Christine Kilpatrick

Onset seizures independently predict poor outcome after subarachnoid hemorrhage

Objective: To determine whether onset seizures after subarachnoid hemorrhage (SAH) carry independent prognostic information and to investigate the risk factors for late seizures after SAH. Background: Modern management of SAH, including early operation, has substantially reduced mortality. No study has adequately assessed the importance of onset seizures in a contemporary SAH cohort. Methods: The authors analyzed the records and initial CT scans of 412 consecutive patients with aneurysmal or nonaneurysmal SAH admitted to the Royal Melbourne Hospital from 1990 to 1996. Each patient with an onset seizure (n = 32, 7.8% of cohort) was age and sex matched to two nonseizure patients of the same cohort. Each patient with a late seizure (n = 17, 5.1% of cohort) was matched to five control subjects of the same cohort. Results: With use of logistic regression analysis, onset seizures correlated with the sum score of blood on initial CT scan (OR = 1.1, p = 0.05), but there was no significant correlation with duration of loss of consciousness at onset, Glasgow Coma Score (GCS), presence of aneurysm, or past history of hypertension or epilepsy. Disability 6 weeks after SAH according to the Glasgow Outcome Scale was independently predicted by initial GCS of <6 (OR = 13.7, p < 0.01) and onset seizure (OR = 7.8, p = 0.04). Late seizures within the first 6 weeks were independently related to rebleeding (OR = 94, p < 0.01) and onset seizures (OR = 27, p < 0.01) but not to other onset variables, development of hydrocephalus, or vasospasm. Conclusion: In this single-institution cohort of patients with SAH, onset seizures were an independent risk factor for late seizures and a predictor of poor outcome.

Hippocampal Atrophy Is Not a Major Determinant of Regional Hypometabolism in Temporal Lobe Epilepsy

Summary: Purpose: The pathophysiologic basis for the [18F]fluorodeoxyglucose positron‐emission tomography (FDG‐PET) temporal lobe hypometabolism in patients with hippocampal sclerosis (HS) is uncertain. We tested the hypothesis that hippocampal atrophy, which is strongly correlated with hippocampal cell loss, is largely responsible for the regional hypometabolism in HS.

Epilepsy Surgery for Pathologically Proven Hippocampal Sclerosis Provides Long‐term Seizure Control and Improved Quality of Life

Summary:  Purpose: To examine long‐term seizure and quality‐of‐life outcome in a homogeneous group of patients after temporal lobectomy with pathologically proven hippocampal sclerosis (HS). Previous research has had limited follow‐up (generally <2 years) and has grouped patients across multiple pathologies.

Degree of left hippocampal atrophy correlates with severity of neuropsychological deficits

The relationship between the degree and distribution of hippocampal atrophy measured by volumetric magnetic resonance imaging and severity of memory deficits in 25 patients with temporal lobe epilepsy secondary to mesial temporal sclerosis was assessed. Hippocampal volumes were expressed as a ratio of smaller to larger, normal ratio greater than 0.95. Neuropsychology tests included: subtests of the WAIS-R, Rey Auditory Verbal Learning Task, Rey Figure and the Austin Maze. Degree of left hippocampal atrophy in patients with left temporal lobe epilepsy was associated with severity of verbal memory deficits as measured by RAVLT total recall (P < 0.05), delayed recall (P < 0.001), story recognition (P < 0.001), list recognition (P < 0.001) and final delayed recall (P < 0.001) and recall of the Rey Figure (P < 0.01). There was no association between degree of right hippocampal atrophy and any of the memory tests. Diffuse left hippocampal atrophy was associated with more severe verbal memory deficits than anterior atrophy. We conclude, the association between degree of left hippocampal atrophy and verbal memory provides further evidence of the predominant involvement of the left hippocampus in verbal memory. The finding of a relationship between degree of left hippocampal atrophy and measures of non-verbal function suggests these tests are dependent on verbal memory, or that mesial temporal sclerosis is a bilateral but asymmetrical condition.

Seizure Frequency and Duration of Epilepsy are Not Risk Factors for Postoperative Seizure Outcome in Patients with Hippocampal Sclerosis

Summary: Purpose: Despite accurate localization of the seizure focus, not all patients are seizure free after temporal lobectomy. This study determined risk factors for seizure recurrence in patients with proven hippocampal sclerosis.

Non-invasive investigations successfully select patients for temporal lobe surgery

OBJECTIVES There is controversy regarding the need for invasive monitoring in the preoperative assessment of patients with temporal lobe epilepsy. The use of a series of non-invasive investigations in identifying the seizure focus is reported in 75 consecutive adults referred for epilepsy surgery. METHODS All had video-EEG monitoring using scalp electrodes, high resolution MRI, and neuropsychology assessment. Other investigations included volumetric MRI, PET, and ictal and interictal SPECT. The seizure focus was localised and surgery offered if MRI disclosed unilateral hippocampal atrophy or a foreign tissue lesion and other investigations were either concordant or not discordant. RESULTS In 68 patients the seizure focus was localised and three patients were inoperable. Sixty five patients have been offered surgery and 50 have undergone temporal lobe surgery and have a follow up of at least 12 months (mean 24 months). All had pathology: hippocampal sclerosis 34, dysembryoblastic neuroepithelial tumour six, cavernoma four, dysplasia two, low grade glioma two, ganglioglioma two. Thirty nine patients (78%) are seizure free postoperatively, 29/34 with hippocampal sclerosis and 10/16 with a foreign tissue lesion. Of the 11 patients with postoperative recurrent seizures, eight have a >90% reduction in seizure frequency and three have <90% reduction in seizure frequency but a worthwhile improvement. CONCLUSIONS Non-invasive investigations successfully select most patients for temporal lobe surgery.

Neuropsychiatric morbidity in focal epilepsy

BACKGROUND Previous work has identified elevated prevalence rates for psychiatric disorders in individuals with medically refractory focal epilepsy, particularly temporal lobe epilepsy. Many studies were undertaken before the advent of video electroencephalogram monitoring (VEM) and magnetic resonance imaging (MRI). AIMS To investigate which characteristics of the focal epilepsy syndromes are associated with the presence of depression or psychosis. METHOD Three hundred and nineteen individuals with focal epilepsy admitted for VEM were seen over an 11-year period. The lifetime history of depression and psychosis, epileptic site, laterality and type of lesion were determined by clinical assessment, VEM and MRI scan. RESULTS There was a significant association between the prevalence of depressive symptoms and non-lesional focal epilepsy. There were no significant differences in prevalence of neuropsychiatric disorders between the groups with temporal lobe epilepsy and those with extratemporal lobe epilepsy. CONCLUSIONS These findings contrast with previous findings in smaller cohorts. The association between non-lesional focal epilepsy and depression may be due to the effects of a more diffuse epileptogenic area.

The Liverpool Adverse Events Profile: Relation to AED Use and Mood

Summary:  Purpose: The Liverpool Adverse Events Profile (LAEP) is used as a systematic measure of adverse effects from antiepileptic drugs (AEDs). This study evaluated LAEP in newly diagnosed seizure patients, and examined the relation between LAEP, anxiety, and depression.

Clinical characteristics and outcome in patients with psychogenic nonepileptic seizures.

Objectives: To examine baseline clinical features of psychogenic nonepileptic seizures (PNES) in a large cohort and to investigate outcome over a period of up to 10 years. Studies investigating PNES have been limited by differences in diagnostic criteria, short follow-up periods, and the use of limited outcome measures. Method: Patients with PNES were identified, using strict diagnostic criteria. Baseline neurological, neuropsychiatric, and neuroimaging data were obtained from medical records. Long-term outcome was assessed with ratings of seizures, psychopathology, and quality of life in a subset of the patients. Results: Patients with PNES (n = 221) experienced long delays in diagnosis (&mgr;, 5.6 years; standard deviation, 7.7 years) and high rates (>60%) of prolonged treatment with antiepileptic drugs. Compared with previous studies, a relatively low proportion (8.1% to 17.9%, depending on diagnostic criteria) had comorbid epilepsy. An unexpected finding was that 22.6% of PNES patients had magnetic resonance imaging abnormalities. Patients assessed at follow-up (n = 61) exhibited poor long-term outcomes with ongoing PNES, high rates of psychopathology, low rates of specialist follow-up, poor quality of life, and poor overall levels of functioning. Conclusions: These results demonstrate the need for earlier diagnosis of PNES and comorbidities and highlight the need for diagnostic and therapeutic approaches that combine neurological and psychiatric perspectives. PNES = psychogenic nonepileptic seizures; VEM = video-electroencephalographic monitoring; EEG = electroencephalogram; AEDs = antiepileptic drugs; MRI = magnetic resonance imaging; ES = epileptic seizures; QOL = quality of life.

Amygdala volumetry in “imaging-negative” temporal lobe epilepsy

Objective: Although amygdala abnormalities are sometimes suspected in “imaging-negative” patients with video EEG confirmed unilateral focal epilepsy suggestive of temporal lobe epilepsy (TLE), amygdala asymmetry is difficult to assess visually. This study examined a group of “imaging-negative” TLE patients, estimating amygdala volumes, to determine whether cryptic amygdala lesions might be detected. Methods: Review of video EEG monitoring data yielded 11 patients with EEG lateralised TLE and normal structural imaging. Amygdala volumes were estimated in this group, in 77 patients with pathologically verified hippocampal sclerosis (HS), and in 77 controls. Results: Seven of 11 “imaging-negative” cases had both significant amygdala asymmetry and amygdala enlargement, concordant with seizure lateralisation. Although significant amygdala asymmetry occurred in 35 of 77 HS patients, it was never attributable to an abnormally large ipsilateral amygdala. Compared with patients with HS, patients with amygdala enlargement were less likely to have suffered secondarily generalised seizures (p<0.05), and had an older age of seizure onset (p<0.01). Conclusion: Abnormal amygdala enlargement is reported in seven cases of “imaging-negative” TLE. Such abnormalities are not observed in patients with HS. It is postulated that amygdala enlargement may be attributable to a developmental abnormality or low grade tumour. It is suggested that amygdala volumetry is indicated in the investigation and diagnosis of “imaging-negative” TLE.