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Probabilistic learning and reversal deficits in patients with Parkinson's disease or frontal or temporal lobe lesions: possible adverse effects of dopaminergic medication.

Three groups of patients with Parkinson's disease (PD) - mild, unmedicated (UPD), mild, medicated (MPD) and severe, medicated (SPD) - and patients with lesions of the frontal lobe (FLL) or temporal lobe (TLL) were compared with matched controls on the learning and reversal of probabilistic and two-pair concurrent colour discriminations. Both of the cortical lesion groups showed reversal deficits, with no increase in perseverative responding. The UPD group, although impaired on a spatial recognition task, showed intact discrimination learning and reversal; the MPD and SPD patients showed non-perseverative reversal impairments on both reversal tasks. Two hypotheses - based on disease severity and possible deleterious effects of medication - are offered to explain the reversal impairments of the PD patients and the results are discussed in terms of the role of dopamine in reward-based learning.

Adult↗

Quantitative temporal lobe differences: autism distinguished from controls using classification and regression tree analysis.

The temporal lobe is thought to be abnormal in autism, yet standard volumetric analyses are often unrevealing when age, sex, IQ, and head size are controlled. Quantification of temporal lobe structures were obtained in male subjects with autism and controls, where subjects with head circumference (HC) defined macrocephaly were excluded, so that volume differences were not just related to the higher prevalence of macrocephaly in autism. Various statistical methods were applied to the analysis including a classification and regression tree (CART) method, a non-parametric technique that helps define patterns of relationships that may be meaningful in distinguishing temporal lobe differences between subjects with autism and age and IQ matched controls. Subjects with autism were also compared to a separate control group with reading disorder (RD), with the prediction that the temporal lobe morphometric analysis of the reading disorder controls would be more similar to that of the autism group. The CART method yielded a high specificity in classifying autism subjects from controls based on the relationship between the volume of the left fusiform gyrus (LFG) gray and white matter, the right temporal stem (RTS) and the right inferior temporal gyrus gray matter (RITG-GM). Reading disordered individuals were more similar to subjects with autism. Simple size differences did not distinguish the groups. These findings demonstrate different relationships within temporal lobe structures that distinguish subjects with autism from controls. Results are discussed in terms of pathological connectivity within the temporal lobe as it relates to autism.

Adolescent↗

The temporal lobes, reversed asymmetry and the genetics of schizophrenia.

Mechanisms determining temporal lobe structural asymmetries may be involved in the pathogenesis of schizophrenia. To investigate the temporal lobes in familial schizophrenia, computed tomographic scans were obtained from 51 subjects (seven families). Enlargement of sylvian fissures and temporal lobe sulcal spaces was observed in family members with schizophrenia. The posterior one-third of the sylvian fissure was larger on the left side in subjects with schizophrenia, and larger on the right side in unaffected individuals. This disturbed pattern of posterior sylvian fissure asymmetry suggests that adjacent language regions may be affected in schizophrenia. An intermediate degree of disturbance in subjects who had schizophrenia-related illnesses or were obligate carriers suggests that genetic factors may be important determinants of temporal lobe asymmetries in familial schizophrenia.

Adult↗

Ipsilateral thalamic hypoperfusion on interictal SPECT in temporal lobe epilepsy.

UNLABELLED: Interictal brain SPECT is useful for the localization of a seizure focus. Concomitant hypoperfusion of the ipsilateral thalamus on interictal SPECT has been noted for temporal lobe epilepsy. In this study, we aimed to evaluate the prevalence of thalamic hypoperfusion ipsilateral to temporal hypoperfusion (ipsilateral thalamic hypoperfusion) and to assess the usefulness of this finding for the lateralization of epileptic foci on interictal SPECT for temporal lobe epilepsy patients. METHODS: Forty-six patients with refractory temporal lobe epilepsy underwent interictal brain SPECT after intravenous injection of 555-740 MBq of 99mTc-ECD. Perfusion impairments in the brain, especially the temporal lobe and thalamus, were evaluated. The localization of seizure foci was determined in conjunction with scalp, ictal and cortical electroencephalography, MRI and clinical outcomes. Ictal SPECT was performed for 5 of the 12 patients. RESULTS: Concomitant decreased perfusion in both the temporal lobe and the ipsilateral thalamus was observed for 12 (26%) of 46 temporal lobe epilepsy patients on interictal brain SPECT. Seven patients showed hypoperfusion in the left temporal lobe and ipsilateral thalamus. Five patients showed hypoperfusion in the right temporal lobe and ipsilateral thalamus. In addition, hypoperfusion in the ipsilateral basal ganglia (ten patients) or contralateral cerebellum (four patients) was observed. CONCLUSION: Ipsilateral thalamic hypoperfusion is not uncommon in temporal lobe epilepsy. The exact mechanism causing ipsilateral thalamic hypoperfusion is uncertain; however, corticothalamic diaschisis may be an important factor. This finding may aid in the lateralization of seizure foci on interictal brain SPECT.

Adolescent↗

Proton magnetic resonance spectroscopy of temporal lobe white matter in patients with histologically proven hippocampal sclerosis.

The purpose of this study was to assess temporal lobe white matter changes accompanying hippocampal sclerosis on magnetic resonance (MR) imaging using single-voxel 1H MR spectroscopy and to strengthen the hypothesis that these white matter changes are caused by myelin alterations. In 11 patients with histologically proven hippocampal sclerosis, preoperative coronal fluid-attenuated inversion recovery images were visually assessed by two experienced neuroradiologists for hippocampal signal increase and size decrease, atrophy of collateral white matter, and temporal lobe gray/white matter demarcation loss. Single-voxel 1H MR spectroscopy of the white matter of each anterior temporal lobe was also performed, excluding the amygdala and hippocampus. The N-acetyl-aspartate (NAA)/choline and NAA/creatine ratios were calculated. In 12 healthy volunteers both temporal lobes were spectroscopically examined. In all patients the excised hippocampi were histologically assessed for the presence of sclerosis, and the excised neocortical temporal lobes were examined for gray and white matter abnormalities. MRI abnormalities were found on the right in six patients, on the left in four, and one scan was normal. Hippocampal signal increase was seen in nine patients, hippocampal size decrease in ten, atrophy of collateral white matter in nine, and gray/white matter demarcation loss in six. A significant decrease in the NAA/choline ratio was found in temporal lobe white matter ipsilateral to the pathologic hippocampus (symptomatic side), compared with the contralateral, asymptomatic side (P < 0.01), and also compared with controls (P < 0.001). The ipsilateral NAA/creatine ratio was also significantly decreased (P < 0.05) compared with the contralateral side and the control subjects (P < 0.001). Histological examination showed hippocampal sclerosis to a different degree in all patients. Neither gliosis nor cortical dysplasia was found in the ipsilateral, symptomatic temporal lobe. Significant decrease in the mean of NAA/choline ratios is found in temporal lobe white matter of patients with histologically confirmed hippocampal sclerosis. As this indicates neuronal loss or dysfunction, the number of axons may be reduced, with associated decrease in myelin density.

Adult↗

Voxel-based morphometry of unilateral temporal lobe epilepsy reveals abnormalities in cerebral white matter.

Voxel-based morphometric (VBM) investigations of temporal lobe epilepsy have focused on the presence and distribution of gray matter abnormalities. VBM studies to date have identified the expected abnormalities in hippocampus and extrahippocampal temporal lobe, as well as more diffuse abnormalities in the thalamus, cerebellum, and extratemporal neocortical areas. To date, there has not been a comprehensive VBM investigation of cerebral white matter in nonlesional temporal lobe epilepsy. This study examined 25 lateralized temporal lobe epilepsy patients (13 left, 12 right) and 62 healthy controls in regard to both temporal and extratemporal lobe gray and white matter. Consistent with prior reports, gray matter abnormalities were evident in ipsilateral hippocampus and ipsilateral thalamus. Temporal and extratemporal white matter was affected ipsilateral to the side of seizure onset, in both left and right temporal lobe epilepsy groups. These findings indicate that chronic temporal lobe epilepsy is associated not only with abnormalities in gray matter, but also with concomitant abnormalities in cerebral white matter regions that may affect connectivity both within and between the cerebral hemispheres.

Adolescent↗

Late temporal lobe necrosis in patients with nasopharyngeal carcinoma: evaluation with combined multi-section diffusion weighted and perfusion weighted MR imaging.

Late temporal lobe necrosis is a well-known and serious complication in patients with nasopharyngeal carcinoma (NPC) following radiotherapy. Owing to the close proximity to the skull base, the medial temporal lobes are inevitably included in the target volume of irradiation. Patients with NPC provide a unique opportunity in study of delay radiation effect in normal human brain. The objective of this study was to evaluate late temporal lobe radiation injury by combined multi-section diffusion weighted and perfusion weighted MR imaging. We prospectively studied 16 patients with typical clinical symptoms of late temporal lobe necrosis or other abnormalities in the temporal lobes incidentally detected by conventional MR imaging. All patients had a previous history of radiotherapy for histologically proven NPC. Conventional T1- and T2-weighted images, fast gradient echo with echo-planar diffusion-weighted and perfusion-weighted MR imaging were performed. Apparent diffusion coefficient (ADC) map and relative cerebral blood volume (rCBV) map were computed via commercially available software. MR diffusion and perfusion images were then analyzed and graded by two independent observers with focusing on the diffusion and perfusion mismatch. The temporal lobe lesions displayed marked high diffusion on the ADC map. The rCBV map also revealed marked hypoperfusion in these temporal lobe lesions in all patients. The areas of abnormality on the rCBV map were significantly larger than the lesions on the ADC map in 14 patients (observer 1) and 13 patients (observer 2). Since late temporal lobe necrosis is probably caused by damage of the endothelium of vessels and ischemia, perfusion and diffusion mismatch might imply injured tissue but potentially salvageable brain tissue. A mismatch may be potentially used to predict the response to treatment in-patients with late temporal lobe necrosis.

Adult↗

Memory and intelligence in lateralized temporal lobe epilepsy and schizophrenia.

Recent neuroimaging studies of patients with schizophrenia have suggested structural and functional abnormalities of mesial temporal lobe structures. We compared the intelligence and memory test performance of 70 patients with schizophrenia and 72 patients with focal, lateralized temporal lobe epilepsy (30 left, 42 right temporal lobe) in order to examine the adequacy of a temporal lobe model of schizophrenic cognitive deficits. The groups did not differ in age, education, or Full Scale IQ. The right temporal lobe group had better overall memory performance than either the left temporal or schizophrenic patients. Unlike the schizophrenic patients, the memory impairment of the left temporal group was most evident with verbal materials and was amplified by delayed testing. Both epilepsy groups had better visual memory than the schizophrenic group. The clear differences in performance pattern between groups suggests that lateralized temporal lobe dysfunction does not by itself provide an adequate model of schizophrenic cognitive impairment.

Adult↗

Comparison of localizing values of various diagnostic tests in non-lesional medial temporal lobe epilepsy.

Though the surgical treatment for medial temporal lobe epilepsy yields a high success rate, more studies are needed in order to determine the most efficacious pre-operative algorithm. The authors studied the relationship between surgical outcome and the localization results of various pre-operative diagnostic tests to assess the predictive value. Seventy-one consecutive patients who had undergone anterior temporal lobectomy with amygdalohippocampectomy with the diagnosis of non-lesional medial temporal lobe epilepsy, who had been followed up more than 24 months, were analyzed retrospectively. Electroencephalogy (EEG), magnetic resonance imaging (MRI), proton emission tomography (PET), single photon emission computed tomography (SPECT), the Wada test, and neuropsychological testing were analyzed. There was no diagnostic test that was found to have a statistically significant relationship between Engel Class I outcome and localization results (P & 0.05). SPECT, neuropsychological testing, and the Wada test all had less predictive values (P < 0.01). EEG and PET had comparable predictive values for Engel Class I with MRI (P & 0.05). No single diagnostic test alone is sufficient to make a diagnosis of non-lesional medial temporal lobe epilepsy. MRI, EEG and PET had comparable predictive values for Engel Class I. SPECT, neuropsychological testing, and the Wada test had less predictive values.

Adolescent↗

On the psychopathology of unilateral temporal lobe epilepsy.

Personality adjustment of patients with unilateral temporal lobe epilepsy (TLE) was investigated in the light of special characteristics of the epilepsy process, psychosocial stressors, and the cognitive status of the patients. Thirty-seven patients with medically intractable unilateral temporal lobe epilepsy (16-55 years of age; 20 right temporal and 17 left temporal foci) were examined with standardized personality inventories (FPI, STAI, IPC, TSK) supplemented by a rating scale evaluated by the neuropsychologist (GEWLE). Patients with left temporal lobe epilepsy were characterized by increased emotional dependency, less externally judged composedness, increased depressive drive and mood, increased nervousness, increased search for information and exchange of disease experience, and greater tendency to persevere (P < 0.05). Cognitive status and psychosocial status did not significantly differ. The evaluation of personality adjustment contributes to the lateralization of the epileptogenic focus and reveals interesting patterns in the preoperative diagnostic puzzle, and in addition provides a strategy to individualize psychotherapeutic strategies.

Adult↗

Regional lumped constant differences and asymmetry in fluorine-18-FDG uptake in temporal lobe epilepsy.

UNLABELLED: To date, there has been no satisfactory explanation for the observation that interictal uptake of the glucose analog [18F]fluorodeoxyglucose (FDG) is consistently reduced in the temporal lobe ipsilateral to the seizure focus in patients with temporal lobe epilepsy. We examined the hypothesis that regional differences in tracer uptake in temporal lobe epilepsy reflect regional differences in the lumped constant (lambda). METHODS: In 9 control subjects and 10 patients with temporal lobe epilepsy, we obtained regional estimates of lambda by expressing lambda in terms of transfer coefficients for FDG and parameters which are likely to remain constant throughout both the brain and under different functional states. RESULTS: In the patients, lambda was lower in the temporal lobe ipsilateral to the epileptic focus (0.53 +/- 0.06; p < 0.005) than in the contralateral temporal lobe (0.56 +/- 0.06). Interside differences in lambda were highly correlated with asymmetry in tracer uptake. Furthermore, the use of regional estimates of lambda reduced the asymmetry in estimated rCMRglc in patients with temporal lobe epilepsy but not in controls. CONCLUSION: In these patients, a change in tracer uptake may not indicate a change in glucose consumption of corresponding magnitude, raising the possibility that in at least some patients with temporal lobe epilepsy, the term hypometabolism does not accurately describe reductions in tracer uptake.

Adult↗

Association of ipsilateral motor automatisms and contralateral dystonic posturing: a clinical feature differentiating medial from neocortical temporal lobe epilepsy.

BACKGROUND: Clinical features that may help to differentiate medial temporal lobe epilepsy (MTLE) from neocortical temporal lobe epilepsy (NTLE) are lacking. OBJECTIVE: To investigate the localizing and lateralizing value of the association of ipsilateral motor automatisms and contralateral dystonic posturing in patients with medically refractory temporal lobe epilepsy. PATIENTS AND METHODS: Videotapes of 60 patients with well-defined MTLE, NTLE, or both were reviewed to assess the presence and the localizing value of unilateral dystonic posturing associated with motor automatisms. RESULTS: Twenty-eight of the 60 patients exhibited unilateral dystonic posturing. This sign was observed in patients with MTLE and NTLE. It was mostly contralateral to the seizure focus in patients with MTLE and exclusively ipsilateral in patients with NTLE. Unilateral motor automatisms occurred in 26 of the 60 patients with MTLE or NTLE. It was predominantly ipsilateral to the seizure focus in patients with MTLE and exclusively contralateral in patients with NTLE. The association of ipsilateral motor automatisms and contralateral dystonic posturing was found in 14 patients with MTLE but in none of the patients with NTLE. Two patients who had medial and neocortical seizure onset also exhibited this clinical feature. This association was not significantly correlated with the postoperative outcome in patients with MTLE. CONCLUSIONS: The association of ipsilateral motor automatisms and contralateral dystonic posturing may help to differentiate MTLE from NTLE with a reliable lateralizing value. This clinical association may reflect a specific pattern in the spread of the ictal discharge.

Adult↗

Temporal hypometabolism at the onset of cryptogenic temporal lobe epilepsy.

Most patients with intractable temporal lobe epilepsy (TLE) exhibit temporal glucose hypometabolism. The reasons for the development of this abnormality are as yet unclear. The current notion is that an initial injury causes seizures, which in turn give rise to hypometabolism. The aim of this study was to assess whether temporal reductions in glucose metabolism in non-lesional TLE are the result of repeated seizures or whether hypometabolism represents an initial disturbance at the onset of disease. Glucose consumption was assessed with fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) in 62 patients with cryptogenic non-refractory TLE in different stages of disease. Twelve subjects without neurological illness served as controls. Patients with onset of epilepsy at least 3 years prior to the PET scan were defined as having chronic TLE. Using this criterion, the whole patient cohort included 27 patients with de novo TLE and 35 patients with chronic TLE. The groups were matched for age and sex. The appearance of high-resolution magnetic resonance images of the brain was unremarkable in all patients. In the total cohort, number, duration and frequency of seizures had a significant relation to the magnitude of hypometabolism. Temporal hypometabolism was exhibited by 26 of the 62 patients (42%), including 8 out of 27 (30%) with newly diagnosed TLE and 18 out of 35 (51%) with chronic TLE. The disturbances were more extensive and more severe in patients with chronic TLE. It is concluded that temporal hypometabolism may already be present at the onset of TLE, but is less frequent and less severe in newly diagnosed than in chronic TLE. The metabolic disturbance correlates with the number of seizures. These findings suggest that an initial dysfunction is present in a considerable number of patients and that hypometabolism is worsened by continuing epileptic activity.

Adolescent↗

Cortical and hippocampal volume deficits in temporal lobe epilepsy.

PURPOSE: To use quantitative magnetic resonance imaging (MRI) methods to examine the extent of volume abnormalities in the hippocampus and in extrahippocampal brain regions in localization-related epilepsy of temporal lobe origin (TLE). METHODS: Hippocampal, temporal lobe, and extratemporal lobe volumes were examined with 3-mm spin-echo coronal MRI scans in patients with unilateral TLE who were candidates for temporal lobe resection. Measures were adjusted for normal variation due to intracranial volume and age based on 72 healthy male controls. Group differences between 14 male TLE [7 left TLE (LTLE), 7 right TLE (RTLE)] patients and a subset of 49 age range-matched controls were examined with analysis of variance (ANOVA). RESULTS: As compared with controls, patients with TLE had smaller temporal lobe and frontoparietal region gray matter volumes, bilaterally, smaller temporal lobe white matter volumes bilaterally, and larger ventricular volumes. In contrast to these bilateral tissue volume deficits, hippocampal volume deficits in TLE were ipsilateral to the epileptogenic temporal lobe. CONCLUSIONS: Extrahippocampal volume abnormalities were bilateral and occurred in both temporal and extra-temporal cortical regions in TLE, whereas hippocampal deficits were related to the side of the epileptogenic focus. These data suggest that brain abnormalities in TLE are not limited to the epileptogenic region.

Adolescent↗

Association of temporal lobe epilepsy and obsessive-compulsive disorder in a patient successfully treated with right temporal lobectomy.

A patient who developed obsessive-compulsive symptoms shortly after the onset of temporal lobe epilepsy exhibited almost complete remission after being rendered seizure-free by surgical intervention. These data support the hypothesis that temporal lobe epilepsy and obsessive-compulsive disorder (OCD) share at least some pathophysiological components. The diagnosis of temporal lobe epilepsy was made by ictal video/EEG recordings, concordant with the presence of a lesion in the posterior region of the temporobasal neocortex. The OCD was diagnosed on the basis of DSM-IV-TR criteria through a clinical interview while the intensity of the OCD symptoms was assessed with the Yape-Brown Obsessive-Compulsive Scale. Surgical intervention consisted of a complete lesionectomy in association with a right temporal lobectomy including both lateral and mesial structures. The patient had follow-up visits after 6 months and 1 year. At both times, the patient remained free of seizures and reported a progressive reduction in OCD symptomatology.

Adult↗

Electrical source analysis of auditory ERPs in medial temporal lobe amnestic syndrome.

Auditory event-related potential (ERP) components have been anatomically linked to temporal lobe structures and functionally related to attentional and memory processes. We recorded auditory ERPs using an "oddball" paradigm from two patients with amnestic syndromes secondary to medial temporal lobe encephalitic infections. The oddball paradigm elicits the exogenous N1 and P2 components, and the endogenous N2 and P3 components. Electrical source analysis was used to test for alterations in source strength and orientation in these patients compared to control subjects. Symmetric dipoles placed in the temporal lobe region were used to measure ERP component activity. In the patient with a lesion confined to the left, medial temporal lobe, including the posterior hippocampus, dipole orientation was displaced anteriorally. In the patient with lesions to the anterior medial temporal lobe, temporal poles, and orbital frontal cortex, the negative components of the ERP (N1 and N2) were reduced in the right hemisphere, accompanied by disturbed orientation. These findings are consistent with other evidence that the different components of the auditory ERP can be dissociated on the basis of lesion effects, and that the antero-posterior extent of encephalitic lesions may play an important role in modulating ERP abnormalities.

Acoustic Stimulation↗

Memory fMRI lateralizes temporal lobe epilepsy.

BACKGROUND: The assessment of mesial temporal lobe (MTL) function is important for the diagnosis and treatment of temporal lobe epilepsy (TLE) and other brain diseases. Declarative memory depends on the integrity of the MTL region. OBJECTIVE: To investigate hemispheric asymmetries of MTL activity in patients with symptomatic TLE. METHODS: With use of blood oxygenation level-dependent fMRI, hemispheric asymmetries in MTL activation of 30 individual patients with refractory symptomatic TLE and 17 healthy control subjects were studied. Activation was induced by a task employing mental navigation and recall of landmarks based on the retrieval of individually familiar visuospatial knowledge. RESULTS: The study demonstrated that the memory task used reliably activated MTL structures in individual control subjects and patients with refractory TLE including children, older subjects, and patients with low formal IQ. Interhemispheric differences in MTL activation lateralized the side of seizure onset in 90% of patients with symptomatic unilateral TLE. In contrast, healthy control subjects did not show a systematic asymmetry of MTL activation. Correlations between MTL activation and neuropsychological measures suggest that the fMRI-detectable MTL changes were specifically related to memory rather than to memory-independent visuospatial abilities. CONCLUSION: fMRI of memory-induced MTL activation lateralizes the side of seizure onset in patients with refractory symptomatic TLE and may provide complementary information for presurgical evaluation.

Adolescent↗

Clinical and genetic heterogeneity in familial temporal lobe epilepsy.

PURPOSE: Familial forms of temporal lobe epilepsy have been described recently. A locus on ch 10q has been linked to partial epilepsy with auditory symptoms. We investigated the proportion of families segregating temporal lobe epilepsy (TLE) linked to ch 10q and sought to establish genotype-phenotype correlations. METHODS: We studied 15 unrelated families segregating TLE. A total of 153 individuals, including 79 patients, were analyzed in this study. Family members were genotyped for four polymorphic dinucleotide repeat markers: D10S185, D10S574, D10S577, and D10S192, which flank the 15-cM candidate interval on ch 10q. Two-point lod scores were calculated for each family separately. RESULTS: Fourteen of our families had ictal semiology of mesial temporal onset of seizures and magnetic resonance imaging (MRI) abnormalities in the mesial structures; only one family, with seven affected individuals, reported auditory symptoms and had normal MRIs. Pedigree analysis showed an autosomal dominant transmission with 0.75 penetrance. Only two families had informative lod scores. A large family, with 22 affected individuals segregating mesial TLE, had negative lod scores for all four markers genotyped. The lod scores were significantly negative (less than -2.00) up to 0.05 for D10S185, 0.10 for D10S574, 0.25 for D10S577, and 0.15 for D10S192. The single family with auditory symptoms had positive lod scores for all markers genotyped, with a Z max of 1.52 at 0.0 for D10S574. CONCLUSIONS: We identified two different clinical groups of families segregating TLE. Most families identified in this study had mesial TLE. Only one single family segregating lateral TLE was found. We significantly excluded linkage between familial mesial TLE and the locus on ch 10q. In addition, we showed evidence for linkage between one family with lateral TLE and markers on ch 10q. This is strong evidence for clinical and genetic heterogeneity among familial forms of TLE.

Chromosome Segregation↗