Is it time for individualized testing in the electroencephalogram (EEG) laboratory?

BACKGROUND AND PURPOSE: The interictal electroencephalogram (EEG) has an important role in the classification and treatment of epilepsy. In busy EEG laboratories, valuable resources are used in order to comply with current recommendations regarding the length of EEG recordings. Our aim was to examine the time to first interictal epileptiform discharge (IED) in standard and sleep-deprived EEGs. METHODS: Standard and sleep-deprived EEG recordings with IEDs were retrospectively reviewed during a 2-year period. Bedside EEGs and long-term video-EEGs were excluded. IED latency according to EEG type, age group and inpatient/outpatient status was analyzed with the Kaplan-Meier estimator. RESULTS: The study group included 684 patients, 372 (54%) males, aged 0.2-89 years. Standard (n = 316) and sleep-deprived (n = 368) EEGs were performed in 245 inpatients and 439 outpatients. The EEG was requested in 96% of the inpatients following a seizure. Most IEDs were recorded whilst the patients were awake (43%) or drowsy (34%). Ninety percent of the IEDs were recorded within 18.5 min, earlier in standard (14.6 vs. 21.3 min) (P = 0.024) EEGs and in inpatients (14 vs. 21.3 min) (P = 0.002). IED latency was unaffected by age. CONCLUSIONS: Electroencephalogram type and admission status may be used for individual determination of the duration of EEG recording. Reducing the duration of standard and sleep-deprived EEGs may be considered especially in inpatients.

The prognosis of refractory epilepsy patients rejected from epilepsy surgery.

OBJECTIVE: Up to one-third of individuals diagnosed as having epilepsy continue to have seizures despite appropriate anti-epileptic drug treatment. These patients are often referred for presurgical evaluation, and many are rejected from focal resective surgery due to medical reasons or, alternatively, they choose not to undergo it. We compared the outcomes and characteristics of the non-operated patients who continued on medical therapy alone with those who underwent vagus nerve stimulator (VNS) implantation in addition to medical therapy. METHODS: The medical records of consecutive adult patients referred for presurgical evaluation for suitability for epilepsy surgery in the Tel-Aviv Sourasky Medical Center between 2007 and 2011 and were rejected from or decided against surgery were reviewed. Updated information on seizure frequency was supplemented by telephone interviews between April and July, 2013. RESULTS: Fifty-two patients who continued solely on medical therapy and 35 patients who additionally underwent VNS implantation were included in the study. Forty-seven of the former and 33 of the latter agreed to be interviewed. There was a significant improvement in the seizure frequency between the time of the presurgical evaluation and the time of the interview in both groups. Eight medically treated patients (17%) and 2 patients who also underwent VNS implantation (6%) reported being seizure-free during the preceding 3 months. CONCLUSIONS: A considerable minority of patients with refractory epilepsy who were rejected or chose not to undergo epilepsy surgery may improve over time and even become seizure-free following adjustment of anti-epileptic drugs with or without concomitant VNS.

Clinical and electroencephalographic findings in acutely ill adults with non-convulsive vs convulsive status epilepticus.

BACKGROUND: Non-convulsive status epilepticus (NCSE) indicates a change in the mental state with no motor manifestations, being a clinical expression of prolonged epileptiform activity. In contrast to convulsive status epilepticus (CSE), no unified treatment recommendations have been proposed so far. We were interested to review the clinical and encephalographic characteristics in hospitalized patients with NCSE and CSE and compare their treatment and outcome. PATIENTS AND METHODS: The electroencephalographic recording records of adult patients with electrographic status epilepticus were retrieved. Patients' clinical records were then analyzed. RESULTS: Fifty-three patients with CSE and 25 patients with NCSE were identified. Background diseases, neuroimaging findings and complications were similar in CSE and NCSE. Anoxia was a more frequent etiological factor only for myoclonic SE. Patients with CSE presented more often with coma. The number of drugs used for treatment was similar, but anesthetics drugs were administered more frequently in patients with CSE. The 30-day mortality rate was higher in myoclonic SE and generalized tonic-clonic SE, but the outcome on discharge in terms of survival and recovery was comparable between CSE and NCSE. CONCLUSIONS: The results of the present study show that the clinical parameters of NCSE in acutely ill patients do not substantially differ from those of patients with CSE. Moreover, despite more severe mental changes and the need for more anesthetic drugs for treatment of CSE, the final outcome did not differ between both groups. This might indicate that NCSE in acutely ill patients should be regarded as seriously as CSE.

Utility of hospitalization following a first unprovoked seizure.

OBJECTIVES: Hospital admission in otherwise healthy patients following a first unprovoked seizure is controversial. We aimed to evaluate the influence of admission in a neurology department on the identification of risk factors for seizure recurrence in patients with a first unprovoked seizure. MATERIALS AND METHODS: We retrospectively reviewed the medical records of patients with a first unprovoked seizure, who were admitted to the neurology departments at two medical centers between 2007 and 2009. Risk factors for seizure recurrence included the following: abnormal neurological examination, abnormal brain CT scan, and epileptiform discharges on the EEG. RESULTS: The study group included 97 patients (52 men) aged 18-85 years (mean 42). Eighty-seven (90%) patients were admitted following a generalized tonic-clonic seizure. Risk factors were identified in the emergency room (ER) in 36 (37%) patients, mainly including abnormalities of the neurological examination and brain CT scan. Nineteen (20%) patients had a risk factor which was not apparent during ER evaluation, consisting of epileptiform activity on the EEG. Five (5%) patients had recurrent seizures during admission, three of them without risk factors during the ER evaluation. CONCLUSIONS: Risk factors for seizure recurrence were detected during admission in nearly a quarter of the patients who presented to the emergency room with a first unprovoked seizure. Because the main advantage of admission is the EEG recording, we suggest that an early EEG should be obtained in these patients either during admission or through a special accelerated outpatient arrangement.

Long-term video-EEG in patients with frontal seizures.

The interictal epileptiform discharge (IED) yield of long-term video-EEG (LTVEEG) monitoring is increased compared to a single out-patient EEG, but was not studied specifically in frontal lobe epilepsy. Since IED recording can influence the length of monitoring when seizures are not recorded during LTVEEG, we aimed to assess the IED yield of LTVEEG recording in patients with frontal seizures. We retrospectively reviewed the medical records of 20 patients with frontal seizures during non-invasive LTVEEG in Tel Aviv Medical Center between 2003 and 2008 and compared them with the results of out-patient EEG. The study group included 11 (55%) men and 9 women aged 15-82 years (mean: 27 years). LTVEEG duration ranged between 4 and 29 days (mean: 14 days). IEDs were detected by each of the tests in eight (40%) patients. We conclude that non-invasive LTVEEG and out-patient EEG have a similar diagnostic yield for IEDs in patients with frontal seizures. Therefore, seizures remain the most relevant clinical outcome of LTVEEG.

Outcome of lamotrigine treatment in juvenile myoclonic epilepsy.

OBJECTIVES: To determine the response rate of patients with juvenile myoclonic epilepsy (JME) to lamotrigine (LTG) and identify predictive factors for treatment response. MATERIAL AND METHODS: Medical records of 62 patients with JME were reviewed for demographic, clinical, and EEG parameters. We determined clinical response to LTG and compared LTG responders with non-responders. RESULTS: There were 35 LTG responders (56%) and 27 non-responders (44%). JME patients without generalized tonic clonic seizures (GTCS) responded better to LTG (P = 0.04). Valproic acid (VPA) failure because of adverse events rather than lack of efficacy (P = 0.069) and delay in diagnosis (P = 0.07) showed a tendency toward good response to LTG. CONCLUSIONS: LTG should be considered a drug of first choice for JME patients without GTCS. LTG as second-line treatment after VPA failure seems more appropriate for those patients whose reason for VPA failure is poor tolerability rather than lack of efficacy.

When should a sleep-deprived EEG be performed following a presumed first seizure in adults?

OBJECTIVES: To evaluate the effect of the interval between the seizure and the EEG recording on the yield of early sleep-deprived EEG (SD-EEG) in patients admitted following a presumed first seizure. MATERIALS AND METHODS: We retrospectively reviewed the EEG recordings and medical records of patients admitted to the Neurology Department in Assaf Harofeh Medical Center because of a presumed first seizure during a 3-year period between 2006 and 2009 and who had a SD-EEG following a first routine EEG without epileptiform discharges (EDs). RESULTS: The study group included 78 patients aged 18-78 years (mean 35 ± 17). Previous seizures were recognized through repeated history in 32 (41%) patients. EDs were recorded in the SD-EEG in 16 (21%) patients: 13/46 (28%) with a SD-EEG performed within 3 days following the seizure and 3/32 (9%) with a later SD-EEG (P = 0.042) and in 10/32 (31%) patients in whom previous seizures were recognized and 6/46 (13%) with a first seizure (P = 0.05). CONCLUSIONS: EDs in the SD-EEG following a first diagnosed seizure occur more commonly when the test is performed within 3 days following a first seizure or when previous seizures are recognized.

Epilepsy syndrome-associated balance dysfunction assessed by static posturography.

PURPOSE: To compare subclinical balance dysfunction in patients with various epilepsy syndromes with apparently healthy subjects. METHODS: Twenty-seven patients with localization-related epilepsy (LRE), 19 with primary generalized epilepsy (PGE), who had no subjective complaints of impaired balance and no abnormal neurologic findings on examination, and 22 apparently healthy subjects, underwent static posturography using the Posture Scale Analyzer (PSA) system. RESULTS: Sway index was higher in patients compared to healthy subjects in all tests, significant for single leg stance (p=0.005). Patients with PGE had a higher sway index compared to patients with LRE in six of the tests, also significant for single leg stance (p=0.027). This difference was not affected by the type of AED treatment or disease duration. CONCLUSION: Posturography can improve balance function assessment in patients with epilepsy, demonstrate subclinical impairment in seemingly asymptomatic patients, and further characterize balance deficits in different epilepsy syndromes.

Electroencephalography findings in adult patients with West Nile virus-associated meningitis and meningoencephalitis.

Eighteen adult patients with serologically confirmed West Nile virus (WNV)-associated meningitis or meningoencephalitis were admitted to our hospital during the 2000 West Nile fever outbreak in Israel. Thirteen of the patients had a more severe and prolonged clinical course, and an electroencephalogram (EEG) was, therefore, requested. A specific EEG pattern was seen in 8 patients, consisting of generalized slowing, which was more prominent over the anterior regions. Generalized slowing that was prominent over the temporal area was seen in 2 patients, and intermittent slowing over the temporal region was seen in 1 patient. Two patients had normal EEG findings. We suggest that WNV meningoencephalitis should be considered in the differential diagnosis of meningitis or meningoencephalitis with a prolonged clinical course and anteriorly predominant slowing on an EEG.

Periodic lateralized epileptiform discharges in multiple sclerosis: a case report.

The occurrence of epileptiform abnormalities on the EEG in patients with multiple sclerosis (MS) is rare. The following case correlates the clinical, EEG, MRI, and single photon emission computed tomographic (SPECT) findings in a patient with a long history of MS and acute onset of focal motor seizures and confusion. Two routine EEGs, brain MRI, and brain SPECT were performed. The patient was a 44-year-old woman with a long history of clinically definite MS of the relapsing-remitting and secondary progressive form with three events of focal motor seizures followed by generalized tonic-clonic seizures and postictal confusion. The first EEG done during admission showed periodic lateralized epileptiform discharges in the right temporal region. Brain MRI done several weeks later showed scattered T2 hyperintensities in several locations, including the periventricular and subcortical white matter bilaterally. Brain SPECT using Tc99-Neurolite demonstrated decreased perfusion on the right parietal and temporal lobes. This case suggests that focal motor seizures and a transient state of altered consciousness can be the result of an exacerbation of MS. The neurophysiologic expression of these clinical manifestations may present as periodic lateralized epileptiform discharges on the EEG and decreased regional perfusion on brain SPECT.

The clinical use of P300 event related potentials for the evaluation of cholinesterase inhibitors treatment in demented patients.

Centrally acting cholinesterase inhibitors (ChEIs) improve cognitive functions in Alzheimer's disease (AD) and other forms of dementia. Evaluation of treatment efficacy is based mainly on subjective assessment methods such as standardized neuropsychological tests. Therefore, an additional objective tool for the evaluation of drug response would be most helpful.Thirty-two patients suffering from dementia of several etiologies were treated with ChEIs (tacrine 19, donepezil 5, rivastigmine 8). Cognitive response was assessed pre ChEIs initiation (baseline) and after 26 weeks, as optimal tolerated doses were achieved and maintained (endpoint). Evaluation included repeated measurements of Mini Mental State Examination (MMSE), Alzheimer's disease assessment scale cognitive part (ADAS-cog) and P300. For statistical analysis we used ANOVA with repeated measures and Pearson correlation coefficient. Results demonstrated improvement of mean ADAS-cog by 2.0 points (from 29.4, n = 31 to 27.4, n = 29; p = 0.08) while MMSE remained almost unchanged (20.1, n = 29 to 19.8, n = 28). Mean P300 latency reduced significantly by 24 ms (from 383 +/- 7.9 msec, n = 32 to 359 +/- 7 msec, n = 32; p = 0.0001). However mean amplitudes did not change significantly from baseline to endpoint (13.5 +/- 6.2, n = 31 to 12.8 +/- 6.1, n = 31). Significant correlations were found between mean ADAS-cog and mean P300 latency at baseline and end-point (R = 0.485 p = 0.019, R = 0.626 p = 0.001 respectively, n = 23) and between mean MMSE and P300 latency at baseline and endpoint (R = -0.420 p = 0.046, R = -0.703 p < 0.001 respectively, n = 23). Our data suggests that P300 is a reliable instrument for assessment of cognitive response to ChEIs in demented patients.

Neurological features of West Nile virus infection during the 2000 outbreak in a regional hospital in Israel.

During the summer of 2000, 35 patients with West Nile Virus Fever were admitted to our hospital. Of these, the 26 (21 adults, mean age 56 (19-86) and 5 children (aged 9-15)) presented have neurological involvement, 33% with meningitis, 52% with meningoencephalitis, 10% with encephalitis and 5% with acute polyneuropathy. Presenting clinical features were fever in 95% of cases, headache in 90%, nausea/vomiting in 52%, confusion in 48%, somnolence in 38%, neck stiffness in 33%, a skin rash in 19%, diarrhea in 14%, cervical pain in 14%, seizure in 9%, photophobia in 9% and limb weakness in 4%. Leucopenia was not found. Two patients diagnosed with meningoencephalitis died. Three patients had signs of an acute polyneuropathy, this being the only complaint of one patient. The EEG was abnormal in all cases of meningitis or meningoencephalitis, except in three cases. Outbreaks of West Nile Virus Fever are emerging as a worldwide disease with high rates of neurological involvement and death. It should be considered in cases presenting with aseptic meningoencephalitis, meningitis and acute polyneuropathy, especially during the summer months and in areas along bird migration pathways.

Nerve conduction abnormalities in the arms of patients with arteriovenous fistula.

Fifteen patients with unilateral functioning arteriovenous fistula were assessed clinically and electromyographically to identify local neurologic changes. Ten of the patients were symptomatic (motor and/or sensory) and 5 were asymptomatic. Clinically, 11 patients had signs of a mild polyneuropathy, 2 patients of ulnar neuropathy, and 1 patient had signs of median neuropathy. A decrease of the above-elbow ulnar conduction velocity was noted in the study group on the side of the functional fistula, and in the symptomatic patients only on the side of the nonfunctional/nonexisting fistula. We suggest that ulnar nerve vulnerability should be taken into consideration during construction of the fistula, as well as during dialysis.