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Thomas Benke

Publications and source records attributed to Thomas Benke.

At least 19 recordsLinked to original sources
PubMed2006

How specifically do we learn? Imaging the learning of multiplication and subtraction.

The present functional magnetic resonance imaging (fMRI) study investigates modifications of brain activation patterns related to the training of two different arithmetic operations, multiplication and subtraction. Healthy young adults were trained in five sessions to answer multiplication and subtraction problems. In the following fMRI session, trained and new untrained problems closely matched for difficulty were presented in blocked order. Contrasts between untrained and trained operations showed stronger activation of inferior frontal and parietal regions, especially along the banks of the intraparietal sulcus. The reverse contrasts, trained minus untrained operations, yielded significantly higher activation in the left angular gyrus for multiplication but no significantly activated area for subtraction. This suggests that training leads to a reduction of general purpose processes, such as working memory and executive control in both operations, indicated by the decrease of activation in inferior frontal areas. For multiplication, however, the increase of activation in the left angular gyrus indicates a switching of cognitive processes. Trained subtraction therefore seems to lead to faster and more efficient strategies, while trained multiplication showed a shift from quantity-based processing (supported by the areas along the intraparietal sulci) to more automatic retrieval (supported by the left angular gyrus). The same training method caused changes in brain activation patterns that depended on the given operation. The effects of learning on the brain therefore seem not only to depend on the method of learning but also on its content.

Adult↗
PubMed2005

Prefrontal disturbances as the sole manifestation of simple partial nonconvulsive status epilepticus.

We describe a case of frontal lobe epilepsy with rare nocturnal generalized tonic-clonic seizures and repeated prolonged episodes of altered behavior lasting 1 to 2 days. The changes consisted of poor organizational strategies, impaired set shifting, emotional indifference, reduced motivation, and impairment of emotional decision making. Memory and consciousness were undisturbed, as she was able to follow her profession as a teacher. During the episode, the EEG was marked by right frontal rhythmical spikes and waves with spread to the homologous left region. Behavioral abnormalities and EEG changes were successfully treated with intravenous diazepam. The clinical representation can be ascribed to alterations of prefrontal-subcortical circuits, especially the anterior cingulate and orbitofrontal circuits. This unique case is classified as simple partial nonconvulsive status epilepticus with prefrontal disturbances as the sole manifestation.

Anticonvulsants↗
PubMed2005

Language and arithmetic--a study using the intracarotid amobarbital procedure.

The intracarotid amobarbital procedure is used as a standard procedure in presurgical evaluation to assess hemispheric lateralization of language and memory, but has not been applied to investigate numerical processing. Patients with medically intractable epilepsy (n=20) were consecutively recruited during a presurgical evaluation programme. All 14 patients with left-lateralized language showed better arithmetic performance with the left hemisphere (intracarotid amobarbital procedure right), while five out of six patients with bilateral or right-hemispheric language representation showed better performance with the right hemisphere (intracarotid amobarbital procedure left). Furthermore, in patients with left-lateralized language, an interaction between intracarotid amobarbital procedure and type of arithmetic operation was found. The study suggests a close association between language lateralization and hemispheric specialization for arithmetic processing.

Adult↗
PubMed2005

Hippocampal formation involvement in a language-activation task in patients with mesial temporal lobe epilepsy.

PURPOSE: The study aims to explore the contribution of the hippocampal formation to the retained language-comprehension network in patients with unilateral mesial temporal lobe epilepsy (TLE). METHODS: We performed a functional magnetic resonance (MRI) study based on a language comprehension paradigm in 45 right-handed patients with unilateral mesial TLE and 35 healthy control subjects. Activations in the hippocampal formations in both hemispheres were analyzed for each subject as well as for groups of left TLE, right TLE, and controls. RESULTS: In sum, 82% of TLE patients displayed hippocampal activations. A significant difference in hippocampal activation between left and right TLE was found: Right TLE patients showed increased activity in the left hippocampal formation compared with left TLE patients. In contrast, patients with left TLE did not show increased activity in the right hippocampal formation compared with right TLE patients. In comparison with a healthy control group, right TLE patients activated the left hippocampal formation to a greater extent, whereas patients with left TLE did not activate the right hippocampal formation to a greater degree. These findings point to an increased involvement of the left hippocampal formation during a language-comprehension task in right TLE patients. In contrast, left TLE in right-handed patients seems not associated with an enhanced involvement of the right hippocampal formation in retained language comprehension. CONCLUSIONS: These findings suggest that effective language comprehension in right-handed subjects with TLE depends on the involvement of the left hippocampal formation and underline the risks of postoperative language decline in patients with left TLE.

Adolescent↗
PubMed2004

Basal forebrain atrophy is a distinctive pattern in dementia with Lewy bodies.

We determined brain atrophy patterns in dementia with Lewy bodies and Alzheimer's disease using voxel-based morphometry, an indirect volumetry. Ten patients with dementia with Lewy bodies, 10 patients with Alzheimer's disease and 10 controls were included. All groups were matched for age; sex and global differences in voxel intensities were included as confounding covariates. We observed basal forebrain atrophy discriminating dementia with Lewy bodies from Alzheimer's disease. Compared to controls, atrophy of lateral prefrontal cortex and left premotor cortex was seen in dementia with Lewy bodies whereas atrophy of the medial temporal cortex, posterior parietal cortex, thalamus and temporo-occipital areas was observed in Alzheimer's disease. Atrophy of insular cortex was found in both patient groups.

Aged↗
PubMed2004

Number processing and basal ganglia dysfunction: a single case study.

Numerical processing has never been investigated in a case of Fahr's disease (FD) and only rarely in cases of basal ganglia dysfunction. The study describes the cognitive decline of a pre-morbidly high-functioning patient (medical doctor) affected by FD and his difficulties in number processing. A MRI scan revealed bilateral calcifications in the basal ganglia and a brain PET showed a massive reduction of glucose metabolism in the basal ganglia and both frontal lobes, but no other brain abnormalities. The patient's cognitive deficits included impairments in problem solving, in cognitive set shifting and in mental flexibility, as well as in verbal memory. These deficits are attributed to the disruption of the dorsolateral prefrontal circuit involving the basal ganglia. In number processing, the patient showed a severe deficit in the retrieval of multiplication facts, deficits in all tasks of numerical problem solving and in the execution of complex procedures. Importantly, he also showed a dense deficit in conceptual knowledge, which concerned all test conditions and all operations. The findings confirm the predictions of the triple code model in so far, as a disruption of cortico-subcortical loops involving the basal-ganglia may lead to specific deficits in fact retrieval. However, no verbal deficit, as assumed in the triple code model and reported in similar cases, could be observed. The present findings further add to current knowledge on numerical processing, showing how fronto-executive dysfunction may disrupt conceptual understanding of arithmetic. This study shows that not only parietal lesions may lead to severe deficits in conceptual understanding, but that basal ganglia lesions leading to frontal dysfunction may have a devastating effect.

Basal Ganglia Diseases↗
PubMed2004

Linguistic deficits following left selective amygdalohippocampectomy: a prospective study.

Language deficits in 10 patients with medically intractable left-sided temporal lobe epilepsy prior to and following selective amygdalohippocampectomy are described. Preoperatively, a pattern of minor linguistic deficits was observed in three patients; isolated minor naming deficits were detectable in one additional patient. Three months after surgery, six patients' linguistic functions were unchanged, whereas in four patients, a significant decline in linguistic functions could be observed. All four patients revealed a very similar language syndrome characterized by reduced language comprehension and fluency, well-articulated speech, frequent word-finding difficulties, circumlocutions, and semantic paraphasias in the absence of any phonological disorder. These deficits remained stable during the 12-month follow-up period. However, magnetic resonance imaging did not show any neocortical lesions outside the resection area. Possible explanations for these findings include neuronal cell loss and deafferentiation in cortical areas, disruption of the basal temporal language area pathways, reorganization of the language network in chronic temporal lobe epilepsy, and neocortical lesions due to the surgical intervention. Furthermore, correlations between linguistic and demographic data for our patients suggest that patients older at epilepsy onset are at greater risk for developing postoperative language deficits.

Adult↗
PubMed2004

Hermann Zingerle's "Impaired perception of the own body due to organic brain disorders". 1913. An introductory comment, and an abridged translation.

In the late 1970's Edoardo Bisiach and his coworkers provided definitive evidence that spatial unilateral neglect involves a disorder of the internal representation of extra-personal space. A few years later Bisiach and Berti (1987) revived the so far neglected contribution of an Austrian neurologist, Hermann Zingerle (1913). Ninety years ago Zingerle had described the symptom-complex of two right-brain-damaged patients, who showed left hemisomatoagnosia, unawareness of left hemiplegia, and left motor neglect. In addition to the detailed case reports, Zingerle had put forward a unitary interpretation of these deficits in terms of a disordered representation of one side of the body (dyschiria). A unitary representational account of these unilateral impairments was conspicuously absent in the contemporary neurological literature (Anton, Pick, Babinski), and attracted Bisiach's interest. An abridged translation of Zingerle's paper is provided. The clinical case reports and Zingerle's conclusions are discussed, with reference both to Bisiach's views, and to present knowledge of unilateral spatial neglect.

Body Image↗
PubMed2004

Linguistic and neuropsychological deficits in crossed conduction aphasia. Report of three cases.

This study describes the linguistic and neuropsychological findings in three right-handed patients with crossed conduction aphasia. Despite the location of the lesion in the right hemisphere, all patients displayed a combination of linguistic deficits typically found in conduction aphasia following analogous damage to the left hemisphere. Associated cognitive deficits varied across the three patients. In addition, all cases showed deficits classically attributed to non-dominant hemisphere damage (visuoperceptual deficits and reduced figural memory). As a result, lesion-behaviour relationships in our study sample indicate both dominant and non-dominant qualities of the right hemisphere.

Adult↗
PubMed2004

Genital automatisms: a video-EEG study in patients with medically refractory seizures.

PURPOSE: Genital automatisms (GAs) are rare clinical phenomena during or after epileptic seizures. They are defined as repeated fondling, grabbing, or scratching of the genitals. The anatomic correlates of GAs have been discussed controversially. The aim of this investigation was to assess the localizing and lateralizing value of GAs. METHODS: The authors studied 207 consecutive patients with intractable seizures referred to a University Hospital for presurgical evaluation between 1998 and 2002: 135 had temporal lobe epilepsy (TLE); 23, frontal lobe epilepsy (FLE); 29, generalized epilepsies (GEs); and 20 had extratemporal or multifocal epilepsy. RESULTS: Twenty-three (11%) of 207 patients showed GAs in 42 (3%) of 1,299 seizures. GAs occurred significantly more often in men (17 of 93, 18%) than in women (six of 114, 5%; p = 0.0037). Twenty-one (16%) of 135 patients with TLE performed GAs, one (4%) of 23 with FLE and one (3%) of 29 with GE. GAs were associated with unilateral hand automatisms in 16 (70%) of 23 and with periictal urinary urge in five (22%) of 23. All patients had amnesia for the performance of GAs. CONCLUSIONS: GAs appear in the ictal or postictal period with impaired consciousness. Men exhibit GAs significantly more often than do women. GAs do not localize or lateralize per se, but may localize seizure onset in the presence of periictal urinary urge or unilateral hand automatisms. They show a tendency to occur more often in TLE.

Adolescent↗
PubMed2003

Acute conduction aphasia: an analysis of 20 cases.

In this study, the linguistic performance of 20 patients with acute conduction aphasia (CA) is described. CA presented as a relatively homogeneous aphasic syndrome characterized by a severe impairment of repetition and fluent expressive language functions with frequent phonemic paraphasias, repetitive self-corrections, word-finding difficulties, and paraphrasing. Language comprehension as assessed by tests of auditory and reading comprehension was only mildly impaired, whereas most patients performed poorly on the Token Test. Verbal-auditory short-term memory was reduced in all patients except one and seems to play a role in associated cognitive deficits, such as impaired syntactic comprehension or reduced mental arithmetics. A follow-up examination of 12 patients showed that CA often resulted in a chronic language deficit. Lesion locations were the posterior temporal and inferior parietal lobe.

Acute Disease↗
PubMed2003

The thalamus and basal ganglia: What is exactly where? A reply to 'Neuropsychological consequences of right thalamic injury: case study and review,' MJ Summers, Brain and Cognition 50 (2002).

The present paper re-analyzes anatomical and clinical data of a previous case report (Summer, 2002). In this case study, a patient with severe neuropsychological and behavioral impairments is described and it is claimed that these impairments are causally linked to an right thalamic lesion. A simple method how to perform a lesion analysis is introduced which shows that PD's lesion was a striatocapsular hematoma, and not a thalamic bleeding. The results of this anatomical re-analysis challenge the original behavioral-lesion hypothesis and emphasize the importance to provide appropriate data on brain lesions and clinical findings in neuropsychological case reports.

Basal Ganglia↗
PubMed2003

Dichotic listening performance and frontal lobe function.

In the present paper we report on speech perception in left (n=16) and right (n=10) frontal lobe nonaphasic patients compared with healthy controls (n=26). The patients were inpatients of the University Clinic of Neurology, Innsbruck, Austria, who participated in a prospective neuropsychological study dealing with several aspects of lateralized functioning. The patients were tested with dichotic presentations of consonant-vowel syllables, which allows for specific probing of speech perception in the left and right hemisphere, respectively. The task was to report which syllable they heard best on each trial, emphasizing single answers on each trial. There were 36 dichotic trials with pairs of CV syllables made up of the six stop consonants /p/, /t/, /k/, /b/, /d/, /g/, all paired with the vowel /a/. There were always two different syllables presented on each trial, one in each ear. The results showed significant differences between the left and right lesioned patients in their performance on the dichotic listening test. While the right lesioned patients and the control subjects had a normal and expected right ear advantage, the left lesioned patients performed almost at random with regard to the right and left ear stimulus. The right lesioned patients and the control group showed a right ear advantage of the same magnitude, although the overall performance was somewhat impaired in the right lesioned group compared to the healthy control group. The left lesioned patients showed no ear advantage at all, and particularly their right ear scores were impaired compared to both the control group and the right lesioned patient group. The results are discussed in terms of the role played by the left frontal cortex in speech perception and language asymmetry.

Adult↗
PubMed2003

Medial temporal lobe activation during semantic language processing: fMRI findings in healthy left- and right-handers.

Medial temporal lobe (MTL) areas are well known to serve episodic memory functions; their contribution to semantic memory has been occasionally noticed but not studied in detail. In the present fMRI study, 35 right-handed and 35 left-handed healthy subjects performed a semantic decision paradigm during which subjects heard spoken concrete nouns designating objects and had to decide on whether these objects were available in the supermarket and cost lest then a certain amount of money. The control paradigm consisted of sequences of low and high tones where subjects had to decide whether a sequence contained two high tones. The resulting contrast activation of semantic decision versus tone decision involved neocortical temporal, parietal, and prefrontal areas. Additional significant, bilateral activations in the MTL, the hippocampal formation, and adjacent areas were found. The exact incidence and location of activation was studied in a single-subject analysis for all 70 subjects. At the chosen threshold of P<0.001, 94% of subjects showed activations in the MTL and inferior temporal lobe (ITL). Activations were found along the longitudinal axis of the MTL, including the hippocampal formation and the parahippocampal gyrus. In the ITL, parts of the fusiform and lingual gyri were activated. Activations were similar in right- and left-handers. We conclude from this study that the MTL and parts of the ITL can be added to the areas activated by semantic verbal memory processing.

Acoustic Stimulation↗
PubMed2003

Everyday numerical abilities in Alzheimer's disease.

The present study investigated everyday numerical abilities in a group of 21 patients affected by mild to moderate dementia of Alzheimer's type (DAT). Though patients did not differ from a control group in standard laboratory tests tapping transcoding, number comparison, simple calculation, and estimation, they showed significant difficulties in numerical tasks embedded in an everyday context, such as handling money, a bus schedule, or a television program. Patients' difficulties were attributed to those multiple cognitive demands which are inherent to real situations as compared to well-structured abstract paper-and-pencil tasks. Overall, the study suggests that the examination of numerical abilities in DAT patients should go beyond abstract paper-and-pencil tasks which can only partially reflect the actual numerical skills in DAT and should therefore include also tasks simulating everyday life situations. Assessment of everyday numerical skills may be crucial in planning adequate support for patients, for example in handling money, but also in designing targeted training programs.

Activities of Daily Living↗
PubMed2003

Basal ganglia lesions and the theory of fronto-subcortical loops: neuropsychological findings in two patients with left caudate lesions.

Basal ganglia lesions have a high prevalence for associated behavioural impairments. However, the exact pattern of cognitive impairments and its relationship to individual basal ganglia lesion have rarely been investigated by means of a detailed neuropsychological and lesion study. Furthermore, different mechanisms have been proposed as relevant for the observed cognitive deficits; among these, the hypothesis of fronto-subcortical loops (Alexander et al., 1986) has made predictions regarding the relationship between the damage of particular striato-frontal circuits and the resulting behavioural impairment which await clinical confirmation. We present a study of two subjects who suffered a MRI-documented focal left basal ganglia hematoma. The two patients differed in their lesions; in one patient (PJ) large parts of the caudate nucleus were destroyed whereas in the other (AS) mainly the pallidum and putamen were lesioned and the caudate suffered only minor damage. In the acute phase, the behavioural and neuropsychological abnormalities were similar in both cases and included mainly abulia, an impairment of executive and attentional functions, and a severe amnestic syndrome. After several months many functions were restored in AS, whereas PJ's abilities remained largely defective. Based on these data and on previous case studies several conclusions are drawn. Left caudate lesions induce marked and long-lasting behavioural and neuropsychological impairments comprising predominantly drive, executive control, attention, and memory. The extent of lesion in the head of the caudate nucleus is the critical factor regarding the severity and the outcome of the syndrome, whereas damage to the putamen and pallidum is less crucial for cognitive functions. A subset of behavioural alterations, among them abulia, attentional and frontal-executive dysfunctions, can well be attributed to lesions of the anterior cingulate circuit and the dorsolateral-frontal circuit at the basal ganglia level. Other impairments, most importantly the prominent amnestic syndrome, are more difficult to interpret on the grounds of this hypothesis and may be related to other pathomechanisms.

Basal Ganglia↗
PubMed2002

Persistent cognitive deficits associated with lithium intoxication: a neuropsychological case description.

We present the case of a 51-year-old patient with an acute lithium intoxication associated with several cognitive deficits. During the acute phase of intoxication the patient displayed general psychomotor slowing, dysarthric speech, mood changes, and incoherent discourse. Neuropsychological assessment revealed ideomotor apraxia, profound deficits of visuospatial processing, an impairment of memory and of frontal-executive functions. Other cognitive abilities, such as orientation, spontaneous speech, comprehension, naming, reading, writing, and working memory remained intact. An electroencephalogram revealed diffuse slowing with rhythmic trains, whereas MRI showed no cerebral abnormality. Follow-up examinations at 4 and 14 weeks with lithium levels in the normal range showed substantial recovery of memory abilities and executive functions, whereas praxis and visuoperceptual functions remained impaired, despite the fact that lithium was immediately withdrawn after the intoxication became manifest. We conclude that lithium intoxication may be associated with variable behavioural and cognitive impairments, some of them potentially persistent. Different from other case studies our findings suggest that lithium intoxication may cause a combined, multifocal functional impairment of subcortical and cortical neural mechanisms in both hemispheres.

Antimanic Agents↗