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Biomedical subjects

Gregory Krauss

Publications and source records attributed to Gregory Krauss.

9 recordsLinked to original sources
PubMed2006

Speech recognition impairments in patients with intractable right temporal lobe epilepsy.

PURPOSE: To evaluate speech recognition in patients with focal intractable epilepsy and surgical resections in the nondominant (right) hemisphere. METHODS: Speech recognition was tested prospectively, under different listening conditions, in 22 patients with right temporal lobe (11 patients) or extra-temporal lobe epilepsy. All were left-hemisphere dominant for language on preoperative intracarotid sodium amobarbital testing. RESULTS: All patients demonstrated normal auditory recognition of words and environmental sounds before and after surgery. However, when real-world listening conditions were simulated by using acoustically degraded (filtered) words, patients with temporal lobe epilepsy performed significantly worse than patients with frontal or parietooccipital lobe epilepsy before and after surgery (p<0.0001). CONCLUSIONS: Patients with intractable right temporal lobe epilepsy are at risk for speech recognition impairments in real-world listening environments, independent of surgery. The impact of speech recognition difficulties on verbal communication, coupled with the prevalence of adverse listening environments, underscores the importance of testing speech recognition under different listening conditions in patients with intractable right temporal lobe epilepsy.

Adolescent↗
PubMed2004

Mortality in epilepsy: driving fatalities vs other causes of death in patients with epilepsy.

OBJECTIVES: To estimate the risk to public safety posed by drivers with epilepsy, the authors compared annual totals and disease-specific risk for fatal crashes associated with seizures and other medical conditions. They compared individual risks for fatal crashes due to seizures and other causes of mortality in patients with epilepsy. METHODS: The authors analyzed Multiple-Cause of Mortality data files from death certificates provided by the National Center for Health Statistics (NCHS) for the years 1995-97. They analyzed International Classification of Diseases-9 codes for underlying causes of death and other major conditions and determined disease-specific rates of fatal crashes associated with seizures and other medical conditions. RESULTS: An average of 44,027 US drivers died annually as a result of motor vehicle crashes during 1995-97; however, only 86 (0.2%, range 82 to 97) of these deaths were associated with seizures in mortality reports. The incidence rate of fatal crashes for patients with seizures was 2.3 times the rate for patients with cardiovascular and hypertensive diseases and 4.6 times the rate for patients with diabetes. The proportionate mortality ratio for motor vehicle crashes in patients with seizures was low (0.2); most patients with epilepsy died of common cardiovascular and systemic disorders. CONCLUSION: Fatal driver crashes due to seizures are uncommon. This finding supports the current public policy of permitting patients whose seizures are controlled to drive.

Accidents, Traffic↗
PubMed2002

A prospective study of motor recovery following multiple subpial transections.

A prospective study of motor recovery was undertaken in a patient scheduled to undergo multiple subpial transections (MST) of right sensorimotor cortex. Pre-transection, functional MRI (fMRI) and cortical stimulation mapping confirmed left hand motor control within right primary motor cortex. Immediately post-transection, behavioral testing demonstrated preserved strength bilaterally but decreased dexterity in the left hand. Seven weeks post-transection, dexterity returned to normal and left hand finger tapping corresponded with multiple bilateral foci of fMRI activation. At 16 weeks, fMRI activation returned to pre-transection levels. These data indicate that cortical injury due to MST resulted in the temporary recruitment of distant cortical sites which presumably subserved normal motor function during recovery.

Adult↗
PubMed2002

Large-scale cortical displacement of a human retinotopic map.

The aim of the current study was to determine the retinotopic organization of a patient with congenital cortical dysgenesis and normal visual function. Using functional magnetic resonance imaging (fMRI), detailed retinotopic maps corresponding to the four visual field quadrants were projected onto cortical surfaces. Similar to control subjects, the upper right visual field mapped onto ventral left hemisphere and was retinotopically organized. The lower right visual field's cortical representation was also retinotopically organized, yet was displaced many centimeters anteriomedially. Moreover, the entire left visual field was represented in non-retinotopically organized islands in both hemispheres. These results indicate retinotopic maps can shift in both location and topography illustrating cortical reorganization presumably due to either cortical dysgenesis or functional displacement. NeuroReport

Adult↗
PubMed2002

Occurrence of psychosis in patients with epilepsy randomized to tiagabine or placebo treatment.

PURPOSE: Patients with drug-resistant epilepsy have a higher incidence of psychiatric problems and possibly greater intolerance to antiepileptic drugs (AEDs) than do other patients with epilepsy. Concern has been raised that gamma-aminobutyric acid (GABA)ergic drugs may be associated with treatment-emergent psychosis. Tiagabine (TGB; Gabitril), a new AED that blocks synaptic GABA uptake, was developed in trials of drug-resistant patients with epilepsy. We conducted ad hoc analyses of adverse events, drug intolerance, and treatment response to evaluate the association between TGB treatment and psychosis and whether psychiatric history might be predictive of tolerance or effectiveness of this GABAergic drug. METHODS: Data were analyzed from two multicenter, randomized, double-blind, placebo-controlled trials of add-on TGB therapy (32 or 56 mg daily) in 554 adolescents and adults with complex partial seizures (CPSs). After an 8- or 12-week baseline phase, double-blind treatment consisted of a 4-week titration period (with TGB dose gradually increased to 32 or 56 mg daily) and an 8- or 12-week fixed-dose period. Adverse events commonly associated with psychosis were evaluated. Treatment intolerance and effectiveness (> or =50% reduction in CPS rate) were compared among patients with and without psychiatric histories. RESULTS: Psychotic symptoms (hallucinations) were observed in three (0.8%) of 356 TGB-treated patients and none of 198 placebo-treated patients (p = 0.556, NS). Statistical analysis showed no interaction between psychiatric history and drug intolerance or treatment outcome. CONCLUSIONS: TGB administration appears to carry no significant increased risk of treatment-emergent psychosis. Psychiatric history was not predictive of the tolerance or effectiveness of the drug.

Adolescent↗
PubMed2002

Multiple subpial transection for intractable partial epilepsy: an international meta-analysis.

PURPOSE: Because the number and variety of patients at any single facility is not sufficient for clinical or statistical analysis, data from six major epilepsy centers that performed multiple subpial transections (MSTs) for medically intractable epilepsy were collected. METHODS: A meta-analysis was performed to elucidate the indications and outcome, and to assess the results of the procedure. Overall, 211 patients were represented with data regarding preoperative evaluation, procedures, seizure types and frequencies before and after surgery, postoperative deficits, and demographic information. Fifty-three patients underwent MST without resection. RESULTS: In patients with MST plus resection, excellent outcome (>95% reduction in seizure frequency) was obtained in 87% of patients for generalized seizures, 68% for complex partial seizures, and 68% for simple partial seizures. For the patients who underwent MST without resection, the rate of excellent outcome was only slightly lower, at 71% for generalized, 62% for complex partial, and 63% for simple partial seizures. EEG localization, age at epilepsy onset, duration of epilepsy, and location of MST were not significant predictors of outcome for any kinds of seizures after MST, with or without resection. New neurologic deficits were found in 47 patients overall, comparable in MST with resection (23%) or without (19%). CONCLUSIONS: These preliminary results suggest that MST has efficacy by itself, with minimal neurologic compromise, in cases in which resective surgery cannot be used to treat uncontrolled epilepsy. MST should be investigated as a stand-alone procedure to allow further development of criteria and predictive factors for outcome.

Epilepsies, Partial↗
PubMedDate not supplied

Current understanding of delayed anticonvulsant hypersensitivity reactions.

Hypersensitivity syndrome (HSS) reactions are one of the most feared idiosyncratic drug reactions and are most common with exposure to antiepileptic drugs (AEDs), sulfonamides, nonsteroidal antiinflammatory drugs, corticosteroids, and allopurinol. HSS is associated with chemotoxic and T-cell-mediated inflammatory injuries in barrier tissue systems that contain cytochrome oxidases (e.g., skin, mucosa, liver, and lungs) and can be seen as a derangement in the defense system against xenobiotics-bioactive foreign molecules. The mechanisms for anticonvulsant HSS are incompletely understood but involve genetic susceptibility, with accumulation of AEDs and oxidized metabolites causing major histocompatibility complex (MHC) and non-MHC-dependent clonal activation of T cells and subsequent cytokine/chemokine production in T cells, keratinocytes, and other target cells. This review discusses the classification and possible mechanisms for anticonvulsant HSS.

Journal Article↗