan revealed a contusion in the left anterior temporal lobe. He was treated conservatively, and at the follow-up 6 months later, his sensory aphasia had recovered well. The relationship between closed head trauma and aphasia is reviewed with special attention to its nature and clinical course.     

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.     

Outcome of "well-differentiated jargon" and related lesions]

We introduce "well-differentiated jargon" as a new type of jargon with two relevant cases. To give a simple and clear framework to a classification of jargon, we define three types of jargon as follows: Under the condition that utterance does not decrease remarkably, (1) If approximately 90% of whole utterance consists of real words and clear syntactic structure though incomprehensible, it is "well-differentiated jargon". (2) If approximately 90% of whole utterance consists of unclear phonemes or phonemes that are not able to divide into words, it is "undifferentiated jargon". (3) If in-comprehensible utterance does not belong to any type of jargon above, it is "moderately-differentiated jargon". In this line of definition, "well-differentiated jargon" is the most highly differentiated jargon. The following cases are the examples of "well-differentiated jargon": Case 1 was a 67-year-old woman with head injury of the left orbital cortex, prefrontal cortex, and temporal pole; Case 2 was a 64-year-old man with brain atrophy in bilateral frontal cortex and bilateral (right dominant) anteroinferior temporal cortex after meningoencephalitis. Within six months after onset, they showed characteristic verbal aspects as follows; transcortical sensory aphasia; utterance with a lot of perseverative error, irrelevant words, unnecessary qualifiers during the naming task; well-preserved syntactic structure in a sentence with a few neologism. One year after the first verbal assessment, the performance of Case 1 improved almost entirely, whereas characteristic utterance was still observed in Case 2. These results suggest that "well-differentiated jargon" can be caused by lesions in anteroinferior temporal cortex and prefrontal cortex with preserved language area, where involve more anterior region than that of classical jargon. These two cases cannot belong to any classical jargon, and then we insist the adoption of new type of jargon, "well-differentiated jargon".     

Cortisol, learning, memory, and attention in relation to smaller hippocampal volume in police officers with posttraumatic stress disorder.

BACKGROUND: A proposed explanation for memory impairments in posttraumatic stress disorder (PTSD) is stress-induced hippocampal damage due to elevated cortisol levels. We have previously reported smaller hippocampi in police officers with PTSD. In this study, we examined changes in and associations between cortisol, learning, memory, attention, and hippocampal volume in PTSD. METHODS: In a case-matched control study, 12 police officers with PTSD and 12 traumatized police officers without lifetime PTSD were examined with magnetic resonance imaging (for hippocampal volume), salivary cortisol tests, and neurocognitive assessments. RESULTS: Significantly smaller hippocampi and higher early morning salivary cortisol levels were found in PTSD. Subjects with PTSD performed worse on a delayed visual memory recall task at trend level, and made more perseverations and intrusions on a verbal memory task. Negative correlations were found between PTSD symptom severity and immediate recall function, and between re-experiencing symptoms and left hippocampal volume. A positive correlation was found between salivary cortisol level in early morning and right hippocampal volume; however, hippocampal volume did not correlate with memory. CONCLUSIONS: Smaller hippocampi, higher cortisol levels, and memory impairments were associated with PTSD but were not directly correlated to one another. Memory impairments in PTSD do not seem to be a direct consequence of hippocampal size.     

Ictal paraphasia induced by language activity

Four patients with ictal speech disturbance were studied. Their seizures featured isolated, or series of, brief episodes of fluent paraphasia, paragraphia, and comprehension deficit. These episodes were often induced by language activity. Six patients with ictal paraphasia or paragraphia, as a recurrent habitual seizure, are reported in the literature. All ten cases, including the four cases described here and the six cases reported in the literature, featured patients who uttered meaningless speech fluently or displayed paragraphia. The syllables uttered during seizures contained many neologisms and resembled the neologistic jargon of patients with fluent aphasias of the Wernicke type. Nine patients had clusters or status of brief seizures and four patients had auditory hallucination as an ictal event. The seizures in six patients were easily induced by the use of language. Seizure focus was on the left side in all patients mentioned. The possibility of another type of language-induced seizures than those seen in reading epilepsy or language-induced epilepsy is suggested in which myoclonias of the jaw and face, or upper extremities are the main seizure types.     

Perseveration in aphasia

We developed a battery of tests to evaluate the relationship of perseveration to aphasia, and tested 44 subjects (18 with aphasia, 13 with right hemispheric lesions, 13 normal controls). Several major findings emerged: left hemispheric, posteriorly located, aphasia producing lesions also produced abundant perseverations, both verbal and non-verbal, which were primarily recurrent in type; right hemispheric lesions produced few perseverations, and these were primarily of the continuous type; more than half of the verbal recurrent perseverations of aphasia on a naming task were semantic in nature. We conclude that recurrent perseveration has a special, perhaps integral, link to language disorders of aphasia, particularly fluent aphasia associated with posterior lesions.     

Perisomatic thalamic axotomy after diffuse traumatic brain injury is associated with atrophy rather than cell death

Morbidity and mortality associated with traumatic brain injury (TBI) stem from diffuse axonal injury (DAI) throughout subcortical and brainstem white matter and subcortical nuclei. After midline fluid percussion brain injury, DAI in the thalamus includes perisomatic axotomy and resembles human post-traumatic pathology where the degree of morbidity correlates with thalamic damage. After axotomy, acute somatic perturbations resolve and appear compatible with cell survival; however, the long-term fate of neurons in an area with perisomatic axotomy is unknown. From brain-injured and uninjured rats at 1, 7 and 28 days after injury (injury, n = 5/group; sham, n = 4), alternate sections were immunostained for amyloid precursor protein (APP) to detect perisomatic axotomy or Giemsa stained for quantification of neuronal number, neuronal density, regional volume, and neuronal nuclear volume using design-based stereology. One day postinjury, APP-immunoreactive axons were identified consistently within the perisomatic domains of thalamic neurons of the ventral basal complex. Bilateral systematic-random quantification of the ventral basal complex indicated a significant reduction in neuronal density (number per mm, but not number alone) at 1 week after injury, compared with sham and 1 day postinjury. Furthermore, by 1 day and persisting through 1 week after injury, the mean neuronal nuclear volume was atrophied significantly compared with sham. Therefore, diffuse TBI results in early perisomatic axonal injury followed by neuronal atrophy in the ventral basal complex, without gross degeneration. Enduring atrophy in thalamic relays could underlie circuit disruption responsible for post-traumatic morbidity.     

Processing of audiovisual stimuli in aphasic and non-brain-damaged listeners

Abstract

We report the case of a 65-year-old monolingual right-handed man with 5 years of schooling who, after partial recovery of Wernicke's aphasia due to a left temporoparietal lesion, was affected by a second stroke involving the homologous regions in the right hemisphere. The clinical picture after the second stroke was characterized by a severe ‘glossolalic’ jargon: auditory comprehension was only moderately impaired. This case supports the association of severe, disinhibited jargon production with bihemispheric lesions. Furthermore, it indicates that partially preserved auditory comprehension can be found in a patient with bilateral temporal lesions involving Wernicke's area and its mirror region in the right hemisphere.     

Ipsilateral ptosis as main feature of tuberothalamic artery infarction

Tuberothalamic artery infarction (TTAI) results mainly in a myriad of neuropsychological symptoms such as memory impairment, euphoria, apathy, verbal perseverations, constructional apraxia and lack of spontaneity. Language disturbances, acalculia, buccofacial and limb apraxia occur prominently after left TTAI while visual spatial processing deficits and hemispatial neglect occur prominently after the right one. Some cases of TTAI causing Horner’s syndrome in addition of these wide-ranging neurobehavioral symptoms have been reported. Here, we report a case of TTAI with an ipsilateral ptosis as main clinical manifestation. This finding suggests that a Horner’s syndrome can be the main feature of TTAI when neuropsychological manifestations are inconspicuous.