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Biomedical subjects

B J Steinhoff

Publications and source records attributed to B J Steinhoff.

61 records · Page 4Linked to original sources

Transcranial magnetic stimulation (TMS) of the brain in patients with mesiotemporal epileptic foci.

Transcranial magnetic stimulation (TMS) of the human brain is mainly used for the diagnosis of diseases with disturbed central motor conduction. Recent studies revealed controversial results concerning the possibility of a TMS-induced specific activation of epileptogenic foci in patients with localization-related epilepsies, which would make TMS an additional diagnostic tool for the presurgical localization of the primary epileptogenic zone. We applied TMS to 19 patients with complex-partial seizures and investigated its effects and safety. In 12 patients we performed TMS during scalp electroencephalogram (EEG) recordings. The remaining 7 patients with localization-related epilepsies of mesiobasal limbic seizure origin underwent EEG with additionally implanted foramen-ovale-electrodes (FOE). We did not notice any significant spike activation and even observed bilateral reduction of epileptic activity in some patients. On the contrary, hyperventilation induced a marked activation of the epileptic focus. Our findings support that TMS is safe since adverse effects did not occur. However, due to possible safety hazards, TMS in epileptic patients still requires cautious application until more data will be available.

Anticonvulsants↗

[Chronic bromide intoxication caused by bromide-containing combination drugs].

A 49-year-old woman who had noted increasing fatigue and found it difficult to concentrate became confused and uncoordinated with rapid speech. Anxious and suffering from insomnia she had for 6 weeks taken a prescription-free bromide-containing drug mixture (daily 0.09 g potassium bromide and 1.8 g sodium bromide), to a total bromide intake of 60 g. The admission diagnosis of chronic bromism was confirmed by a markedly increased serum bromide concentration (325 mg/l). Once she had stopped taking the drug and had increased her salt intake she became symptom-free within 8 days. The case demonstrates that, while chronic bromism has become rare, it should still be included in the differential diagnosis, even after intake of supposedly harmless medication.

Bromides↗

Hyponatremic coma under oxcarbazepine therapy.

Oxcarbazepine (OXC) is considered to be a promising new antiepileptic drug with similar efficacy and better tolerability compared to carbamazepine (CBZ). However, hyponatremia is supposed to occur even more often than with CBZ. We report on a patient who developed hyponatremic coma under OXC with a serum sodium level of 115 mmol/l, the second published case of OXC-induced hyponatremia with serious clinical adverse effects.

Anticonvulsants↗

Bromide treatment of pharmaco-resistant epilepsies with generalized tonic-clonic seizures: a clinical study.

In a retrospective controlled clinical study we investigated the efficacy of bromides (BR) as to the frequency of generalized tonic-clonic seizures (GTCS) as a monotherapy (n = 5) or combined with other antiepileptic drugs (AEDs) (n = 55), and compared the results statistically with those achieved with a treatment based on phenobarbitone (PB) and/or phenytoin (PHT) in a very similar group of another 60 patients. All patients treated with BR had previously proved to be pharmaco-resistant. In most of the cases the epilepsies were based on early cerebral lesions, and were partly associated with severe mental and physical handicaps. Most of the patients were between three and 14 years old. The percentage of responders was 58%, which means a reduction in the GTCS-frequency of more than 50%. The positive result was observed for 28 months on the average. 27% of all patients became free of GTCS for 18 months on the average (range, 44 days to 62 months), and 32% were improved (reduction in GTCS-frequency of more than 50% while not GTCS-free) for nearly three years on the average (range, 79 days to 110 months). Compared to PHT or PB, BR were slightly more efficient and similarly tolerable, but no statistically significant difference was seen (48% responders in the control group versus 58% responders in the BR-group). Thus, the statistical correlation with competitive therapies confirmed the good efficacy of BR against GTCS, which was previously demonstrated by clinical tests without control studies. We recommended BR in the case of every pharmaco-resistant epilepsy with GTCS as a therapeutic alternative.

Adolescent↗

EEG spike detection with a Kohonen feature map.

Artificial neural networks are widely used for pattern recognition tasks. For spike detection in electroencephalography (EEG), feedforward networks trained by the backpropagation algorithm are preferred by most authors. Opposed to this, we examined the off-line spike detection abilities of a Kohonen feature map (KFM), which is different from feedforward networks in certain aspects. The EEG data for the training set were obtained from patients with intractable partial epilepsies of mesiotemporal (n=2) or extratemporal (n=2) origin. For each patient the training set for the KFM included the same patterns of background activity and artifacts as well as the typical individual spike patterns. Three different-sized networks were examined (15 x 15 cells, 25 x 25 cells, and 60 x 60 cells in the Kohonen layer). To investigate the quality of spike detection the results obtained with the KFM were compared with the findings of two board-certified electroencephalographers. Application of a threshold based on the partial invariance of spike recognition against translation of the EEG provided an average sensitivity and selectivity of 80.2% at crossover threshold (71%-86%) depending on the networksize and noise. Multichannel EEG processing in real time will be available soon. In conclusion, pattern-based automated spike detection with a KFM is a promising approach in clinical epileptology and seems to be at least as accurate as other more-established methods of spike detection.

Adult↗