Biomedical subjects
Publications and source records attributed to M Koutroumanidis.
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OBJECTIVE: To compare the neuropsychological effects of temporal lobectomy (TL) and amygdalohippocampectomy (AH), depending on whether the patients had passed or failed the Wada test. METHODS: We compared changes in neuropsychological scores in patients who underwent TL (n = 91) or AH (n = 15), and had passed or failed the Wada test. Comparisons were carried out in all 106 patients and among the 20 patients who failed the Wada test (12 who had TL and 8 who had AH). RESULTS: No patient became globally amnesic after surgery. Among all patients, no differences were found in pre-surgical or change scores (percentage of change after surgery compared with preoperative values) of neuropsychological tests between patients who underwent TL or AH. Among patients who failed the Wada test, those in the TL group showed higher visual memory impairment (p<0.05). There was a strong trend suggesting that TL is associated with higher verbal memory deficits than AH (p = 0.07). Of those TL patients who failed the Wada test, the contralateral Wada score correlated with change scores in verbal intelligence quotient (p<0.01), and there was a strong trend towards a correlation with the logical memory immediate recall version subtest of the Wechsler Memory Scale (p = 0.06). CONCLUSIONS: No profound changes in intelligence quotient or memory scores were found after TL or AH. Nevertheless, patients who underwent TL and failed the Wada test showed more deficits than those who passed the test or those who had AH. The presence of a correlation between contralateral Wada scores and verbal deficits in TL patients who failed the Wada test but not among AH patients suggests that, if temporal surgery is required, AH might be preferred to TL in patients who fail the Wada test.
OBJECTIVES: To assess the efficacy of vagus nerve stimulation (VNS) in patients with medically and surgically intractable complex partial seizures (CPS). PATIENTS AND METHODS: Sixteen patients with previous temporal [15] and frontal [one] resections were treated with VNS between 1994 and 1999 at King's College Hospital, London, UK. Post-operative video-electroencephalogram telemetry had shown that CPS started from the operated side in 12 patients, contralaterally in three and bilaterally independently in one. RESULTS: Three patients (18.75%) had 50% or more reduction in seizure frequency, but one showed severe worsening of epilepsy, which remitted upon VNS discontinuation. The antiepileptic effect of VNS was not different with respect to the type of operation (anterior temporal lobectomy vs amygdalohippocampectomy), the side of operation, or the side of seizure onset. We observed psychotropic effects in two patients with post-ictal psychosis, in two others with depression, and in a child with severe behavioral disorder. CONCLUSIONS: VNS may have a rather limited antiepileptic role to play in patients with persistent seizures following epilepsy surgery, but may independently possess useful antipsychotic and mood-stabilizing properties.
Three of 282 consecutive patients who had temporal resections for intractable epilepsy developed postoperative postictal psychosis. These three patients had seizure recurrence contralateral to the resection, whereas none of the patients with ipsilateral seizure recurrence developed any psychiatric symptoms after surgery. Two had left amygdalo-hippocampectomy and one right temporal lobectomy. The de novo occurrence of postoperative postictal psychosis is a well-defined complication of surgery for temporal lobe epilepsy, and may relate to contralateral epileptogenesis.
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The authors report two adult patients with chronic temporal lobe epilepsy and pathologic features consistent with Rasmussen's encephalitis. Although seizures persisted after temporal lobe surgery no progressive cognitive or neurologic deficit has emerged. Prominent auditory auras in each suggested a persisting epileptogenic focus in the superior temporal gyrus. The current findings expand the clinical spectrum of Rasmussen's encephalitis and suggest that chronic nonprogressive encephalitis may serve as the pathologic substrate of medically intractable temporal lobe epilepsy.
OBJECTIVE: To describe the association between a unilateral mid-temporal rhythmic theta discharge ("psychomotor variant of Gibbs") with neuroimaging-demonstrated underlying mass lesion. METHODS: Standard routine awake and scalp electroencephalography, continuous video-EEG monitoring and magnetic resonance brain imaging were employed in the diagnostic work-up of a 9-year-old boy with a severe behavioural disturbance and episodic outbursts of aggression. RESULTS: EEG showed a unilateral mid-temporal rhythmic discharge which was continuous in drowsiness and which remained confined to the right hemisphere. MRI showed a lesion in the temporal horn of the right lateral ventricle displacing superiorly the white matter stem of the right temporal lobe. CONCLUSION: A rhythmic mid-temporal theta discharge, commonly regarded as a benign EEG variant, may, in some patients, reflect underlying structural pathology. Neuroimaging should be considered particularly when this EEG pattern remains confined to one hemisphere.
PURPOSE: To estimate the significance of residual electrocorticographic and neuropathologic abnormalities on seizure control after surgery for frontal lobe epilepsy with the purpose of determining their relevance in deciding the extent of the surgical procedure. METHODS: The presence of epileptiform discharges in intraoperative electrocorticograms (ECoGs) and the nature and extent of neuropathologic abnormalities were reviewed for 35 patients who underwent frontal lobe resections for the treatment of epilepsy at our institution. The relations between surgical outcome and presence of the following features were studied: (a) presence of abnormal tissue at the limits of the resection; (b) presence of sporadic spikes and seizure patterns in the preresection ECoG; (c) their abolition in the postresection ECoG; and (d) the topography of residual discharges with respect to the margins of the resection. RESULTS: On neuropathologic examination, 18 patients showed focal cortical dysplasia (CD), and 17 showed other abnormalities (non-CD). Ten CD patients and 11 non-CD patients experienced a favourable outcome. Seizure patterns were significantly more common in patients with focal cortical dysplasia than in those without, with a sensitivity of 94% and a specificity of 75%. Abolition of seizure patterns was associated with a favourable surgical outcome (p = 0.031). Abolition of sporadic spikes or their presence in the postresection ECoG did not influence outcome. There was no clear relation between outcome and location of residual sporadic discharges. Seizure patterns persisted in the postresection ECoG in three CD patients, were located at the margins of the resection in all three, and these patients had a poor outcome. Incomplete removal of abnormal tissue was not associated with a poorer outcome in either patient group or in the complete sample. CONCLUSIONS: Seizure patterns were significantly more common in patients with cortical dysplasia, and their abolition on postresection ECoG recordings was associated with a favourable surgical outcome. Persistence of sporadic ECoG spikes and incomplete removal of histologic abnormalities did not affect outcome significantly.
We report a 28-year-old woman of normal intellect, who had three late-onset seizures with unusual ictal features and secondary generalization during prolonged and vigorous tooth brushing. Neurologic examination and brain magnetic resonance imaging (MRI) were normal, but interictal EEG showed left frontal epileptiform activity. Reasonable precautions (regular but briefer and less vigorous brushing of her teeth) combined with a moderate dose of carbamazepine effectively prevented seizure recurrence. This case may be an example of cryptogenic form of reflex epilepsy with seizures induced exclusively by tooth brushing.
PURPOSE: The value of scalp recordings to localize and lateralize seizure onset in temporal lobe epilepsy has been assessed by comparing simultaneous scalp and intracranial foramen ovale (FO) recordings during presurgical assessment. The sensitivity of scalp recordings for detecting mesial temporal ictal onset has been compared with a "gold standard" provided by simultaneous deep intracranial FO recordings from the mesial aspect of the temporal lobe. As FO electrodes are introduced via anatomic holes, they provide a unique opportunity to record simultaneously from scalp and mesial temporal structures without disrupting the conducting properties of the brain coverings by burr holes and wounds, which can otherwise make simultaneous scalp and intracranial recordings unrepresentative of the habitual EEG. METHODS: Simultaneous FO and scalp recordings from 314 seizures have been studied in 110 patients under telemetric presurgical assessment for temporal lobe epilepsy. Seizure onset was identified on scalp records while blind to recordings from FO electrodes and vice versa. RESULTS: Bilateral onset (symmetric or asymmetric) was more commonly found in scalp than in FO recordings. The contrary was true for unilateral seizure onset. In seizures with bilateral asymmetric onset on the scalp, the topography of largest-amplitude scalp changes at onset does not have localizing or lateralizing value. However, 75-76% of seizures showing unilateral scalp onset with largest amplitude at T1/T2 or T3/T4 had mesial temporal onset. This proportion dropped to 42% among all seizures with a unilateral scalp onset at other locations. Of those seizures with unilateral onset on the scalp at T1/T2, 65.2% showed an ipsilateral mesial temporal onset, and 10.9% had scalp onset incorrectly lateralized with respect to the mesial temporal onset seen on FO recordings. In seizures with a unilateral onset on the scalp at electrodes other than T1/T2, the proportions of seizures with correctly and incorrectly lateralized mesial temporal onset were 37.5 and 4.2%, respectively. Thus the ratio between incorrectly and correctly lateralized mesial temporal onsets is largely similar for seizures with unilateral scalp onset at T1/T2 (16.7%) and for seizures with unilateral scalp onset at electrodes other than T1/T2 (11.2%). The onset of scalp changes before the onset of clinical manifestations is not associated with a lower proportion of seizures with bilateral onset on the scalp, or with a higher percentage of mesial temporal seizures or of mesial temporal seizures starting ipsilateral to the side of scalp onset. In contrast, the majority (78.4%) of mesial temporal seizures showed clinical manifestations starting after ictal onset on FO recordings. CONCLUSIONS: A bilateral scalp onset (symmetric or asymmetric) is compatible with a mesial temporal onset, and should not deter further surgical assessment. Although a unilateral scalp onset at T1/T2 or T3/T4 is associated with a higher probability of mesial temporal onset, a unilateral onset at other scalp electrodes does not exclude mesial temporal onset. A unilateral scalp onset at electrodes other than T1/T2 is less likely to be associated with mesial temporal onset, but its lateralizing value is similar to that of unilateral scalp onset at T1/T2. The presence of clinical manifestations preceding scalp onset does not reduce the localizing or lateralizing values of scalp recordings.
The unusual case of newly-emerged bilateral myoclonus in a 39-year-old man following anterior temporal lobectomy, which cured his temporal lobe epilepsy, is reported. The possible causes and differential diagnosis between epileptic and non-epileptic myoclonus following epilepsy surgery are presented and a brief review of the available literature on the subject is reported.
A syndrome of idiopathic generalised epilepsy with phantom absences of undetermined onset has been recently described. This syndrome clinically becomes apparent in adulthood with generalised tonic clonic seizures and frequently absence status epilepticus. We report an 11 year-old normal girl with frequent episodes of absence status and no other overt clinical manifestations. However, appropriate video-EEG recordings documented that she had frequent absence seizures that were so mild as to escape recognition by her and the parents. These consisted of mild impairment of cognition and eyelid fluttering during brief generalised discharges of spike/multiple spike and slow waves. No further seizures occurred and the EEG normalised after appropriate drug treatment. Thus, it appears that this syndrome of phantom absences and absence status may start much earlier, in late childhood. Appropriate video-EEG documentation is needed for the recognition of these patients that may be more common than it appears from the few published cases (with Video).
OBJECTIVES: To investigate the relationship between recognition memory and metabolite levels in medial structures of the temporal lobes in the living human brain. METHODS: Proton MRS ((1)H MRS) and the intracarotid amobarbital test were performed in 16 epileptic patients found suitable for temporal lobectomy. All patients had mesial temporal sclerosis. Metabolite ratios between N:-acetylaspartate (NAA), creatine and phosphocreatine (Cr + PCr), and choline-containing compounds (Cho) [NAA/(Cr + PCr), NAA/Cho, and NAA/(Cr + PCr + Cho)] were calculated for (1)H MRS voxels that included the amygdala, anterior half of the hippocampus, and underlying subiculum. Metabolite ratios were correlated with unilateral memory scores estimated by the intracarotid amobarbital test for words, objects, faces, and total score. RESULTS: The total memory score, memory for objects and faces, and NAA/(Cr + PCr) were significantly lower for the hemisphere ipsilateral to the resection. The asymmetry indexes for NAA/(Cr + PCr) correlated with asymmetry indexes for words (rho = 0.82, p = 0.0001) and total memory (rho = 0. 72, p = 0.002). Analysis of memory scores and metabolite ratios from all 32 hemispheres revealed a correlation between NAA/(Cr + PCr) and memory for words (rho = 0.45, p = 0.009). A correlation between memory for words and NAA/(Cr + PCr) existed in the contralateral (rho = 0.58, p = 0.019) and in the right (rho = 0.51, p = 0.045) hemispheres, and a trend was found in the left hemispheres (rho = 0. 48, p = 0.06). CONCLUSION: There is a correlation between memory for words and the NAA/(Cr + PCr) ratio from medial temporal structures in patients with mesial temporal sclerosis. The findings suggest that medial temporal structures and adjacent neocortex play a significant role in recognition memory in humans, particularly for words.
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OBJECTIVE: To assess the clinical implications and the pathophysiologic determinants of interictal bitemporal hypometabolism (BTH) in temporal lobe epilepsy (TLE) not associated with bilateral MRI abnormalities or intracranial space-occupying lesions. METHODS: The authors compared the clinical, interictal, and ictal EEG, Wada test, and neuropsychology data of 15 patients with intractable complex partial seizures of temporal lobe origin and BTH with those of 13 consecutive patients with unilateral TLE associated with unilateral temporal hypometabolism (UTH) who remained seizure free for more than 3 years after anterior temporal lobectomy. 18F-fluorodeoxyglucose PET scans were analyzed visually and semiquantitatively, and ratios of counts in individual temporal areas to the rest of the cerebrum were compared with the corresponding values from 11 normal control subjects and with the nonepileptogenic hemisphere of the 13 patients with UTH. BTH was defined as more than 2.5 SDs below control values for two or more temporal areas on each side irrespective of any asymmetry. RESULTS: BTH reflected bilateral independent seizure onset in eight patients (53%). The topography of the metabolic depression was not a reliable predictor of epileptogenicity, but involvement of the inferior temporal gyrus was related specifically to ipsilateral seizure onset (70% sensitivity, 100% specificity). In patients with unilateral TLE, contralateral hypometabolism was associated with longer disease duration and worst memory performance during the Wada test, which amounted to global amnesia after ipsilateral injection in three patients, precluding surgical treatment. Contralateral seizure spread in the ictal EEG was significantly faster in patients with BTH. CONCLUSIONS: In TLE, symmetric or asymmetric BTH may signal bilateral independent seizure onset in approximately half the patients, especially when involving the inferior temporal gyrus. Alternatively, it may reflect an advanced stage of the disease process, characterized by a breakdown of the inhibitory mechanisms in the contralateral hemisphere, and secondary memory deficit associated with higher risk of postoperative memory decline. Patients with TLE and BTH but without bilateral MRI changes may still be operated on successfully, but surgical suitability should be proved by comprehensive intracranial EEG studies and Wada test.
We report the occurrence of an unusually sustained, non-reactive, bilateral, rhythmic, subclinical discharge in a young adult without epileptic seizures
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OBJECTIVE: To assess the interrelation of idiopathic generalized epilepsy (IGE) and temporal lobe epilepsy (TLE) when they coexist in the same patient. METHODS: The authors reviewed the electroclinical features of 350 consecutive patients who had temporal resection between 1975 and 1997 at the Maudsley and King's College Hospitals, London. RESULTS: Two patients had the unusual combination of TLE and IGE (0.57%). In the first, the clinical onset of juvenile myoclonic epilepsy followed the surgical resolution of his partial seizures but had been heralded for at least 5 years by subclinical spontaneous and photically induced generalized spike-wave discharges. In the second, TLE and juvenile absence epilepsy had a long parallel course before surgery. After surgery he had no further partial seizures. CONCLUSION: These cases suggest that when an idiopathic absence or myoclonic syndrome manifests in a patient with symptomatic TLE, the phenotype may not be a merged syndrome. Rather, the two conditions can retain their inherent electroclinical profile, responsiveness to treatment, and prognosis.