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Biomedical subjects

W T Seidel

Publications and source records attributed to W T Seidel.

7 recordsLinked to original sources
PubMed2003

Temporal lobe stimulation reveals anatomic distinction between auditory naming processes.

BACKGROUND: Language errors induced by cortical stimulation can provide insight into function(s) supported by the area stimulated. The authors observed that some stimulation-induced errors during auditory description naming were characterized by tip-of-the-tongue responses or paraphasic errors, suggesting expressive difficulty, whereas others were qualitatively different, suggesting receptive difficulty. They hypothesized that these two response types reflected disruption at different stages of auditory verbal processing and that these "subprocesses" might be supported by anatomically distinct cortical areas. OBJECTIVE: To explore the topographic distribution of error types in auditory verbal processing. METHODS: Twenty-one patients requiring left temporal lobe surgery underwent preresection language mapping using direct cortical stimulation. Auditory naming was tested at temporal sites extending from 1 cm from the anterior tip to the parietal operculum. Errors were dichotomized as either "expressive" or "receptive." The topographic distribution of error types was explored. RESULTS: Sites associated with the two error types were topographically distinct from one another. Most receptive sites were located in the middle portion of the superior temporal gyrus (STG), whereas most expressive sites fell outside this region, scattered along lateral temporal and temporoparietal cortex. CONCLUSIONS: Results raise clinical questions regarding the inclusion of the STG in temporal lobe epilepsy surgery and suggest that more detailed cortical mapping might enable better prediction of postoperative language decline. From a theoretical perspective, results carry implications regarding the understanding of structure-function relations underlying temporal lobe mediation of auditory language processing.

Acoustic Stimulation↗
PubMed2001

Experience with the ketogenic diet in infants.

OBJECTIVE: To evaluate the effectiveness, tolerability, and adverse effects of the ketogenic diet in infants with refractory epilepsy. METHODS: A retrospective review of 32 infants who had been treated with the ketogenic diet at a large metropolitan institution. RESULTS: Most infants (71%) were able to maintain strong ketosis. The overall effectiveness of the diet in infants was similar to that reported in the literature for older children; 19.4% became seizure-free, and an additional 35.5% had >50% reduction in seizure frequency. The diet was particularly effective for patients with infantile spasms/myoclonic seizures. There were concomitant reductions in antiepileptic medications. The majority of parents reported improvements in seizure frequency and in their child's behavior and function, particularly with respect to attention/alertness, activity level, and socialization. The diet generally was well-tolerated, and 96.4% maintained appropriate growth parameters. Adverse events, all reversible and occurring in one patient each, included renal stone, gastritis, ulcerative colitis, alteration of mentation, and hyperlipidemia. CONCLUSION: The ketogenic diet should be considered safe and effective treatment for infants with intractable seizures.

Diet Therapy↗
PubMed1999

Cognitive and behavioral effects of carbamazepine in children: data from benign rolandic epilepsy.

The effects of antiepileptic drugs on cognition are difficult to delineate, yet of critical importance for children with epilepsy. We investigated the cognitive and behavioral effects of carbamazepine in children with benign rolandic epilepsy. Ten subjects with benign rolandic epilepsy were evaluated with and without carbamazepine treatment. Fourteen unmedicated subjects with migraine headache evaluated twice served as a control group. Subjects were 6 to 12 years of age, fluent in English, and not mentally retarded. We found that children with benign rolandic epilepsy were quicker on a visual-search task and recalled stories better when not treated than when treated with carbamazepine. After correction for multiple comparisons only the memory finding remained significant. Higher carbamazepine serum level was associated with slower performance on the same visual-search task. This latter finding did not meet multiple comparison criteria. Numerous significant practice effects were found within the control group. Comparisons with reliable change indices identified two subjects with benign rolandic epilepsy with particularly poor scores while receiving carbamazepine. These findings suggest some effects on memory from carbamazepine; however, they do not support meaningful dosage-related effects, within the recommended range. Significant practice effects confirmed the need to control for such effects when evaluating treatments. Finally, identification of two subjects who performed more poorly while on carbamazepine suggests that some children might experience particular difficulties while receiving this medication and highlights the need to investigate individual subject responses to treatment.

Analysis of Variance↗
PubMed1990

Evidence of difficulties in sustained attention in children with ADDH.

It has been suggested that children with ADDH have specific difficulties in sustained attention. Despite some early studies supporting this position, many recent reports using continuous performance tests (CPTs) have failed to confirm this hypothesis. Possible reasons for this discrepancy are outlined and an attempt to corroborate and extend an earlier study (Sykes, Douglas, & Morgenstern, 1973) was undertaken. CPT results in normal children indicated that changes in performance over time, although not affected by gender, were influenced by age. Data from ADDH subjects indicated that they performed significantly more poorly with time on task than did controls. These results suggest that the ability to sustain attention increases with age and does not vary by gender. Furthermore, difficultues in the ability to sustain attention can be demonstrated in children with ADDH. Finally, it is suggested that within-age-level comparisons between groups of ADDH and controls would be more clinically sensitive than across-age-group comparisons.

Attention↗
PubMed1989

The independence of hyperactivity from conduct disorder: methodological considerations.

It has been claimed that the childhood behavioural factors "hyperactivity" and "conduct disorder" are highly correlated. The fact that hyperactive symptoms load heavily on the conduct disorder factor has also been used to support the notion that hyperactivity is not an independent behavioural dimension. The present study employs a large sample of combined clinic and normal children to demonstrate that both of these observations are artifacts of methodological technique. When factor score coefficients are used to interpret factors, the hyperactive symptoms do not load on the conduct disorder factor. If factor scores are defined by the use of unit weights, as in previous studies, then the intercorrelation between the hyperactive and conduct disorder factors is high. The use of factor score coefficients to define factors, on the other hand, produces uncorrelated factors. The results support the idea that hyperactivity and conduct disorder are independent behavioural dimensions.

Adolescent↗
PubMed1986

Relations between amygdaloid and anterior neocortical kindling.

Primary kindling of generalized seizures with amygdaloid stimulation facilitated the subsequent kindling of generalized seizures with neocortical stimulation. Similarly, initial kindling of generalized seizures with anterior neocortical stimulation facilitated the kindling of generalized amygdaloid seizures. Unexpectedly, there were striking differences in the reliability with which seizures could be triggered by amygdaloid and neocortical stimulation. The results support the idea that there is a single mechanism that is responsible for seizure generalization.

Amygdala↗