Do atmospheric pressure changes influence seizure occurrence in the epilepsy monitoring unit?

In a prior study of epilepsy and atmospheric pressure, we were able to show a small association between changes in atmospheric pressure and increased seizure frequency in consecutive patients with epilepsy undergoing video telemetry. In this study, we used a larger data set of similar patients undergoing telemetry at another Seattle institution, and examined the possible impact of atmospheric pressure (AP) changes on seizure onset in subtypes of seizures (focal, generalized, and nonepileptic). Comparisons were made between AP score at time of seizure onset and AP score at selected time ranges prior to the event (hour of seizure and 3, 6, and 24 hours prior) and a random sample of AP scores collected over similar time frames using nonparametric testing with correction for multiple comparisons. We could find no evidence to suggest atmospheric pressure changes made seizure occurrence more likely in any of the seizure groups across any of the time periods.

Side effects and mortality associated with use of phenytoin for early posttraumatic seizure prophylaxis.

OBJECT: The goals of this study were to determine if the use of phenytoin to prevent early posttraumatic seizures following head injury was associated with significant adverse side effects and also to determine if the reduction in early posttraumatic seizures after phenytoin administration was associated with a change in mortality rates in head-injured patients. METHODS: The authors performed a secondary analysis of the data obtained in a prospective double-blind placebo-controlled study of 404 patients who were randomly assigned to receive phenytoin or placebo for the prevention of early and late posttraumatic seizures. The incidence of adverse drug effects during the first 2 weeks of treatment, however, was low and not significantly different between the treated and placebo groups. Hypersensitivity reactions occurred in 0.6% of the patients in the phenytoin-treated group compared with 0% in the placebo group (p = 1.0) during week 1, and in 2.5% of phenytoin-treated compared with 0% of placebo-treated patients (p = 0.12) for the first 2 weeks of treatment. Mortality rates were also similar in both groups. Although the mortality rate was higher in patients who developed seizures, this increase was related to the greater severity of the injuries sustained by these patients at the time of the original trauma. CONCLUSIONS: The results of this study indicate that the incidence of early posttraumatic seizure can be effectively reduced by prophylactic administration of phenytoin for 1 or 2 weeks without a significant increase in drug-related side effects. Reduction in posttraumatic seizure during the 1st week, however, was not associated with a reduction in the mortality rate.

Risk of seizure recurrence after the first late posttraumatic seizure.

OBJECTIVE: To determine the incidence and risk factors for seizure recurrence after the onset of late posttraumatic seizures (ie, seizures occurring more than 7 days after injury). DESIGN: Longitudinal cohort design. SETTING: Level 1 trauma center. PATIENTS: Sixty-three moderately to severely head-injured adults who developed late posttraumatic seizures during the course of their participation in a randomized, placebo-controlled study of the effectiveness of prophylactic phenytoin (Dilantin) for prevention of posttraumatic seizures. MAIN OUTCOME MEASURES: Time from the first unprovoked late seizure to time of seizure recurrence. RESULTS: The cumulative incidence of recurrent late seizures was 86% by approximately 2 years. However, the frequency of recurrent seizures varied considerably across subjects: 52% experienced at least five late seizures, and 37% had 10 or more late seizures within 2 years of the first late seizure. The relative risk of recurrence was highest in patients with a history of acute subdural hematoma and prolonged coma (ie, longer than 7 days). CONCLUSIONS: When late seizures develop after severe head injury, the probability of recurrence is high, which suggests that patients be treated aggressively with anticonvulsant medication after a first unprovoked late seizure.

The impact of posttraumatic seizures on 1-year neuropsychological and psychosocial outcome of head injury.

This study examined the relationship of posttraumatic seizures and head injury severity to neuropsychological performance and psychosocial functioning in 210 adults who were prospectively followed and assessed 1 year after moderate to severe traumatic head injury. Eighteen percent (n = 38) of the patients experienced 1 or more late seizures (i.e., seizures occurring 8 or more days posttrauma) by the time of the 1-year followup. As expected, the head injured patients who experienced late posttraumatic seizures were those with the most severe head injuries, and they were significantly more impaired on the neuropsychological and psychosocial measures compared to those who remained seizure free. However, after the effects of head injury severity were controlled, there were no significant differences in neuropsychological and psychosocial outcome at 1 year as a function of having seizures. These findings suggest that worse outcomes in patients who develop posttraumatic seizures up to 1 year posttrauma largely reflect the effects of the brain injuries that cause seizures, rather than the effect of seizures.

Intracarotid amobarbital procedure and prediction of postoperative memory in patients with left temporal lobe epilepsy and hippocampal sclerosis.

PURPOSE: Although temporal lobe epilepsy (TLE) patients with dominant hemisphere hippocampal sclerosis generally have good cognitive outcome after anterior temporal lobectomy (ATL), a minority of patients experience at least mild post-ATL decline on one or more standardized measures of episodic and semantic memory. The goal of this investigation was to determine whether memory outcome in this group could be predicted from preoperative intracarotid amobarbital procedure (IAP) recognition memory scores. METHODS: Data from 22 left TLE patients were studied retrospectively. All were left hemisphere language dominant and had IAP scores for each hemisphere, a significant degree of pathology-confirmed left hippocampal sclerosis (HS+), and no positive MRI findings other than atrophy. Cognitive outcome status was represented by the number of pre- to post-ATL declines across three tests, as defined by 90th percentile Reliable Change Index (RCI) criteria. RESULTS: Only 14% of the sample exhibited decline on more than one memory test. Low right IAP (left hemisphere injection) scores and relatively high preoperative cognitive ability and age at surgery predicted a greater risk of post-ATL memory decline. CONCLUSIONS: A minority of left TLE HS+ patients experience at least a mild degree of RCI-defined decline in episodic or semantic memory after ATL. The right hemisphere IAP memory score, which reflects the functional reserve of the contralateral hemisphere, can help predict the risk of postoperative memory decline for TLE patients in whom HS+ is likely based on the presence of hippocampal atrophy on MRI or early age of seizure onset.

Ictal stuttering: a sign suggestive of psychogenic nonepileptic seizures.

OBJECTIVE: To determine if ictal stuttering (IS) is more common among patients with psychogenic nonepileptic seizures (PNES) than patients with epileptic seizures (ES). METHODS: The authors prospectively reviewed the medical records, EEG-video recordings, and Minnesota Multiphasic Personality Inventory-2 (MMPI-2) scores of consecutive adults of normal intelligence diagnosed with either PNES or ES. RESULTS: A total of 230 (117 PNES and 113 ES) patients were studied. PNES patients were older (p = 0.029), more likely to be female (p < 0.001), and had a shorter duration of seizure disorder (p < 0.001) than ES cases. Ten (8.5%) PNES subjects and no ES cases demonstrated IS. The proportion of patients with IS in these two groups was significantly different (p = 0.004). PNES patients with IS were of similar age as but had an even shorter (p = 0.010) duration of seizure disorder (mean = 3.0 years) than those without IS. Scores on the hypochondriasis, depression (D), and hysteria scales of the MMPI-2 were significantly higher among PNES subjects than in ES patients (p < or = 0.002). However, seven PNES patients with IS had a lower mean score on the D scale than did 98 PNES cases without stuttering (p = 0.005). This produced a more sharply defined "conversion V" appearance on the MMPI-2 graph in the stutterers. CONCLUSIONS: Ictal stuttering was present in 8.5% of 117 consecutive patients with psychogenic nonepileptic seizures, but was not observed in a consecutive series of 113 adults with epileptic seizures. Patients with psychogenic nonepileptic seizures with ictal stuttering had a shorter duration of seizure disorder and a more prominent conversion profile on the Minnesota Multiphasic Personality Inventory than either patients with psychogenic nonepileptic seizures without stuttering or subjects with epileptic seizures.

Temporal ictal electroencephalographic frequency correlates with hippocampal atrophy and sclerosis.

We studied 328 complex partial seizures (CPS) in 63 consecutive patients with temporal lobe epilepsy who underwent scalp electroencephalography/video monitoring, magnetic resonance imaging (MRI), and surgery. The initial ictal discharge (IID), defined as the first sustained electrical seizure pattern localized to the surgical site, was determined. If the IID was rhythmic waves, the median frequency was measured. To determine if IID frequency correlates with hippocampal atrophy (HA) or sclerosis (HS), hippocampal volume ratios (HVRs) were measured (n = 52) or assessed visually (n = 11) on MRI, and mesial temporal histopathology specimens (n = 22) were graded for HS. Sixteen patients (25%) had no or mild HA (HVR = 0.78-1.02), and 47 patients (75%) had moderate-to-marked unilateral (HVR = 0.33-0.76), or bilateral, HA. Theta frequency IIDs were significantly more commonly associated with moderate-to-marked HA than were delta IIDs. Theta frequency IIDs occurred in 19% of patients with mild or no HA, and 79% of patients with moderate-to-marked HA; delta IIDs occurred in 63% of patients with little to no HA, and 13% of those with moderate-to-marked HA. In addition, the median IID frequency inversely correlated with HVR and directly correlated with HS severity. In conclusion, faster frequency rhythmic IIDs during temporal lobe CPS correlate with greater degrees of ipsilateral HA on MRI, and higher grades of HS.