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Biomedical subjects

S R Benbadis

Publications and source records attributed to S R Benbadis.

At least 19 recordsLinked to original sources
PubMed2000

Practice advisory.

Explore the source record for details and available documents.

Abstracting and Indexing↗
PubMed1999

Association between the Epworth sleepiness scale and the multiple sleep latency test in a clinical population.

BACKGROUND: Excessive daytime sleepiness can be evaluated with both subjective and objective tests. OBJECTIVE: To examine the association between Epworth Sleepiness Scale scores and sleep latency on the multiple sleep latency test. DESIGN: Case series. SETTING: Referral sleep disorders center. PATIENTS: 102 consecutive patients evaluated for excessive daytime sleepiness. MEASUREMENTS: Epworth Sleepiness Scale scores and mean sleep latency on the multiple sleep latency test. RESULTS: No significant association was seen between Epworth scores and mean sleep latency (Pearson correlation, -0.17 [95% CI, -0.35 to 0.03]; P = 0.09) (analysis of variance, P = 0.13). The mean Epworth score did not differ in three groups of patients who were defined by mean sleep latency as having normal sleep latency (>10 minutes), moderate sleep latency (5 to 10 minutes), or severe sleep latency (<5 minutes) (analysis of variance, P = 0.13). CONCLUSIONS: No statistically or clinically significant association was seen between Epworth scores and mean sleep latency. The subjective Epworth Sleepiness Scale and the objective multiple sleep latency test may evaluate different, complementary aspects of sleepiness.

Humans↗
PubMed1999

Observations on the misdiagnosis of generalized epilepsy as partial epilepsy: causes and consequences.

More therapeutic options (surgical and pharmacologic) are available for partial than for generalized epilepsies. This report describes and analyzes a possible bias to diagnose focal epilepsies. Data were prospectively collected on patients who underwent noninvasive prolonged EEG-video monitoring over a 2-year period at an epilepsy program. Cases where the diagnosis of 'partial seizures' (after monitoring) was questionable were identified and the data reviewed. Sixteen cases were identified. (a) Six had an idiopathic generalized epilepsy. All had generalized tonic-clonic (GTC) seizures, two had myoclonic seizures, and three had typical absences. All patients had generalized spikes and spike-wave complexes. All had normal IQs and normal brain imaging. One patient underwent invasive EEG. (b) Ten patients had a symptomatic or cryptogenic generalized epilepsy. IQs ranged from 49 to 74 (mean: 63). All patients had diffuse EEG slowing, and generalized ictal EEG patterns. Interictal EEG showed generalized spike-wave complexes in nine, and multifocal spikes in five. Seizures included GTC in all, generalized tonic in four, and atypical absences in two. Two of the 10 patients underwent invasive EEG. The misdiagnosis of generalized epilepsy as partial epilepsy occurs for both idiopathic and cryptogenic or symptomatic generalized epilepsies, more often in the latter case. Risk factors may include: asymmetry in EEG or seizure semeiology, the eagerness to enroll in drug studies or surgical programs, and the lack of team thinking involving several epileptologists. This problem is almost certainly under-reported and may occasionally result in unwarranted invasive procedures.

Adolescent↗
PubMed1998

Is speech arrest during wada testing a valid method for determining hemispheric representation of language?

BACKGROUND AND OBJECTIVE: The intracarotid amobarbital procedure, or Wada test, is the method of choice to determine hemispheric representation of language, and is routinely used in the presurgical evaluation for intractable epilepsy. Some investigators perform comprehensive language assessments, but others base language lateralization solely on speech arrest. This study sought to determine whether speech arrest alone during Wada testing provides valid data regarding language lateralization. METHODS: The subjects (previously reported) were 21 patients evaluated for intractable epilepsy, who underwent language lateralization by Wada testing and functional MRI (FMRI). For each patient, language representation was determined by calculating: (1) a Wada laterality index based exclusively on speech arrest; (2) a Wada laterality index based on comprehensive language assessment; and (3) an FMRI laterality quotient. Correlation coefficients and categorical classifications were analyzed. RESULTS: There was no significant correlation between the Wada laterality quotient derived from duration of speech arrest and either the comprehensive Wada language laterality score (r =.35, p =.12) or FMRI language laterality score (r =.32, p =.16). Categorical classification as left, right or bilateral language also showed marked discordance between speech arrest and the other two methods. CONCLUSION: Duration of speech arrest during Wada testing is not a valid measure of language dominance.

Amobarbital↗
PubMed1996

Tongue biting as a lateralizing sign in partial epilepsy.

Lateral tongue biting is associated with seizures. This analysis investigates lateral tongue biting as a lateralizing sing in partial seizures. Of 106 consecutively monitored patients, seven had partial epilepsy and sustained a tongue injury during a seizure. The relationship between the side of tongue injury and the hemisphere of seizure onset in these seven patients was analysed. The tongue injury was ipsilateral to the epileptogenic zone in 5 and contralateral in 2, for a predictive value of 71%. Lateral tongue biting may be a useful adjunctive lateralizing sign in partial seizures.

Brain Mapping↗
PubMed1996

Value of full-field visual evoked potentials for retrochiasmal lesions.

Some abnormalities in the P100 on monocular stimulation have been said to indicate retrochiasmal abnormalities. This study was undertaken to evaluate the reliability of visual evoked potentials (VEPs) for this purpose. We retrospectively reviewed VEPs that could be interpreted as indicative of a retrochiasmal lesion, based on an amplitude asymmetry of >50% between the P100 recorded on the left and right occipital regions. The abnormality had to be present on both left and right monocular stimulation (uncrossed pattern). Studies were conducted in accordance with the guidelines of the American Electroencephalographic Society. Findings on magnetic resonance (MR) imaging were analyzed. For comparison, we also studied a control group of 30 patients with normal VEPs. During a 16-month period, we identified 15 patients who fulfilled the aforementioned criteria and who had undergone an MR scan of the brain. Eight scans were normal and seven were abnormal. Of the seven abnormal scans, five revealed multiple periventricular white matter lesions in both hemispheres suggestive of multiple sclerosis: one a single punctate white matter lesion in the left frontal corona radiata, and one multiple white matter lesions in the basal ganglia, brainstem, and cerebellum but not in the hemispheres. In the control group with normal VEPs, nine had at least one hemispheric lesion on MR scans. This yielded a positive predictive value of 33%. The negative predictive value was 70%, sensitivity 36%, and specificity 68%. Because of a high rate of false positives, full-field VEPs were not reliable in predicting retrochiasmal lesions.

Evoked Potentials, Visual↗
PubMed1996

Unilateral blinking: a lateralizing sign in partial seizures.

BACKGROUND: Despite lateralizing signs, clinical lateralization of partial seizures may be difficult. We evaluated the usefulness of ictal unilateral blinking as a new lateralizing sign. METHODS: We retrospectively searched our seizure database over a 30-month period and collected videotapes of patients with ictal unilateral blinking. After initial review, we excluded patients in whom blinking was not clearly unilateral and those in whom it was accompanied by simultaneous facial clonic activity or mouth deviation. All patients underwent prolonged EEG-video monitoring. RESULTS: We identified 14 patients who met the above criteria, for a frequency of 1.5%. Age ranged from 18 months to 50 years (mean, 21.6). There were 11 males and 3 females. Unilateral blinking occurred 0 to 37 seconds (mean, 10) after clinical onset and was visible for 1 to 37 seconds (mean, 17). In 10 patients, other lateralizing signs were present. All patients had partial epilepsy, localized by surface EEG in 10 and by additional invasive EEG in four--nine were left hemisphere (four temporal, four frontal, one not further localized), three right hemisphere (two temporal, one frontal), and two undetermined. Of the 12 patients whose epileptogenic zone was lateralized, blinking was ipsilateral in 10 and contralateral in two. The predictive value of unilateral blinking was 83% against EEG localization. CONCLUSION: Unilateral blinking is a relatively uncommon but reliable lateralizing sign in partial seizures, usually indicating an ipsilateral epileptogenic zone.

Adolescent↗
PubMed1996

Photosensitive temporal lobe epilepsy.

Photic-induced seizures are usually generalized. There are several cases of focal seizures reported, and all have been shown to arise from the visual cortex. We report an unusual case of temporal lobe epilepsy, supported by electroclinical data and confirmed by a successful temporal lobectomy, with seizures induced by photic stimulation.

Adult↗