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Quantitative MRI of the temporal lobe, amygdala, and hippocampus in normal human development: ages 4-18 years.

The volume of the temporal lobe, superior temporal gyrus, amygdala, and hippocampus was quantified from magnetic images of the brains of 99 healthy children and adolescents aged 4-18 years. Variability in volume was high for all structures examined. When adjusted for a 9% larger total cerebral volume in males, there were no significant volume differences between sexes. However, sex-specific maturational changes were noted in the volumes of medial temporal structures, with the left amygdala increasing significantly only in males and with the right hippocampus increasing significantly only in females. Right-greater-than-left laterality effects were found for temporal lobe, superior temporal gyrus, amygdala, and hippocampal volumes. These results are consistent with previous preclinical and human studies that have indicated hormonal responsivity of these structures and extend quantitative morphologic findings from the adult literature. In addition to highlighting the need for large samples and sex-matched controls in pediatric neuroimaging studies, the information from this understudied age group may be of use in evaluating developmental hypotheses of neuropsychiatric disorders.

Adolescent↗

Temporal lobe rating scale: application to Alzheimer's disease and frontotemporal dementia.

OBJECTIVES: Temporal lobe atrophy as assessed by MRI can be measured in several ways. Volumetric measurements are quantitative but very time consuming and require extensive training to perform, so are not easily transferable to clinical practice. Visual rating scales, by contrast, are quick and widely applicable. Although medial temporal lobe atrophy is well described in Alzheimer's disease (AD), it is uncertain how early these changes can be detected and whether they discriminate AD from other neurodegenerative diseases, most notably frontotemporal dementia (FTD). The objectives were (1) to develop a widely applicable temporal lobe rating scale, and (2) to characterise and quantify the patterns of temporal lobe atrophy in AD versus temporal and frontal variants of FTD. METHODS: The temporal lobe assessments were made using an established hippocampal rating scale extended to incorporate additional temporal regions. This was firstly validated with volumetric analysis and then applied to 30 probable AD, 30 FTD (consisting of 17 temporal variant (semantic dementia) and 13 frontal variant) and 18 control coronal MRI images. RESULTS: Bilateral hippocampal atrophy was found in 50% of the patients with AD. Contrary to expectations, patients with semantic dementia also had hippocampal atrophy, which for the left side exceeded that seen in AD; other regions (temporal pole, parahippocampal gyrus, and lateral temporal lobe), spared in AD, were severely atrophied in this group. The patients with frontal variant FTD occupied an intermediate position and were largely indistinguishable from AD. CONCLUSIONS: Hippocampal atrophy is, therefore, not specific for AD. Semantic dementia can be distinguished from AD, by the presence of severe bilateral atrophy of the temporal pole, parahippocampal and lateral regions. These findings have implications for the differential diagnosis of dementias.

Aged↗

Differential glutamate dehydrogenase (GDH) activity profile in patients with temporal lobe epilepsy.

PURPOSE: Pathophysiologic mechanisms underlying temporal lobe epilepsy (TLE) are still poorly understood. One major hypothesis links alterations in energy metabolism to glutamate excitotoxicity associated with seizures in TLE. The purpose of this study was to determine whether changes in the activities of enzymes critical in energy and neurotransmitter metabolism contributed to the alterations in metabolic status leading to the excitotoxic effects of glutamate. METHODS: Activities of four key enzymes involved in energy metabolism and glutamate cycling in the brain [aspartate aminotransferase (AAT), citrate synthase (CS), glutamate dehydrogenase (GDH), and lactate dehydrogenase (LDH)] were measured in anterolateral temporal neocortical and hippocampal tissues obtained from three different groups of medically intractable epilepsy patients having either mesial, paradoxical, or mass lesion-associated temporal lobe epilepsy (MTLE, PTLE, MaTLE), respectively. RESULTS: We found that GDH activity was significantly decreased in the temporal cortex mainly in the MTLE group. A similar trend was recognized in the hippocampus of the MTLE. In all three patient groups, GDH activity was considerably lower, and AAT and LDH activities were higher in cortex of MTLE as compared with the corresponding activities in hippocampus (p<0.05). In the MTLE cortex and hippocampus, GDH activities were negatively correlated with the duration since the first intractable seizure. CONCLUSIONS: Our results support the hypothesis suggesting major alteration in GDH activity mainly in the MTLE group. It is proposed that significant alterations in the enzyme activities may be contributing to decreased metabolism of glutamate, leading to its accumulation.

Adolescent↗

Reproductive endocrine disorders in women with partial seizures of temporal lobe origin.

Of 50 consecutive women with partial seizures of temporal lobe origin (temporal lobe epilepsy [TLE]) evaluated for reproductive dysfunction, 28 had menstrual problems. Of those, 19 had reproductive endocrine disorders. Polycystic ovarian syndrome and hypogonadotropic hypogonadism occurred significantly more often in women with TLE than in the general female population. Polycystic ovarian syndrome was associated with predominantly left-sided lateralization of interictal epileptic discharges; hypogonadotropic hypogonadism was more commonly found with right-sided discharges. Hyposexuality occurred more often in women with predominantly right-sided interictal epileptic discharges and was associated with low serum luteinizing hormone levels. There are several possible interpretations: epileptic discharges in medial temporal limbic structures may disrupt hypothalamic regulation of pituitary gonadotropin secretion; anovulatory cycles of reproductive endocrine disorders may promote the development of epileptic discharges; and TLE and some associated reproductive endocrine disorders may represent the parallel effects of prenatal factors common to the development of the brain and the reproductive system.

Adult↗

Temporal lobes signs and Jungian dimensions of personality.

Phenomenological experiences that suggest temporal lobe lability were correlated with Jungian personality (Myers-Briggs) indicators. People with frequent temporal lobe indicators were more intuitive than sensing and more perceiving than judging; in the more general population temporal lobe indicators were also weakly associated with feeling rather than thinking. Students who were actively engaged in a drama class also displayed more frequent temporal lobe signs than psychology students. The data are commensurate with the hypothesis that the relationship between belief in psi phenomena, psi experiences, and specific cognitive styles is derived from a temporal lobe lability factor.

Adolescent↗

Temporal lobe epilepsy and aggression.

Research on temporal lobe epilepsy (TLE) and aggression is reviewed in order to learn why it has not contributed more to our understanding of the neural basis of aggression. The research problem can be resolved into two questions: Are temporal lobe epileptics more aggressive? What inferences can be drawn about the factors underlying aggression in TLE? Difficulties in finding suitable operational definitions for TLE and for aggression have, to date, received insufficient attention. In published studies, sample bias and lack of regard for the validity and reliability of behavioral assessments prevent our deciding whether an association exists between interictal aggressive behavior and TLE. Even if this association were demonstrated, one could not draw direct neurobehavioral inferences from it, since a variety of social and psychological, as well as neurophysiological variables could contribute to the association. These would have to be controlled. Methodological refinements could lead to more satisfactory answers to the first question, but the second is considerably more difficult. Some sources of complexity and apparent contradictions in the experimental literature on the neurology of aggression are discussed. They consist of technical problems, the complexity of the neural substrate of aggression and the influence of environmental cues and learning. The combined use of electrophysiological and interview techniques has yielded some interesting results with TLE patients.

Age Factors↗

Somatosensory auras in refractory temporal lobe epilepsy.

PURPOSE: To determine the prevalence, manifestations, lateralizing value, and surgical prognostic value of somatosensory auras (SSAs) in patients with refractory temporal lobe epilepsy (TLE). METHODS: Eighty-one consecutive patients undergoing temporal lobectomy for refractory complex-partial seizures were screened for SSAs. The characteristics of the somatosensory phenomena, occurrence of other aura types, seizure semiology, findings of EEG and imaging studies, temporal lobe neuropathology, and postoperative seizure outcome were determined in each patient with SSAs. RESULTS: Nine (11%) of 81 patients with refractory temporal lobe seizures reported distinct SSAs as part of their habitual seizures. The most common manifestation of SSAs was tingling (eight of nine, 89%), but sensory loss (one of nine, 11%) and pain (one of nine, 11%) also were reported. Five patients had unilateral somatosensory symptoms, and four patients had bilateral somatosensory symptoms. Seizure origin was in the contralateral temporal lobe in four (80%) of five patients with unilateral SSAs, including all patients with unilateral SSAs affecting a limb. Partial temporal lobe resection produced complete seizure remission in all nine (100%) patients 1 year after surgery and in seven (78%) of nine patients 2 years after surgery. CONCLUSIONS: SSAs occur more frequently than previously appreciated in patients with refractory temporal lobe seizures and usually manifest as either unilateral or bilateral tingling. In patients with temporal lobe seizures, unilateral SSAs involving a limb suggest a seizure origin in the contralateral temporal lobe. The surgical outcome of TLE patients with SSAs is favorable. Thus the presence of SSAs should not serve as a deterrent to temporal lobe resection in patients with clearly defined TLE.

Adult↗

Schizotypal personality disorder and MRI abnormalities of temporal lobe gray matter.

BACKGROUND: Structural MRI data indicate schizophrenics have reduced left-sided temporal lobe gray matter volumes, especially in the superior temporal gyrus (STG) and medial temporal lobe. Our data further suggest a specificity to schizophrenia spectrum disorders of STG volume reduction. Interpretation of research studies involving schizophrenics may be complicated by the effects of exposure to neuroleptics and chronic illness. Sharing the same genetic diathesis of schizophrenics, subjects with schizotypal personality disorder (SPD) offer a unique opportunity to evaluate commonalities between schizophrenia and SPD, particularly as SPD subjects are characterized by cognitive and perceptual distortions, an inability to tolerate close friendships, and odd behavior, but they are not psychotic and so have generally not been prescribed neuroleptics nor hospitalized. Evaluation of brain structure in SPD may thus offer insight into the "endophenotype" common to both disorders. In addition, differences between groups may suggest which are the brain structures of schizophrenics that contribute to the development of psychosis. METHODS: To test the hypothesis of whether SPD subjects might show similar STG abnormalities, STG and medial temporal lobe regions of interest (ROI) were manually drawn on high resolution coronal MRI 1.5 mm thick slices. Images were derived from 16 right-handed male SPD subjects, without regard to family history, and 14 healthy, right-handed, comparison males who did not differ from the SPD group on parental socio-economic status, age, or verbal IQ. RESULTS: As predicted, SPD subjects showed a reduction in left STG gray matter volume compared with age and gender matched comparison subjects. SPD subjects also showed reduced parahippocampal left/right asymmetry and a high degree of disordered thinking. Comparisons with chronic schizophrenics previously studied by us showed the SPD group had a similarity of left STG gray matter volume reduction, but fewer medial temporal lobe abnormalities. CONCLUSIONS: These abnormalities strengthen the hypothesis of a temporal lobe abnormality in SPD, and the similarity of STG findings in schizophrenia and SPD suggest that STG abnormalities may be part of the spectrum "endophenotype." It is also possible that presence of medial temporal lobe abnormalities may help to differentiate who will develop schizophrenia and who will develop the less severe schizophrenia spectrum disorder, SPD.

Adult↗

Classification of medullary venous malformations in the temporal lobe: according to location and drainage pathway.

Medullary venous malformation (MVM) is rare in the temporal lobe, and the radiologic characteristics of temporal MVM have not yet been clarified. In 12 previously reported cases with satisfactory angiographic or magnetic resonance information as well as two newly reported here, we analyzed the specific location and hemodynamics of temporal lobe MVMs, particularly with respect to venous drainage. Temporal lobe MVM typically were seen in the superior lateral portion of the temporal lobe near either the atrium or the inferior horn of the lateral ventricle. Venous drainage was classified into two main patterns: deep (three cases) and superficial (11 cases). Superficial drainage could be divided into two subtypes: lateral and anterior. Dilated deep medullary veins converged toward either the lateral wall of the atrium or the inferior horn of the lateral ventricle. In the deep-drainage type, medullary veins drained into subependymal veins such as the inferior ventricular vein and the lateral atrial vein, and then emptied into the basal vein of Rosenthal. The anastomotic lateral mesencephalic vein was involved in one case as a variant of the basal vein. When the subependymal veins and/or the basal vein of Rosenthal or transverse sinus were hypoplasic, the medullary veins drained into either the Sylvian veins (anterior superficial type) or the vein of Labbé (lateral superficial type) through a characteristic large transcerebral vein. Drainage of temporal lobe MVM can be classified as deep, lateral superficial, or anterior superficial.

Adult↗

Chemosensory event-related potentials in patients with temporal lobe epilepsy.

We investigated chemosensory functions in patients with temporal lobe epilepsy (TLE) to discover whether olfactory and trigeminal stimuli applied either ipsilaterally or contralaterally to the epileptic focus are processed differently. Twenty-two patients were investigated, 12 of whom had epilepsy with a focus located in left temporal lobe (LTL). The remaining 10 patients had a right temporal lobe (RTL) focus. Input from the trigeminal system was examined by use of CO2; input from the olfactory system was evaluated with vanillin and hydrogen sulfide as stimuli. Chemosensory function was assessed by evaluation of chemosensory event-related potentials (CSERP) and the patients' verbal reports in an odor identification test. In both groups of patients, prolonged CSERP latencies were noted after stimulation of the left nostril with CO2 as compared with stimulation of the right nostril. In contrast, a different pattern emerged for olfactory stimuli. After right-sided olfactory stimulation, latencies were prolonged in patients with right-sided epileptical foci. Similarly, when the left nostril was stimulated in patients with a left-sided focus, CSERP latencies were prolonged. Thus, neocortical processing of olfactory, but not trigeminally mediated information evidently is affected by functional lesions of the temporal lobe. After olfactory stimulation in patients with a right-sided focus, the distribution of amplitudes was different from normal. Moreover, analyses showed nonoverlapping 95% confidence intervals (CI) for latency N1 when vanillin was applied to the right nostril. These results indicate that RTL may play a different role in processing of olfactory information as compared with LTL.

Adult↗

Negative symptoms and psychosocial status in temporal lobe epilepsy.

PURPOSE: To determine the relationship between negative symptoms, psychosocial function and quality of life in temporal lobe epilepsy. METHODS: 23 patients with temporal lobe epilepsy with negative symptoms were matched on gender, age, years of education, duration and age of epilepsy onset with 23 temporal lobe epilepsy patients exhibiting no negative symptoms as determined by a standardized rating system (SANS/SAPS). The matched groups were compared in regard to: (1). employment status, (2). dependence on government financial subsidy, (3). relationship/marital status, and (4). self-reported quality of life. RESULTS: Temporal lobe epilepsy patients with negative symptoms exhibited higher rates of unemployment, dependence on government aid, social isolation, and poorer self-reported quality of life relative to temporal lobe patients without negative symptoms. CONCLUSIONS: Interictal negative symptoms are associated with significantly increased psychosocial morbidity and poorer quality of life in temporal lobe epilepsy.

Adult↗

Neural responses associated with positive and negative emotion processing in patients with left versus right temporal lobe epilepsy.

Studies on emotion processing in patients with temporal lobe epilepsy have dealt mainly with the processing of negative emotions. To further understand the neural basis of emotional disorders in temporal lobe epilepsy, we studied patterns of brain activation induced by implicit processing of negative and positive emotions perceived through facial expressions and emotionally salient stimuli in candidates for surgical treatment of intractable epilepsy. Using functional MRI, we compared, in patients with mesial temporal lobe epilepsy and healthy subjects, the patterns of brain activation elicited by the implicit processing of fearful, sad, and happy faces and pleasant and unpleasant scenes. The results revealed different patterns of activation in patients with left and right mesial temporal lobe epilepsy, compared with healthy subjects, suggesting that the left and right mesial temporal regions are involved differently in emotion processing, which could be related to different contributions in emotional arousal.

Adult↗

Recent advances of PET in temporal lobe epilepsy.

Recent advancement of PET studies in patients with temporal lobe epilepsy was reviewed. Changes of receptor plasticity are also examined in the experimental model of temporal lobe epilepsy in rats with unilateral injection of Kainic acid into the basolateral portion of the amygdala. The characteristic changes of receptor function in the specific topographical areas in both hippocampi with and without any morphological changes in these rats were observed. We plan to investigate these changes of receptor plasticity by PET with 11C-labeled ligands in patients with temporal lobe epilepsy in the near future to obtain a better understanding of the mechanisms of temporal lobe epilepsy.

Amygdala↗

Cognitive outcomes in patients with chronic temporal lobe epilepsy.

Cognitive impairment is frequent in temporal lobe epilepsy (TLE). In particular, specific deficits in temporal lobe related functions occur, but deficits in extratemporal lobe functions and global intelligence are also found. The degree and type of the impairment are first determined by structural damage and functionally dynamic factors. Most cognitive problems in TLE are already detectable at, or even before, the onset of the epilepsy. Accumulation of damage during the course of chronic epilepsy may add to this. This additional damage may be caused directly by severe seizures, head trauma, intoxication etc., or indirectly by interference of the epilepsy with mental development. Surgical treatment of TLE may also affect the cognitive outcome of patients with chronic TLE, with a risk of additional impairments on the one hand and functional recovery due to seizure control on the other hand. With regard to patient-associated factors, better baseline performance, younger age, cerebral plasticity, and good mental reserve capacities are associated with a better outcome. With regard to treatment-associated factors, prevention of additional brain dysfunction/damage and successful seizure control are important.

Chronic Disease↗

Polyglucosan bodies and temporal lobe epilepsy: an incidental finding or more?

This study reports on histological findings in the temporal lobe of a 36-year-old woman who underwent a right temporal lobectomy for pharmaco-resistant complex partial seizures. Since surgery, the patient has remained seizure-free. The patient had an established diagnosis of right temporal lobe epilepsy, based on video EEG recordings of seizures, MRI hippocampal atrophy, focal interictal hypometabolism on fluoro-desoxyglucose, hypofixation of Cl1-flumazenil in PET studies, and ictal intracerebral recordings. Biopsies were studied under light- and electron microscopy. Histology showed diffuse distribution of a large number of polyglucosan bodies (PBs) in the whole right temporal lobe white matter. PBs were mostly confined to the perivascular areas and in subpial zones rarely and were observed in the most superficial cortical layers. There was some neuronal loss, especially in opercular zone T , but no other histological lesion was found. Ultrastructurally, PBs were made of filamentous and amorphous material, and were found both in intra-astrocytic processes and in axons. The presence of numerous PBs in the temporal lobe of patients with refractory temporal lobe epilepsy has been reported in 3 patients in the literature. It raises the questions whether this histological abnormality could be related to the epileptogenic process as a cause or as a consequence.

Adult↗

Clinical and electrographic manifestations of lesional neocortical temporal lobe epilepsy.

To determine whether lesional neocortical temporal lobe epilepsy (NTLE) can be differentiated from mesial temporal lobe epilepsy (MTLE) during the noninvasive presurgical evaluation, we compared the historical features, seizure symptomatology, and surface EEG of 8 patients seizure free after neocortical temporal resection with preservation of mesial structures and 20 patients after anterior temporal lobectomy for MTLE. Seizure symptomatology of 107 seizures (28 NTLE, 79 MTLE) was analyzed. One hundred one ictal EEGs (19 NTLE, 82 MTLE) were reviewed for activity at seizure onset; presence, distribution, and frequency of lateralized rhythmic activity (LRA); and distribution of postictal slowing. Seizure symptomatology and EEG data were compared between groups, and sensitivity, specificity, and positive and negative predictive values were determined for variables that differed significantly. Multiple logistic regression was used to determine whether patients could be correctly classified as having MTLE or NTLE. MTLE patients were younger at onset of habitual seizures and more likely to have a prior history of febrile seizures, CNS infection, perinatal complications, or head injury. NTLE seizures lacked features commonly exhibited in MTLE, including automatisms, contralateral dystonia, searching head movements, body shifting, hyperventilation, and postictal cough or sigh. NTLE ictal EEG recordings demonstrated lower mean frequency of LRA that frequently had a hemispheric distribution, whereas LRA in MTLE seizures was maximal over the ipsilateral temporal region. We conclude that it may be possible to differentiate lesional NTLE from MTLE on the basis of historical features, seizure symptomatology, and ictal surface EEG recordings. This may assist in the identification of patients with medically refractory nonlesional NTLE who frequently require intracranial monitoring and more extensive or tailored resections.

Adult↗

Does the medial temporal lobe bind phonological memories?

The medial temporal lobes play a central role in the consolidation of new memories. Medial temporal lesions impair episodic learning in amnesia, and disrupt vocabulary acquisition. To investigate the role of consolidation processes in phonological memory and to understand where and how, in amnesia, these processes begin to fail, we reexamined phonological memory in the amnesic patient HM. While HM's word span performance was normal, his supraspan recall was shown to be markedly impaired, with his recall characterized by a distinctive pattern of phonological errors, where he recombined phonemes from the original list to form new response words. These were similar to errors observed earlier for patients with specifically semantic deficits. Amnesic Korsakoff's patients showed a similar, though much less marked, pattern. We interpret the data in terms of a model of lexical representation where temporal lobe damage disrupts the processes that normally bind semantic and phonological representations.

Aged↗

Temporal lobe volume determined by magnetic resonance imaging in schizotypal personality disorder and schizophrenia.

The volumes of the whole temporal lobe, the superior temporal gyrus and the corpus callosum were measured on magnetic resonance images from 13 patients with schizotypal personality disorder (SPD), 27 patients with schizophrenia, and 31 age- and sex-matched controls. Temporal lobe structures were traced on consecutive 1.2mm thick SPGR images. Both patient groups had smaller temporal lobes than normal volunteers, a difference that was more marked for the area outside the superior temporal gyrus than for the STG. Correcting for brain volume diminished differences between normal subjects and schizophrenia patients, but the differences between normal subjects and SPD patients remained. Normal volunteers and SPD patients showed significant correlations between the sagittal section area of the posterior portion of the corpus callosum, which carries temporal interhemispheric connections, and the white matter volume of the temporal lobe. While the sample size is modest, taken together, these results suggest that the psychopathological symptoms of SPD may be related to temporal gray matter loss with relatively intact white matter connectivity, while the cognitive and psychotic symptoms of schizophrenia may be related to temporal gray loss combined with disruption of normal patterns of white matter development.

Adult↗