The diagnostic aid of routine EEG findings in patients presenting with a presumed first-ever unprovoked seizure.

Data are available on the yield of a single EEG recording in patients with epilepsy but there is little information on EEG findings as an aid in supporting the diagnosis of an epileptic event in patients presenting with a first-ever event suspected of being an unprovoked seizure. We retrieved files of patients above the age of 15 years admitted through the emergency room during 1991-1995 with presumed first-ever unprovoked seizure. There were 91 patients (age 50+/-24; 52 males), of whom 66% had a presumed seizure of unknown origin and 34% had presumed remote symptomatic seizures. About 80% had generalized seizures (primarily or secondarily). In all the patients an EEG had been performed within 48 h of the event. Abnormal EEGs were obtained in 69%, with epileptiform activity in 21% (10% focal, 9% generalized and 2% focal and generalized), slowing in 58% (21% focal, 31% generalized and 7% focal and generalized), and both epileptiform activity and slowing in 10%. Epileptiform activity was most common in younger patients with seizures of unknown origin, compared with older individuals with symptomatic seizures (34, 38 vs. 27%, 7%, P=0.001). We conclude that following a single unprovoked presumed seizure, adults commonly exhibit abnormalities in an EEG recorded close in time to the event. The EEG is particularly helpful in supporting the epileptic nature of the event in younger patients and in those with seizures of unknown origin.

Physically traumatic events in patients with epilepsy compared with non-epileptic subjects.

To determine the incidence of traumatic events among epileptic patients compared with non-epileptic individuals, we distributed a questionnaire on physically traumatic events occurring during the preceding three months to consecutive epileptic patients and to age- and sex-matched controls. There were 145 epileptic patients, 121 with seizures (age 36 +/- 15 y, 60 males) and 24 who were seizure free during this period (age 39 +/- 17 y, 13 males), and 145 controls (age 36 +/- 15 y, 73 males). There was no significant difference in the duration of epilepsy between the two groups of patients with epilepsy. Traumatic events (n= 27, three of them unrelated to seizure) were most common in patients with seizures, followed by controls (n= 20), and absent in seizure-free patients (P< 0.001). Patients with epilepsy most commonly injured the head while the extremities were more usually involved in controls. Patients with epilepsy had significantly more traumatic events at home, whereas controls underwent most traumatic events at work and in public areas. There was no significant difference in the type and severity of trauma between the two groups. We conclude that physically traumatic events not related to seizures are fewer among patients with epilepsy with and without seizures compared with controls, probably because of increased cautiousness.

Intermittent rhythmic delta activity (IRDA) morphology cannot distinguish between focal and diffuse brain disturbances.

IRDA (intermittent rhythmic delta activity) is an abnormal generalized EEG pattern that is not specific to any single etiology and can occur with diffuse or focal cerebral disturbances. To determine whether different electrographic features of IRDA and associated EEG findings can differentiate underlying focal from diffuse brain disturbances, we performed a blind analysis of 58 consecutive EEGs with an IRDA pattern, recorded from 1993 until 1996, in which we evaluated posterior background activity, focal slowing and IRDA characteristics (frequency, distribution, duration, symmetry and abundance). The clinical diagnosis, state of consciousness and CT brain findings were retrieved from the patients' hospital records. There were 58 patients (33 females; mean age, 58+/-21 years). Twelve (21%) had only focal brain lesions, while 46 (79%) had diffuse brain abnormalities, (15 diffuse structural, 19 metabolic abnormalities, 12 postictal). Normal consciousness and focal EEG slowing were more frequent in patients with focal abnormalities, however, this was not statistically significant. Of the patients with focal abnormality, 11 (92%) had normal posterior background activity either bilaterally (n=4) or contralateral to the focal lesion (n=7). Bilaterally normal posterior background activity was observed in about 30% in both groups. Bilaterally abnormal posterior background activity was apparent in one patient (8%) with focal brain lesion and in 31 patients (67%) with diffuse brain abnormalities (P<0.0001). There were no significant differences in IRDA electrographic features between the focal group and the group with diffuse brain disturbances. We conclude that IRDA morphology cannot distinguish between focal and diffuse brain abnormalities.

Life-long history of injuries related to seizures.

There is meager information in the literature regarding the characteristics and risk factors for injuries caused during epileptic seizures in adults. Previous studies focused mainly on specific types of injuries incurred, and only few explored associated risk factors. A questionnaire regarding lifetime seizures and their traumatic consequences was administered to 298 consecutive epileptic patients and their caretakers or relatives. Ninety-one of them (30%) have reported trauma: 185 events (age 39.8+/-18 years, 54 males), of which 61 were severe. This translates to one seizure-related injury every 21 patient-years, and a serious injury once every 64 patient-years. The most common site of injury was the head (55% of the events). Blunt injuries occurred most frequently (40%), followed by cuts (28%). Severe injuries included fractures and dislocations (17%), burns (6%), brain concussion (6%), subdural hematoma (3%) and intracerebral hematoma (1%). Most injuries occurred at home. The 91 patients with traumatic events were compared with the 207 epileptic patients without previous trauma (age 37.8+/-14.7 years, 112 males). Patients with seizure-related trauma had significantly earlier onset age of epilepsy. They more commonly had generalized from onset tonic-clonic, complex partial, myoclonic or absence seizures but fewer had partial seizures with secondary generalization. The risk of trauma was mostly related to seizure type (generalized tonic clonic from onset and myoclonic seizures). This information may be helpful for better management of epileptic patients.

Comparison of the effects of vigabatrin, lamotrigine, and topiramate on quantitative EEGs in patients with epilepsy.

Information on the effects of newer antiepileptic drug (AEDs) on the electroencephalogram (EEG) is sparse and contradictory. Quantitative EEG (qEEG) provides a method of estimating the effects of drugs on the central nervous system. Twenty-three adult patients with difficult-to-control complex partial seizures, with or without secondary generalization, participated in an add-on study with one of three newer AEDs: vigabatrin (n = 10), lamotrigine (n = 6), and topiramate (n = 7). Frequency analysis and topographic mapping of awake EEGs before and during treatment with the drug were compared. Statistical analysis was performed using 2-way analysis of variance (ANOVA) with repeated measures. Vigabatrin administration was followed by a diffuse decrease in the absolute alpha (p < 0.05) and beta (p < 0.02) activities and a decrease in the absolute theta in the frontal and parieto-occipital regions (p < 0.03). Lamotrigine caused a significant diffuse increase in the faster frequencies (relative alpha p < 0.04 and relative beta p < 0.02), and decrease in the slower activities (relative theta in the posterior head regions p < 0.03 and relative delta diffusely p < 0.05). Topiramate increased the absolute beta (p < 0.05) and theta (p < 0.02) activities diffusely and decreased the relative alpha activity over the left hemisphere (p < 0.03). The different effect profiles of the newer AEDs on the electrical brain activity may reflect their different mechanisms of action.

Postmeningitis headache.

Acute meningitis is associated with headache, but the natural history of the headache following recovery is unknown. We addressed this issue in 141 patients admitted during 1990 to 1993 with laboratory-confirmed meningitis. We excluded patients younger than 5 years (n=44), elderly demented patients (n=6), and those with potential causes of headache other than meningitis (n=4). Seventeen candidates could not be traced. The remaining 70 patients were interviewed using a semistructured questionnaire that documented age, sex, type of meningitis, time of headache onset after infection, and headache description as well as any past and/or family history of headache. These patients were compared to age- and sex-matched controls (n=70). Prior to meningitis, 13 patients (19%) had had headaches (migrainous in 8) as did 18 controls (26%; migrainous in 8). Headache first appeared after meningitis in 19 patients (33%; migrainous in 6), increasing the total prevalence to 46%. We found no association between sex, type of meningitis, or family history and the development of postmeningitis headache. Patients who developed postmeningitis headache were significantly younger than those who did not. We conclude that there is an association between meningitis, either bacterial or aseptic, and subsequent persistent recurrent migrainous or nonmigrainous headache.

Sequential serum creatine kinase determination differentiates vaso-vagal syncope from generalized tonic-clonic seizures.

MATERIALS AND METHODS: In a prospective study we evaluated patients with first generalized tonic-clonic seizure (GTCS) (n = 16, age: 31 +/- 11 years, 8 women) and patients with vaso-vagal syncope (VVS) (n = 17, age: 32 +/- 13 years, 8 women), diagnosed on the basis of past history and clinical presentation who had serum creatine kinase (CK) levels assessed at admission to the emergency room and 24-26 h later. Patients with physical injuries were excluded. RESULTS: On admission, CK levels were > 130 mU/ml (2.16 microkat/l) in 25% (4/16) GTCS vs 6% (1/17) VVS patients; 24 h later, the figures were 56% (9/16) vs 12% (2/17) respectively. For GTCSD patients CK level > 200 mU/ml (3.33 microkat/l) had a sensitivity and specificity of 0.12 and 0.94 on the first day, and 0.25 and 1.0 respectively on the second day. The change in the CK level from the first to the second day was 155 +/- 266 mU/ml (2.58 +/- 4.43 microkat/l) for GTCS group and -2 +/- 37 mU/ml (-0.03 +/- 0.61 microkat/l) in VVS. An increase of more than 15 mU/ml (0.25 microkat/l) was observed in 11/16 GTCS patients and only in 1/17 VVS patients. Taking an increase of > 15 mU/ml (0.25 microkat/l) as a cut-off value, the sensitivity of this figure is 0.69 and specificity 0.94. An increase of > 15 mU/ml (0.25 microkat/l) in CK level among the patients with normal CK on both days was seen in 50% of GTCS but in none with VVS. Using the criteria of CK levels > 200 mU/ml (3.33 microkat/l) (on either day) and/or elevation from the first to the second day of > 15 mU/ml (0.25 microkat/l), there were only 12% false negatives and 12% false positives. CONCLUSIONS: We conclude that a higher increase in CK levels from the first to the second day occurs in GTCS as compared to VVS, and even when both sequential tests are within the normal range, an increase of at least 15 mU/ml (0.25 microkat/l) is highly indicative of an epileptic event. CK levels above 200 mU/ml (3.33 microkat/l) are unlikely to be the result of VVS.

The electroencephalogram in acetazolamide-responsive periodic ataxia.

Acetazolamide-responsive periodic ataxia (ARPA) is a rare movement disorder, characterized by recurrent episodes of vertigo, cerebellar ataxia, and nystagmus, which has recently been characterized genetically. The pathophysiology is unknown, but it is probably not epileptic. By definition, acetazolamide produces an impressive symptomatic relief. Because of the paroxysmal nature of the disorder, EEG tracings were often obtained. We report four new cases (two familial and two sporadic) with typical ARPA (none of whom had metabolic abnormalities or continuous electrical muscle activity) and review the EEG findings associated with this disorder. EEG findings were reported in 18 kindreds and nine sporadic cases (including ours). EEG was described in 54 of the 140 affected cases and was abnormal in 52% (28/54). Most commonly seen was intermittent generalized slow activity, observed in 35% (19/54), frequently intermingled with spikes (10 cases). Other abnormalities included nonspecific mild generalized or focal slowing in seven (13%) and focal epileptic activity in two (4%) patients. The paroxysmal EEG activity frequently seen in ARPA should not establish a diagnosis of epilepsy. Although not specific, it may suggest the correct diagnosis and indicate treatment with acetazolamide.