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Biomedical subjects

A M Kanner

Publications and source records attributed to A M Kanner.

At least 19 recordsLinked to original sources
PubMed2000

Adding valproate to lamotrigine: a study of their pharmacokinetic interaction.

The addition of valproic acid (VPA) to a lamotrigine monotherapy regimen (LTG) results in a decrement of LTG clearance. Whether this effect is related to the dose or concentration at steady state (Css) of VPA is yet to be established. This study was conducted to determine whether the dose or Css of VPA were inversely related to LTG clearance in 28 patients with intractable epilepsy who were treated with a combination of LTG and VPA. Correlations between LTG clearance and the dose and Css of VPA and comparisons of LTG clearance during low and high doses of VPA demonstrated that the degree of inhibition of LTG clearance is independent of the dose and Css of VPA.

Adolescent↗
PubMed2000

The "forgotten" cross-tolerance between phenobarbital and primidone: it can prevent acute primidone-related toxicity.

PURPOSE: We report on the effect that pretreating patients with phenobarbital has on averting adverse events when primidone is introduced. METHODS: Thirty patients with intractable partial epilepsy were pretreated with phenobarbital before starting primidone. Therapy with primidone was started at a dosage of 500 mg/day, and the phenobarbital was stopped. The primidone dose was then increased by 125 to 250 mg every 3 weeks until adverse events or a seizure-free state was reached. All previous antiepileptic medications were tapered down to yield a primidone monotherapy regimen. RESULTS: Twenty-six patients (87%) tolerated the introduction of primidone with minimal or no adverse events. Only one patient had to discontinue primidone during the initial 4 weeks because of severe dizziness. This was the only patient in whom primidone monotherapy could not be reached because of adverse events. Three other patients experienced dizziness severe enough to interfere with their activities. This symptom disappeared in two patients after the dose was lowered; in the other patient, primidone was stopped and phenobarbital was restarted for another 4 days. No symptoms recurred when primidone was reintroduced on the fifth day. CONCLUSIONS: Pretreatment with phenobarbital can minimize the occurrence of intolerable adverse events associated with the introduction of primidone.

Adolescent↗
PubMed1999

Psychiatric and neurologic predictors of psychogenic pseudoseizure outcome.

OBJECTIVE: To investigate the patterns of occurrence of psychogenic pseudoseizures (PPS) of 45 consecutive patients during a 6-month period after diagnosis, and to determine whether psychiatric and neurologic variables identified previously in PPS patient series can predict their recurrence after diagnosis, and whether any of these variables are associated with a particular outcome pattern. METHOD: Postdiagnosis PPS recurrence was assessed twice: during the first month and during a period ranging from the second to the sixth month. Outcome was categorized as follows: class I, complete cessation of PPS; class II, PPS only during one of the two observation periods; and class III, persistent PPS during the two observation periods. The authors used a logistic regression model to identify predictors of PPS recurrence (versus no PPS) among four neurologic and nine psychiatric variables, and compared their frequency among the three outcome classes. RESULTS: Class I, n = 13 (29%); class II, n = 12 (27%); and class III, n = 20 (44%). The presence of an abnormal MR image predicted PPS recurrence during the second observation period with a 75% accuracy. The presence of all nine psychiatric variables predicted PPS recurrence during both the first and second observation periods with a 93% and an 89% accuracy respectively. Patients with a class III outcome had a markedly higher frequency of recurrent major depression, dissociative and personality disorders, and a history of chronic abuse. Patients with a class II outcome displayed a notably higher frequency of denial of stressors and psychosocial problems, refusal of treatment recommendations, and new somatic symptoms after disclosure of diagnosis. Conversely, one episode of major depression was the one common diagnosis in patients with a class I outcome. CONCLUSIONS: PPS outcome after disclosure of diagnosis can be predicted by the presence of certain psychiatric characteristics. More than one psychopathogenic mechanism appears to operate in PPS.

Adult↗
PubMed1999

Wada difference a day makes: interpretive cautions regarding same-day injections.

OBJECTIVE: To determine whether memory scores after second intracarotid amobarbital procedure (IAP) injections are affected by the time between the first and second injections. METHODS: Sixty-two patients received their second IAP injection on the day after the first injection. Forty-three other patients received the second injection on the same day as the first injection. Both groups underwent similar IAP protocols and memory assessments, except for the timing of the second injection. RESULTS: The second IAP memory scores in the two-day group were significantly higher (p < 0.05) than those in the one-day group. Timing of second injection was a significant correlate of second memory scores, but amobarbital dosage, first IAP memory score, and pre-IAP measures of memory and intelligence were not significant correlates. CONCLUSION: One-day and two-day IAP protocols do not result in similar memory scores after the second injection. Nineteen percent of a subset of patients in the one-day protocol were misclassified, in terms of IAP memory ratings, because of the deleterious effect of having both injections on the same day. It is recommended that correction scores be considered, for some patients who receive two IAP injections on one day, to approximate what the second IAP memory score would have been had the second injection occurred on a second day.

Adolescent↗
PubMed1999

Are we overusing the diagnosis of psychogenic non-epileptic events?

In order to determine how often results of video/EEG (V-EEG) studies may change the clinical diagnosis of paroxysmal events, we prospectively studied 100 consecutive patients (75 females, 25 males) admitted for diagnosis of recurrent paroxysmal spells. The presumed diagnosis of the referring physician was obtained. Episodes were classified as epileptic seizures (ES), psychogenic non-epileptic events (PNEE), or physiologic non-epileptic events (PhysNEE). Eighty-seven patients had diagnostic events. A final diagnosis of ES was made in 21 patients, PNEE in 39, PNEE + ES in 20, and PhysNEE in seven. All PhysNEE were unsuspected. ES were misdiagnosed as PNEE more frequently than the reverse (57% vs. 12%, P < 0.001). Among the 64 patients with recorded events who had been suspected of having PNEE, 14 (21.9%) were misdiagnosed: two had PhysNEE and 12 (18.75%) had ES. Among the 23 patients with recorded events who were thought to have ES, 12 (39.1%) were misdiagnosed: seven had PNEE, five PhysNEE. V-EEG changed the clinical diagnosis in 29.8% of the patients with recorded events. Our data suggests that clinicians have become more aware of PNEE since the advent of V-EEG and have little problem recognizing them. However, they may be more prone to make a false-positive diagnosis of PNEE in ES with some atypical features. At this point, efforts should be channeled to better training in the proper recognition of ES that mimic PNEE.

Adolescent↗
PubMed1999

Depressive disorders in epilepsy.

Depression is a common occurrence among epileptic patients and constitutes, along with anxiety disorders, the most frequent psychiatric condition in these patients. The relationship between depression and epilepsy is two-directional, because patients with major depression also have a higher frequency of epilepsy. In epileptic patients, depressive disorders can present as unipolar, bipolar, or dysthymic disorders. More characteristically, however, they present as an atypical depression, which can often go unrecognized for long periods of time. In the diagnostic evaluation of these patients, clinicians must rule out the possibility that the depressive disorder resulted from the administration of antiepileptic drugs (AEDs; e.g., barbiturates) or from the discontinuation of an AED with mood-stabilizing properties that were masking an underlying affective disorder. Although antidepressant drugs have been used in epileptic patients for a long time, to date there has only been one controlled study. The antidepressants of the family of selective serotonin reuptake inhibitors (SSRIs) should be considered as initial therapy for depressive disorders in these patients.

Depressive Disorder↗
PubMed1998

When should induction protocols be used in the diagnostic evaluation of patients with paroxysmal events?

PURPOSE: To determine the timing of spontaneous psychogenic nonepileptic events (PNEE) during video-EEG telemetry (VEEG), and the need to use induction protocols (IP). METHODS: We studied 100 consecutive patients (75 females, 25 males) admitted to our inpatient VEEG unit from July 1994 to June 1996 for differential diagnosis of paroxysmal events. We recorded the time to the first diagnostic spontaneous event, identified by the patient or a family member as typical. Episodes were classified as PNEE, physiologic nonepileptic events (PhysNEE), and epileptic seizures (ES). RESULTS: The mean duration of VEEG was 74+/-SD 54.1 h. In 82 patients, a diagnostic event occurred spontaneously. The first event was an ES in 22 patients, a PNEE in 53, and a PhysNEE in 7. The time to first diagnostic event was significantly shorter for PNEE than for ES [15.0+/-SD 16.3 h (range 5 min to 58 h) vs. 28.6+/-SD 34.0 h (range 1-110 h) F=15.621, p < 0.0001]. In the first 24 h, 77.4% of the patients with PNEE had an event. By 48 h, all but 2 (96.2%) had had diagnostic events. After the first 58 h of monitoring, all patients with PNEE experienced a spontaneous diagnostic event. CONCLUSION: Spontaneous events can be expected to occur within 48 h in most patients with PNEE. Therefore, if IP are to be used as a diagnostic tool, we suggest that they be withheld during the initial 48 h of VEEG monitoring.

Adolescent↗
PubMed1998

Rapid switchover to carbamazepine using pharmacokinetic parameters.

PURPOSE: The standard practice of switching patients to carbamazepine (CBZ) involves initiating a low dose and raising it by small increments until the desired dose is reached, to avoid intolerable adverse effects (AE). In a pilot study, a protocol using single-dose kinetic studies was developed to switch patients to CBZ through rapid-dose increments and to manage concurrent rapid taper of the previous antiepileptic drugs (AEDs) without causing AE. The purpose of this prospective study was (a) to reassess whether a rapid switchover to CBZ could be done with minimal or no AE and without causing an increase in seizures; (b) to determine whether the maintenance dose of CBZ predicted at the time of the single-dose kinetic study can yield the desired concentration at steady state (Css); and (c) to determine the degree to which the calculated maintenance dose of CBZ will need to be adjusted after the previous AED has been discontinued for a four-week period. METHODS: Twenty-five patients taking phenytoin (PHT) and/ or phenobarbital (PB) and/or primidone (PRM) underwent a rapid switchover to CBZ following a 10 mg/kg single-dose kinetic study (day 1) which allowed calculation of a maintenance dose necessary to yield a mean Css of 10.2 (+/-2.2) mg/l. On day 2, patients received a CBZ dose equivalent to 10 mg/kg + 200 mg; thereafter, they underwent daily dose increments of 200 mg until the calculated maintenance dose was reached. Dose increments were modified in the case of AE. Concurrent tapering of the previous AED was started as of day 1: PHT by 100 mg/day, while PB and PRM were stopped on day 1; PB was restarted before patients were to be discharged from the hospital if a PB serum concentration above 10 mg/l was identified at that time. Pharmacokinetic data and occurrence of AE were compared between the two groups at the time of the single-dose kinetic study, at the completion of the switchover to CBZ, and 4 weeks after discontinuation of the previous AED. RESULTS: All patients completed the switchover to CBZ within a mean time period of 6 days (+/-2), reaching a mean maintenance dose of 1,639 mg/day (+/-370) which yielded a mean Css of 11.3 (+/-3.2) mg/l. The maintenance dose had to be lowered by 20.4% (+/-8.3) in 59% of patients within the four-week period following discontinuation of at least one of the previous AEDs. None of the patients experienced an increase in seizure frequency relative to baseline. Fifteen (60%) patients had no AE; five (20%) experienced AE of mild severity. AE rated as moderately severe (n = 4) or severe (n = 1) occurred in patients with a static encephalopathy (p = 0.02, Fisher's exact test) and among patients > or =55 years (p = 0.017, Fisher's exact test). CONCLUSIONS: A rapid switch-over to CBZ from PHT, PB, or PRM can be carried out safely with no, or minimal, AE in young adults, unless they suffer from static encephalopathy.

Adult↗
PubMed1998

De novo psychogenic nonepileptic seizures after epilepsy surgery.

PURPOSE: The occurrence of de novo nonepileptic seizures (NES) after epilepsy surgery have been reported only twice in the literature (one article and one abstract). METHODS: We report three patients whose de novo NES were documented by video-EEG telemetry after epilepsy surgery. These patients were drawn from a sample of 166 consecutive patients who underwent epilepsy surgery at our center between 1989 and 1996. RESULTS: Two patients became seizure free after surgery, and one had significant improvement of her seizures. The interval between the date of surgery and the development of the symptoms was variable (8, 10, and 47 months, respectively). The clinical phenomena of NES differed from those of the epileptic seizures preceding surgery. Their diagnosis had not been suspected in two patients before the diagnostic video-EEG monitoring study. After the diagnosis of NES, spells stopped in two patients and recurred rarely in one. CONCLUSIONS: We conclude that de novo NES appears to occur rarely after epilepsy surgery. Given that the possibility of NES was suspected in only one patient, its incidence after surgery may be higher than so far reported. Physicians should therefore consider NES in the differential diagnosis of recurrent seizures after a seizure-free period after epilepsy surgery.

Adult↗
PubMed1997

When do sphenoidal electrodes yield additional data to that obtained with antero-temporal electrodes?

The advantage of using sphenoidal (SE) over antero-temporal electrodes (ATE) remains controversial among epileptologists. Yet, in a recently published study of 17 patients with seizures of antero-temporal origin (Kanner et al., 1995), we demonstrated that SE placed under fluoroscopic guidance (FPSE), in order to insure that their recording tips are positioned immediately below the foramen ovale (FO), yielded a significant advantage over SE placed with the standard blind method of insertion (BPSE), in both interictal and ictal recordings. This study was done to test the following hypothesis: FPSE advantage over BPSE and ATE resides in the recording of epileptiform activity with a restricted electric field. We compared spike voltages at FPSE, BPSE and ATE in sets of 5 randomly selected spikes per interictal focus, recorded in the course of separate monitoring studies with BPSE and FPSE. We represented the voltage differences as ratios, VATE/FPSE and VATE/BPSE and calculated a mean ratio for each spike set. The spikes' voltage was almost identical at BPSE and at ATE (mean VATE/BPSE = 0.94), while it was significantly higher at FPSE than at ATE (mean VATE/FPSE = 0.66; P < 0.001, t test). A significantly narrower electric field contour was found among interictal foci in which FPSE yielded additional data during interictal (P < 0.001) and ictal (P = 0.016) recordings. Conversely, VATE/FPSE did not differ from VATE/BPSE among interictal foci where FPSE failed to yield any advantage over BPSE in either interictal (P = 0.240), or ictal (P = 0.311) recordings. These findings prove that SE yield additional localizing data when recording epileptiform activity with a restricted field, provided that its recording tip is positioned below the FO. When distant from FO, SE can be expected to yield comparable data to that obtained with ATE.

Action Potentials↗
PubMed1996

Postictal psychiatric events during prolonged video-electroencephalographic monitoring studies.

BACKGROUND: Postictal psychiatric events presenting as postictal psychotic events and postictal nonpsychotic events are known to occur following seizure clusters. Accordingly, patients undergoing prolonged video-electroencephalographic (EEG) monitoring studies may be at increased risk of experiencing postictal psychiatric event, as they often have flurries of seizures during these studies. OBJECTIVES: To determine the annual incidence and clinical characteristics of postictal psychotic events and postictal nonpsychotic events in video-EEG monitoring studies in patients with partial seizure disorders and to identify potential pathogenic factors. RESULTS: Thirteen patients met the criteria for a postictal psychiatric event during the 18-month study period, 10 presenting as postictal psychotic events and three as postictal nonpsychotic events. The annual incidence of postictal psychiatric events at our monitoring unit for 1988 was 7.8%, 6.4% presenting as postictal psychotic events and 1.4% as postictal nonpsychotic events. Seven patients had their first-ever postictal psychiatric event during the monitoring study. In 12 of the 13 patients, the postictal psychiatric events mimicked well-defined psychiatric entities of shorter duration (mean, 66.5 hours); they appeared 12 to 72 hours after the last seizure and remitted spontaneously or with the use of low-dose psychotropic medication. No significant differences in EEG, neuroradiologic, psychiatric, medical, or psychosocial data were found between the patients with postictal psychiatric events and a group of 13 age-matched control patients. Follow-up data of comparable duration were available in nine patients with postictal psychiatric events and nine controls. Psychiatric events were reported more frequently by patients with postictal psychiatric events than by control patients (P=.03). In three patients, postictal psychiatric events converted to interictal events. CONCLUSION: These findings suggest that monitoring studies increase the risk for postictal psychiatric events, which neurologists need to be familiar with, as they represent important morbidity associated with these studies.

Adult↗
PubMed1996

Transient facial palsy in sphenoidal electrode placement.

PURPOSE: Sphenoidal electrode (SE) insertion can cause pain, for which local anesthesia with lidocaine or intravenous administration of fentanyl has been advocated by different epilepsy treatment centers. Transient facial palsies have been observed after SE insertion. Their frequency of occurrence, distribution, and duration have not been well characterized, however. We hypothesized that this complication is due to the effect of local anesthesia on the peripheral branches of the seventh cranial nerve. To test this hypothesis, we compared the incidence and characteristics of facial palsy during SE insertions performed with either local anesthesia or after intravenous fentanyl administration. METHODS: We performed a retrospective study in two patient groups. Group A consisted of 25 patients aged 28 +/- 8.2 years who underwent a prolonged video-EEG (VEEG) monitoring study with SE after subcutaneous infusion of 1% lidocaine in the insertion area. Group B included 25 patients aged 30.1 +/- 8.9 years whose SE were inserted after intravenous administration of 100-200 micrograms fentanyl. Blood pressure (BP) was monitored every 3-5 min throughout the procedure. RESULTS: Five patients (20%) from group A had a transient facial palsy; in 4, it was complete and in 1 it was partial; 1 patient had a bilateral facial palsy. Paresis lasted 1-7 min (mean 3.2 min). In all patients, the recovery was complete. None of the patients in group B had complications (p = 0.025, Fisher's exact test). CONCLUSIONS: Transient facial palsy is a relatively frequent complication of SE insertion when SE are placed under local anesthesia; patients should be forewarned of its possible occurrence.

Adult↗
PubMed1995

Tailored anterior temporal lobectomy. Relation between extent of resection of mesial structures and postsurgical seizure outcome.

OBJECTIVE: The purpose of this study was to assess the relationship between the extent of resection of mesial temporal structures and postsurgical seizure outcome in a group of patients who had undergone a tailored anterior temporal lobectomy. METHODS: Twenty-four patients with unilateral interictal and ictal foci restricted to anterior/mesial temporal regions underwent resection of mesial and temporal lateral structures, the extent of which was tailored by intraoperative electrocorticographic findings and functional mapping of eloquent cortex. The extent of resection was determined with postoperative magnetic resonance imaging scans, using a semiquantitative method, based on a 20-compartment model of the temporal lobe. The magnetic resonance imaging scans were rated by three investigators blinded to seizure outcome. Follow-up period ranged between 18 months and 5 years. RESULTS: Amygdala and hippocampus were spared in six patients; nine patients had a partial to total resection of amygdala, eight patients had a resection of amygdala and the anterior third of the hippocampus, and one patient underwent resection of amygdala and anterior two thirds of hippocampus. Twenty-one of the 24 patients were seizure free (Engel's class I) and three had rare seizures (Engel's class II). Among these three patients, one had a resection of amygdala; one had resection of amygdala and anterior third of hippocampus; while in the third patient, mesial structures were spared. CONCLUSION: These data suggest that in patients with an anterotemporal seizure focus, the sparing or limited resection of amygdala and/or hippocampus is not necessarily associated with a poor seizure outcome, as had been previously suggested, provided that the decision not to resect is based on the absence of epileptiform activity during intraoperative electrocorticography or during recordings with depth electrodes.

Adolescent↗