Four-Way Wada: SEEG-based mapping with electrical stimulation, high frequency activity, and phase amplitude coupling to complement traditional Wada and functional MRI prior to epilepsy surgery.

Presurgical evaluation of refractory epilepsy involves functional investigations to minimize postoperative deficit. Assessing language and memory is conventionally undertaken using Wada and fMRI, and occasionally supplemented by data from invasive intracranial electroencephalography, such as electrical stimulation, corticortical evoked potentials, mapping of high frequency activity and phase amplitude coupling. We describe the comparative and complementary role of these methods to inform surgical decision-making and functional prognostication. We used Wada paradigm to standardize testing across all modalities. Postoperative neuropsychological testing confirmed deficit predicted based on these methods.

Longitudinal neurodevelopmental profile of a pediatric patient with de novo SPTAN1, epilepsy, and left hippocampal sclerosis.

Pathogenic variants in SPTAN1 result in abnormal neurodevelopment but limited information is available on the spectrum of neurodevelopmental profiles associated with variations in this gene. We present novel data collected at two time points over a three-year period in a nine-year-old patient with heterozygous de novo SPTAN1 variant, drug-resistant epilepsy, and left hippocampal sclerosis. Across evaluations, our patient's performance was highly variable, ranging from below age expectation to within age-expected range. The patient exhibited relative cognitive strengths at both time points on verbal-expressive tasks. Weaknesses were seen in her attention, executive function, psychomotor processing speed, fine motor, visual-motor integration, and social skills. Memory findings were consistent those associated with left hippocampal sclerosis. Evaluations resulted in diagnoses including attention deficit hyperactivity disorder and autism spectrum disorder.

Processing of rapid auditory stimuli in school-age children referred for evaluation of learning disorders.

Tallal hypothesized that reading disabled children have a domain-general deficit in processing rapidly occurring auditory stimuli that degrades speech perception, thereby limiting phonologic awareness and thus reading acquisition. She predicted they would be disproportionately affected by rapidly presented auditory stimuli. In this study, one hundred 7- to 11-year-old children with learning impairment (LI) and 243 non-learning impaired (NLI) children were evaluated on a two-tone auditory discrimination paradigm. LI committed more errors, but effects of timing were comparable. The same result was obtained for a subsample of good and poor readers. Task performance predicted reading, spelling, and calculation. Neural processes underlying perception of speech and other auditory stimuli may be less effective in poor readers; however, contrary to Tallal's hypothesis, rate may not be specifically affected.

Neural bases and development of face recognition in autism.

This paper critically examines the literature on face recognition in autism, including a discussion of the neural correlates of this ability. The authors begin by selectively reviewing the behavioral and cognitive neuroscience research on whether faces are represented by a "special" behavioral and neural system-one distinct from object processing. The authors then offer a neuroconstructivist model that attempts to account for the robust finding that certain regions in the inferior temporal cortex are recruited in the service of face recognition. This is followed by a review of the evidence supporting the view that face recognition is atypical in individuals with autism. This face-recognition deficit may indicate a continued risk for the further development of social impairments. The authors conclude by speculating on the role of experience in contributing to this atypical developmental pattern and its implications for normal development of face processing.

Diminished motor timing control in children referred for diagnosis of learning problems.

Disabled readers exhibit motor timing control (MTC) deficits in bimanual coordination relative to average readers. This article evaluates to what extent poor MTC is specific to reading or if it is related to learning problems in general. Children (7 to 11 years of age) referred for learning impairment (LI; n = 100) and same-age children nonlearning impaired (NLI; n = 243) performed a paced finger-tapping task. Greater variability of interresponse intervals was associated with poorer reading, spelling, and arithmetic achievement. The LI group performed more poorly than the NLI group, a difference that persisted even after adjusting for reading skill. Poor MTC is associated with poor reading but may also be a characteristic of children referred for learning problems, possibly signaling increased vulnerability of underlying neural integrative processes relevant to the child's adaptation to academic demands, including reading.

Speed of information processing in children referred for learning problems: performance on a visual filtering test.

Children referred for evaluation of learning impairment (LI, N =100) and a comparison group of nonreferred (NLI, N = 243) children were evaluated on a visual filtering task. The task was designed hierarchically to provide for evaluation of component operations-serial search, parallel search, decision, and response. With each additional processing demand, response times increased disproportionately for the LI group relative to the NLI group. Overall response time reliably predicted academic skills and cognitive ability, but was more strongly related to group membership. Thus, this nonverbal visual task is sensitive to a characteristic of children with learning problems over and above discrete academic and cognitive skills. Children with problems adapting to the demands of schooling may be distinguished by a disproportionate vulnerability to processing load.

Phonemic restoration and integration during dichotic listening.

In a series of experiments, evidence was obtained for phonemic restoration when a word with the segment /s/ excised and replaced by silence and a comparable noise segment were presented dichotically. What has been called phonemic integration was also demonstrated by presenting the excised /s/ and the word with the /s/ removed and replaced by silence dichotically. Phonemic restoration and integration effects tended to be enhanced when barely audible versions of the excised /s/ or noise segment replaced the silence. Finally, phonemic integration was obtained when words with an excised CV syllable or VC rime were present dichotically together with the remainder of the word.

Pseudoseizures: diagnostic evaluation.

A prospective study of pseudoseizures using prolonged video-electroencephalographic (EEG) recording was carried out in 60 patients. Of 33 patients with episodes of uncertain mechanism, a diagnosis based on recorded episodes was made in 18 (55%). Twelve (36%) had pseudoseizures; 6 (18%) had epileptic seizures. Ten additional patients had epileptiform EEGs compatible with epilepsy. Of 27 patients with presumably uncontrolled epileptic seizures, 4 (15%) had recorded pseudoseizures. Prediction of the nature of the episode by the admitting neurologist was accurate in 67% of cases. Determination from observations of unit personnel and neurologists was correct in less than 80% of episodes. These data suggest that pseudoseizures occur frequently in patients being evaluated for epilepsy or suspected epilepsy. The clinical differentiation between epileptic seizures and pseudoseizures is often inaccurate. This differentiation is facilitated by prolonged video-EEG recording.

Acute effects of phenytoin on peripheral nerve function in the rat.

The acute effect of intraperitoneal injection of phenytoin on rat peripheral nerve was studied. Conduction velocities in the ventral caudal nerve were measured hourly and phenytoin blood levels were obtained 4 to 5 hours after injection. Conduction velocity decreased by 23% in the 25 phenytoin-treated animals from a control value of 30.0 plus or minus 1.3m/sec (mean plus or minus SEM) to a 4-hour value of 23.0 plus or minus 1.3 m/sec (P less than 0.001). The phenytoin blood level 4 hours after injection was 45.0 plus or minus 1.3 micrograms/ml. Amplitudes of evoked muscle action potentials in the treated group decreased by 37% from control values. High levels of phenytoin induce prompt slowing of nerve conduction velocity within hours, which may be mediated by mechanisms similar to those responsible for toxic central effects.