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Biomedical subjects

I Drury

Publications and source records attributed to I Drury.

At least 19 recordsLinked to original sources
PubMed2000

Increased secondary generalization of partial seizures after temporal lobectomy.

OBJECTIVE: This study tests the primary hypothesis that secondary generalization of partial seizures is more likely after anterior temporal lobectomy (ATL) than before ATL, and the secondary hypothesis that antiepileptic drug withdrawal accounts for increased generalization of seizures postoperatively. BACKGROUND: The authors observed that some patients had generalized tonic-clonic (GTC) seizures after but not before ATL, by using a new classification of outcome that compares preoperative and postoperative seizure frequencies by seizure type. METHODS: Twenty patients with refractory temporal lobe epilepsy had postoperative GTC seizures or nongeneralizing complex partial (CP) seizures in a consecutive ATL series. All had reduced seizure frequency postoperatively and more than 2 years of follow-up on antiepileptic drugs. The authors calculated a generalization fraction, as (number of GTC seizures)/(number of CP and GTC seizures), for 2 years before and 2 years after surgery. RESULTS: Postoperative generalization fractions were greater than preoperative generalization fractions (Wilcoxon signed-rank test, p < 0.01). Most postoperative GTC seizures were not associated with antiepileptic drug withdrawal, and postoperative GTC seizures were not more associated with drug withdrawal than were postoperative CP seizures. Patients with more than two GTC seizures per year preoperatively were more likely than other patients to have postoperative GTC seizures. CONCLUSIONS: Patients with reduced seizure frequency after ATL have a greater tendency for partial seizures to secondarily generalize postoperatively. This phenomenon is not explained by antiepileptic drug withdrawal.

Anticonvulsants↗
PubMed2000

The value of pelvic thrusting in the diagnosis of seizures and pseudoseizures.

We evaluated pelvic thrusting as a potential diagnostic sign and localizing indicator of ictal onset. By reviewing the video-EEG results of patients with temporal lobe epilepsy, frontal lobe epilepsy, generalized epilepsy, and pseudoseizures. Pelvic thrusting occurred in 4% of right and 2% of left temporal lobe epilepsy patients, in 24% of frontal lobe epilepsy patients, and in 17% of patients with pseudoseizures. Pelvic thrusting is relatively common in frontal lobe epilepsy and in pseudoseizures, but also occurs in temporal lobe epilepsy.

Adolescent↗
PubMed2000

Ictal spiking patterns recorded from temporal depth electrodes predict good outcome after anterior temporal lobectomy.

PURPOSE: Investigators have shown that the presence of ictal spiking (IS) recorded from temporal depth electrodes is associated with mesial temporal sclerosis (MTS). We investigated the relation of IS to seizure control and pathology after anterior temporal lobectomy (ATL). METHODS: All patients undergoing intracranial ictal monitoring from a single institution since 1989 were identified. Those who did not undergo ATL or had postoperative follow-up of <1 year were excluded. All received at a minimum bilateral temporal depth electrodes. Ictal recordings were reviewed for the presence of IS, and the proportion of seizures with IS was determined for each patient. Outcome was determined by using Engel's classification. Surgical specimens were reviewed for pathology. Statistics used were chi2, Fisher exact test, and Wilcoxon rank sum. RESULTS: Forty patients with 571 seizures were reviewed. In 292 seizures from 32 patients, IS was seen. Outcomes were 24 class I (22 with IS), five class II (four with IS), three class III (one with IS), seven class IV (four with IS), and one lost to follow-up (with IS). Pathologic review revealed 25 with MTS, 22 of whom had IS. The presence of IS was associated with class I outcomes (p = 0.04), but not MTS (p = 0.06). Patients with class I outcomes had a significantly greater proportion of seizures with IS (mean, 0.58 +/- 0.3) compared with other outcomes (mean, 0.30 +/- 0.3, p = 0.02). CONCLUSIONS: The presence of IS and higher proportion of seizures with IS correlated with good seizure outcome after ATL. This information may be used in preoperative counseling.

Electrodes, Implanted↗
PubMed2000

Nonepileptic seizure outcome varies by type of spell and duration of illness.

PURPOSE: To determine whether differences in clinical manifestations of psychogenic nonepileptic events are associated with differences in outcome and whether the length of illness before diagnosis correlates with outcome. METHODS: We reviewed ictal videotapes and EEGs in 85 patients diagnosed with exclusively nonepileptic psychogenic seizures during inpatient CCTV-EEG monitoring at the University of Michigan between June 1994 and December 1996. They were classified into groups of similar ictal behaviors. Fifty-seven of these patients were available to respond to a follow-up telephone survey about their condition 2-4 years after discharge. We examined demographics, baseline EEG abnormalities, and outcome of treatment interventions. We also evaluated whether interventions were more likely to succeed if patients were diagnosed early in the course of the illness. RESULTS: We found that the largest groups consisted of patients with motionless unresponsiveness ("catatonic," n = 19) and asynchronous motor movements with impaired responsiveness ("thrashing," n = 19). Infrequent signs included tremor, automatisms, subjective events with amnesia, and intermittent behaviors. There was a higher incidence of baseline EEG abnormalities in the thrashing group (31%) than in the catatonic group (0%). There was a higher incidence of complete remission of spells in the catatonic group (53%) than in the thrashing group (21%). Patients who had a more recent onset of seizures (most often within 1 year) were much more likely to have remission of spells after diagnosis. CONCLUSIONS: Classification of nonepileptic seizures is useful in predicting outcome and may be valuable in further investigation of this complex set of disorders.

Adult↗
PubMed1999

Postictal nose-rubbing in the diagnosis, lateralization, and localization of seizures.

BACKGROUND: Semiology is very useful in the diagnosis and classification of seizures. Some clinical signs occur primarily with specific localization-related epilepsies. OBJECTIVE: To evaluate postictal nose-rubbing as a potential diagnostic sign and a potential lateralizing or localizing indicator. METHODS: We reviewed presurgical prolonged video-EEG results of 50 consecutive patients with right temporal lobe epilepsy (TLE), 50 consecutive patients with left TLE, 50 consecutive patients with frontal lobe epilepsy, 11 consecutive patients with generalized epilepsy, and 100 consecutive patients with nonepileptic events. Videotapes of all events were reviewed independently by two investigators who were blinded to the results of the monitoring. The episodes of nose-rubbing and the hand with which the patient rubbed the nose were recorded. RESULTS: Nose-rubbing occurred in 25 of 50 (50%) right TLE patients and in 21 of 50 (42%) left TLE patients. Approximately 90% of patients rubbed his or her nose with the ipsilateral hand. Nose-rubbing occurred in 5 of 50 (10%) frontal lobe epilepsy patients. Nose-rubbing was not seen in any patient with generalized epilepsy or nonepileptic events. Postictal nose-rubbing did not occur after secondarily generalized seizures. CONCLUSIONS: Nose-rubbing is an easily observed phenomenon, has high interobserver reliability, and provides useful lateralizing information in patients with TLE. It was less frequently seen in extratemporal lobe epilepsy and was not seen after generalized seizures or nonepileptic events.

Adolescent↗
PubMed1999

Indications and outcome of ictal recording with intracerebral and subdural electrodes in refractory complex partial seizures.

Intracranial electrophysiologic recording has often been used to localize ictal onset zones in presurgical evaluation of refractory complex partial seizures. Specific indications for intracranial ictal monitoring have not been analyzed in detail, however. The authors designed this study to test the utility of intracranial monitoring in specific indications and considered six specific indications for intracranial monitoring. They compared prospectively determined indications and outcomes of chronic intracerebral and subdural electrophysiologic recording in 50 consecutive patients whose ictal onset zones had been inadequately localized with interictal and ictal EEG using extracranial electrodes, magnetic resonance imaging, interictal[18F]fluorodeoxyglucose positron emission tomography, and neuropsychological testing. In 47 patients ictal onset zones were localized with intracranial recordings, leading to resections in 38 patients. Each indication for intracranial monitoring selected a group in which the majority went on to have efficacious epilepsy surgery (5-year follow-up). Definitive diagnosis of bilateral independent ictal onset zones in temporal lobe epilepsy required intracranial ictal EEG. Intracranial EEG localization supported efficacious resection in most patients, despite contradictory or nonlocalizing extracranial ictal EEG and neuroimaging abnormalities. Critical analysis of these specific indications for intracranial monitoring may be useful in multicenter evaluation of these techniques.

Brain↗
PubMed1999

Value of inpatient diagnostic CCTV-EEG monitoring in the elderly.

PURPOSE: To examine the outcome of inpatient diagnostic closed circuit TV-EEG (CCTV-EEG) monitoring in a consecutive series of elderly patients admitted to an adult epilepsy-monitoring unit (EMU) over a continuous 6-year period. METHODS: Retrospective review of all admissions to a university hospital adult EMU. Those older than 60 years were identified. Patients who were monitored for status epilepticus were excluded. Data on duration of events, frequency of events, physical examination, medications, preadmission EEG, brain imaging, length of stay, and interictal and ictal EEG were obtained. RESULTS: Of the 18 patients admitted for monitoring only, mean age was 69.5 years (range, 60-90 years). Mean length of stay was 4.3 days (range, 2-9 days). Five patients had complex partial seizures recorded. Three patients, all treated with anti-epileptic drugs (AEDs), had no spells recorded, and no additional diagnostic information was gained from the admission. The other 10 patients, eight of whom had been treated with AEDs, were symptomatic during their admission, leading to a variety of neurologic but not epileptic, psychiatric, or other medical disorders, and allowing tapering of AEDs. CONCLUSIONS: In elderly patients with suspected epilepsy, CCTV-EEG is a very useful diagnostic tool. In this series of 18, 10 patients were diagnosed with potentially treatable medical illnesses not responsive to AEDs.

Adult↗
PubMed1998

Influence of head trauma on outcome following anterior temporal lobectomy.

BACKGROUND: There is controversy in the literature regarding the importance of risk factors in developing epilepsy and seizure outcome following anterior temporal lobectomy. Some of the existing studies may be biased because of patient selection and limitations in determining predisposition. OBJECTIVE: To investigate the role of risk factors for epilepsy in determining outcome following anterior temporal lobectomy. PATIENTS AND METHODS: We identified 102 patients in a consecutive surgery series for epilepsy from a tertiary center with a minimum of 1-year postoperative follow-up. Risk factors for epilepsy were determined prospectively on at least 3 occasions before anterior temporal lobectomy. Risk factors investigated were a history of febrile convulsions, family history of epilepsy, significant head trauma, history of meningitis, history of encephalitis, or significant perinatal insult. Foreign tissue lesions on magnetic resonance imaging was also included if an anterior temporal lobectomy was performed for presumed dual pathologic findings (hippocampus and lesion). Outcome was determined using Engel's classification. For statistical analysis we used successive logistic regression analysis, chi(2) test, Fisher exact test, and t test. RESULTS: Of the 102 patients, 13 had no identified risk factor for epilepsy, 49 had 1 identified risk factor, and 40 had more than 1. Frequencies were 39 febrile convulsions (15 complex febrile convulsions), 29 head trauma, 22 with lesions seen on magnetic resonance imaging, 12 history of meningitis, 2 history of encephalitis, 19 family history of epilepsy, and 4 perinatal insult. Seventy-one (70%) were classified as Engel's class I, with 56 patients continuously free of seizures at follow-up. Those without risk factor were as likely to be rendered free of seizures following anterior temporal lobectomy as those with a risk factor (P = .27). No risk factor alone or in combination was correlated with complete freedom from seizures following anterior temporal lobectomy, but the presence of head trauma, alone or in combination, was correlated with continued seizures following anterior temporal lobectomy (P = .03; odds ratio, 2.6). Better outcomes were not seen in those with head trauma before the age of 5 years (P = .57). These findings did not change if all those with lesions on magnetic resonance imaging were excluded in the analysis. Those with a history of head trauma were as likely to have pathologic evidence of mesial temporal sclerosis as others (P = .82). CONCLUSIONS: Patients with a history of significant head trauma are less likely to become free of seizures following anterior temporal lobectomy. No other risk factor correlated with a statistically significant greater or lesser chance of freedom from seizures. This information may be used in preoperative counseling of patients.

Adult↗
PubMed1998

Interictal epileptiform activity in elderly patients with epilepsy.

OBJECTIVE: To examine the frequency of interictal epileptiform activity (IEA) in elderly patients with epilepsy. DESIGN AND METHODS: From a consecutive 13,905 EEGs recorded over 5 years at a university hospital EEG laboratory, 558 studies were performed on outpatients aged 60 years or more. Medical record review identified 125 patients in whom a confident clinical diagnosis of epilepsy was made by a board-certified neurologist. The EEG findings in these patients were reviewed. The effects of various variables on the likelihood of detecting IEA were calculated using Fisher's test and chi-square analysis. RESULTS: IEA were present on the first EEG in 35% of 55 patients (mean age 65 years) with pre-existing epilepsy, and 26% of 70 patients (mean age 70 years) with seizure onset after 60 years. There were no significant differences in the frequency of IEA in patients with late onset epilepsy in the 7th or in the 8th decades of life. Most IEA were focal. Activation procedures added little additional information. Patients with more than one seizure per month were significantly more likely to have IEA (P = 0.016). There were no major differences in likelihood of IEA detection depending on the underlying cause of the seizures. CONCLUSIONS: The frequency of IEA in elderly patients with epilepsy is substantially lower than that reported in epileptic populations as a whole. This low rate of IEA in routine EEG studies must be recognized when considering the diagnosis of an epileptic syndrome for episodic events happening in the elderly.

Aged↗
PubMed1998

Responses to photic stimulation in patients with occipital spikes.

OBJECTIVE: To determine the effect of intermittent photic stimulation (IPS) and frequency of asymmetric driving responses in patients with occipital spikes. METHODS: The amplitude of the driving response at 4 flash frequencies was measured from a referential montage in 60 patients with occipital spikes and in 60 normal EEG records from age-matched patients. Responses were classified as asymmetric if the amplitude at one occipital area was less than 50% of the amplitude at the other. RESULTS: A measurable photic response occurred significantly less frequently in patients with occipital spikes (48%) compared to the control group (70%; Fisher's test P < 0.05). The driving response was asymmetric in 7/36 patients (37%) with unilateral spike foci versus none in the control group (Fisher's test, P < 0.001). The amplitude was suppressed ipsilateral to the focus in 5 patients, all of whom had an ipsilateral structural lesion or focal slowing. In two cases the amplitude was higher ipsilateral to the focus, neither having slowing or a structural lesion. CONCLUSIONS: Patients with occipital spikes have an increased frequency of asymmetric driving response. An attenuated response ipsilateral to the focus seems to be related to an underlying lesion while the presence of an epileptiform focus in some cases with no slowing on EEG and normal imaging studies may lead to an accentuation of this response.

Adolescent↗
PubMed1998

Ictal behaviors during nonepileptic seizures differ in patients with temporal lobe interictal epileptiform EEG activity and patients without interictal epileptiform EEG abnormalities.

PURPOSE: Ictal behaviors during psychogenic nonepileptic seizures (NES) vary considerably among individuals, and can closely resemble common semiologies of epileptic seizures (ES). We tested the hypothesis that behaviors during NES in patients who have temporal spikes would more closely resemble behaviors during ES in patients with temporal lobe epilepsy than would behaviors during NES in patients who do not have EEG spikes. METHODS: We identified 20 patients who had interictal temporal EEG spikes and EEG-video recorded NES (Study Group), 133 patients with temporal EEG spikes and recorded ES, without NES (Epileptic Group), and 24 patients with recorded NES and no epileptiform EEG abnormalities, without ES (Nonepileptic Group). RESULTS: The hypothesis was supported with regard to ictal motor behaviors. Motionless staring or complex automatisms occurred mainly during NES in the Study Group and during ES in the Epileptic Group. In contrast, convulsive movements or flaccid falls were most common during NES in the Nonepileptic Group. Duration of unresponsiveness was longer, and there were fewer postictal states in NES both in the Study and Nonepileptic Groups. Unresponsiveness was briefer and postictal states were more consistent in ES in the Epileptic Group, however. CONCLUSIONS: Stereotyped motor activities during NES presumably represent learned behaviors. Processes underlying acquisition of ictal behaviors of NES probably differ in patients with interictal epileptiform EEG abnormalities compared to those without. Prior experiences and temporal lobe dysfunctions that are associated with epilepsy, and psychological characteristics that are unrelated to interictal epileptic dysfunctions, may determine ictal behaviors during NES.

Adult↗
PubMed1997

Ictal patterns in temporal lobe epilepsy recorded by epidural screw electrodes.

In a consecutive series of 11 patients with a history of medically refractory temporal lobe epilepsy, we studied the appearance of ictal patterns detected by epidural screw electrodes (ESE) placed in an effort to obviate depth electrode recording. All had prior scalp-sphenoidal monitoring with significant obscuration of ictal EEG by movement and muscle artifact. Six to 10 ESE were placed at bilateral temporal locations of the 10% system. Ictal findings in 4-15 partial seizures from 8 patients with mesiobasal (MBTLE) and 3 patients with neocortical (NCTLE) epilepsy were correlated with imaging and histology. Five of 8 patients with MBTLE had discrete high frequency discharges at onset, evolving within 10 s to focal theta at ESE, before appearing at scalp electrodes. All had Class IA outcome with mesial temporal sclerosis (MTS). Three of 8 patients with MBTLE and MTS had less discrete onsets, with Class 1A, 1B and 3A outcomes. Two patients with NCTLE had lesions; a grade II oligoastrocytoma with rhythmic delta at ESE and Class 4 outcome, and an anterior temporal cavernous angioma with variable onsets, some of which were high frequency, with a Class 1A outcome. The third NCTLE patient demonstrated focal theta as an ictal pattern, had no lesion and a Class 1A outcome. Ictal onsets may be well localized in selected patients by ESE. A majority of patients with MTS display well defined high frequency ictal discharges.

Adolescent↗
PubMed1997

Mutual information analysis and detection of interictal morphological differences in interictal epileptiform discharges of patients with partial epilepsies.

The purpose of this paper is to compare the morphological features of interictal epileptiform discharges (IED) in patients with benign epilepsy of childhood with centrotemporal spikes to IED of those with symptomatic localization related epilepsies using information theory. Three patients from each clinical group were selected. Two-second epochs centered at the peak negativity of the sharp waves were analyzed from a referential montage during stage I sleep. The epochs from the two groups were compared using parametric and information theory analysis. Information analysis determined the likelihood of correctly identifying the clinical group based on the IED. Standard parametric, morphological and spectral analyses were also performed. We found no significant difference in the morphology of the sharp wave between the two groups. The after-going slow wave contained the greatest information that separated the two groups. This result was supported by morphological and spectral differences in the after-going slow wave. Greater distinguishing information is held in the after-going slow wave than the sharp wave for the identification of clinical groups. Information analysis may assist in differentiating clinical syndromes from EEG signals.

Adult↗
PubMed1997

Relative value of the inion and mid-parietal locations as additional recording sites in pattern reversal visual evoked potentials.

Although the P100 response of pattern reversal visual evoked potentials (PRVEPs) is most commonly recorded from the midline occipital site (MO), the response at this location can occasionally be absent or poorly defined due to anatomical variability of the visual cortex. In these cases, the American Electroencephalographic Society Evoked Potential Guidelines recommends recording from the mid-parietal (MP) and Inion electrode sites. In this study, we compared the amplitude of the P100 component recorded simultaneously from MO, MP and the Inion. PRVEPs obtained following stimulation with 30' check sizes from 155 consecutive patients (310 eyes) over a 2 year period were analyzed. At each of the 3 recording sites, the peak amplitude of P100 was calculated as N75-P100, P100-N145, and the sum of N75-P100 and P100-N145. There was a statistically significant difference between the electrode sites for all 3 methods of amplitude measurement (one-way ANOVA; P < 0.0001). For each method of measurement, there was no significant difference between P100 amplitude at MO or the Inon, but a significantly reduced amplitude at MP compared to both the MO and Inion electrode sites (post hoc Scheffe, P < 0.05). The P100 amplitude was highest at the Inion in 18% of responses, including cases where the amplitude at that site was at least twice that at MO. In no case was the amplitude highest at MP. Our results indicate that the Inion is a better recording site compared to MP when acquiring PRVEPs, is often complementary to MO, and should be the first additional site to be used when extra channels are available.

Adolescent↗
PubMed1997

Non-epileptic seizures in temporal lobectomy candidates with medically refractory seizures.

Diagnosis of epileptic seizures is often based on temporal lobe epileptiform abnormalities appearing on interictal EEG, when reported ictal semiologies are consistent with temporal lobe seizures. It is unclear how often such patients have non-epileptic seizures. We studied 145 patients who had temporal interictal EEG spikes and reported ictal semiology characteristic of temporal lobe seizures, with long-term EEG-video-monitoring (LTM) for presurgical evaluation of medically refractory seizures. Nonepileptic seizures were unexpectedly recorded in 12 of these patients (8%). Outcomes after LTM in patients who had both epileptic seizures and nonepileptic seizures demonstrated that the epileptic seizures usually were controlled with medications. Our observations support LTM as useful in diagnosis of non-epileptic seizures in this group of patients. We suggest that ictal recordings always should be performed before epilepsy surgery, in part to avoid unintentional surgical treatment of nonepileptic seizures.

Adolescent↗