Neurophysiological mechanisms of aphasia in epilepsy

Mel'nichuk, P V; Зенков, Л Р; Morozov, Alexei A.; Коган, Е. А.; Aver'ianov, Iu N

doi:10.1007/bf01191584

Cited by 5 publications

(3 citation statements)

References 6 publications

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“…Abnormal AERs in more than half of our patients are in‐line with previous EEG works. The giant AERs (spikes) in 18% of our patients and earlier reports (Paty & Morault, 1984; Melnichuk et al., 1990; Paetau, 1994) suggest an interesting new pathogenetic theory for LKS. Enlarged responses to sounds (identical to the epileptic spikes) could be the consequence of cortical reorganization, for example, formation of mutual excitatory connections between pyramidal cells that have been denervated by their thalamocortical afferents (see e.g., Jacobs et al., 1999).…”

Section: Discussionsupporting

confidence: 73%

Magnetoencephalography in Landau‐Kleffner syndrome

Paetau

2009

Epilepsia

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SUMMARYMagnetoencephalography (MEG) detects weak magnetic fields outside the head. Spikes generated on the perisylvian convexity are detected only by electroencephalography (EEG), whereas spikes with intrasylvian generators are selectively seen by MEG. Generators of MEG and EEG spikes are determined using equivalent current dipoles (ECDs) that represent local cortical activity in parallel pyramidal neurons. MEG localizes cortical spike generators with a 1-2-cm spatial accuracy, and with a millisecond time resolution. This allows tracking of neural activity over successive synaptic connections in the cortical network. Both EEG and MEG are necessary for comprehensive spatial and temporal description of perisylvian epileptic networks in the Landau-Kleffner syndrome (LKS). MEG studies suggest that in more than 80% of LKS patients, the bilateral epileptic discharges are generated in the auditory-and language-related perisylvian cortex. Approximately 20% of children with LKS children have a unilateral perisylvian pacemaker that triggers secondary bilateral synchrony of spikes. This 20% may regain considerable language skills after multiple subpial transections (MSTs) of the pacemaker area. Outcome data of a few surgery patients suggest an indispensable role of MEG when planning the most efficient therapy for patients with LKS.

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Section: Discussionsupporting

confidence: 73%

Magnetoencephalography in Landau‐Kleffner syndrome

Paetau

2009

Epilepsia

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“…So, we admit that the aphasia occurred due to a compromise of regions specialized in language because of repeated localized epileptic seizures, precipitated and aggravated by the metabolic dysfunction 7,8,21 . It had persisted for two days after the seizures control, like a Todd's phenomenon, prolonged because of the unfavorable metabolic local environment.…”

Section: Discussionmentioning

confidence: 96%

Complex partial seizures and aphasia as initial manifestations of non-ketotic hyperglycemia: case report

Batista

Silva

Ferraz

et al. 1998

Arq. Neuro-Psiquiatr.

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-We describe a case of non-ketotic hyperglycemia (NKH), heralded by complex partial seizures and aphasia of epileptic origin, besides versive and partial motor seizures. This clinical picture was accompanied by left fronto-temporal spikes in the EEG. The seizures were controlled by carbamazepine only after the control of the diabetes. A month later, carbamazepine was discontinued. The patient remained without seizures, with normal language, using only glybenclamide. Complex partial seizures, opposed to simple partial seizures, are rarely described in association to NKH. Epileptic activity localized over language regions can manifest as aphasia.KEY WORDS: aphasia, seizures, diabetes mellitus. Crises parciais complexas e afasia como manifestações iniciais de hiperglicemia não cetótica: relato de casoRESUMO -Descrevemos um caso de hiperglicemia não-cetótica (HNC) cujas manifestações iniciais foram crises parciais complexas e afasia de origem epiléptica, além de crises versivas e parcias motoras. Este quadro clínico foi acompanhado por atividade epileptiforme na região fronto-temporal esquerda ao eletrencefalograma. As crises epilépticas foram controladas com carbamazepina (CBZ) apenas após o controle do diabetes mellitus. Após um mês, a CBZ foi suspensa, permanecendo a paciente com linguagem normal, sem novas crises epilépticas, em uso apenas de glibenclamida. Crises parciais complexas, ao contrário de crises parciais simples, são raramente descritas como manifestação de HNC. Atividade epileptiforme nas regiões relacionadas a linguagem podem manifestar-se como afasia. PALAVRAS-CHAVE: epilepsia, crises epilépticas, diabetes mellitus, afasia.Non-ketotic hyperglycemia (NKH) is classically associated to simple partial seizures and partial motor status epilepticus (SE) and rarely to complex partial seizures (CPS) 1,2 . We present a case that was heralded by CPS and aphasia of epileptic origin, before systemic signs and symptoms of diabetic decompensation. CASE REPORTA 60 year old black woman, right-handed, was brought by relatives to the neurological emergency room because of altered behaviour for a week. She presented irritation and moments of staring, that seemed to "turn off", stopping domestic work. At other times, she stopped speaking, or forgot the names of her relatives and objects, answering only monosyllables. Besides these episodes, she looked completely well. The patient and relatives denied other neurologic and systemic complaints, including fever, polyphagia, polydipsia, polyuria and Escola Paulista

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“…Almost all studies investigating the auditory system observed a normal functioning at least up to the level of the thalamus (Paetau et al., 1991). One investigation of the auditory and visual system in four LKS children with generalized CSWS predominant over the left temporal region, found that high‐amplitude spikes generated within the temporal region altered the late, not only auditory but also visual evoked potentials (Mel’nichuk et al., 1990). These findings were discussed within Luria’s conception of the integrative role of the temporal cortex essential to the understanding of speech: “the convergence of auditory, visual, and modally non specific afferentation in the temporal cortex play[s] an important role in the understanding of speech” (Luria, 1966).…”

Section: Neurophysiologic Investigations Of Auditory Dysfunction In Tmentioning

confidence: 99%

The assessment of auditory function in CSWS: Lessons from long‐term outcome

Metz‐Lutz

2009

Epilepsia

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SUMMARYIn Landau-Kleffner syndrome (LKS), the prominent and often first symptom is auditory verbal agnosia, which may affect nonverbal sounds. It was early suggested that the subsequent decline of speech expression might result from defective auditory analysis of the patient's own speech. Indeed, despite normal hearing levels, the children behave as if they were deaf, and very rapidly speech expression deteriorates and leads to the receptive aphasia typical of LKS. The association of auditory agnosia more or less restricted to speech with severe language decay prompted numerous studies aimed at specifying the defect in auditory processing and its pathophysiology.Long-term follow-up studies have addressed the issue of the outcome of verbal auditory processing and the development of verbal working memory capacities following the deprivation of phonologic input during the critical period of language development. Based on a review of neurophysiologic and neuropsychological studies of auditory and phonologic disorders published these last 20 years, we discuss the association of verbal agnosia and speech production decay, and try to explain the phonologic working memory deficit in the late outcome of LKS within the Hickok and Poeppel dual-stream model of speech processing.

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Neurophysiological mechanisms of aphasia in epilepsy

Cited by 5 publications

References 6 publications

Magnetoencephalography in Landau‐Kleffner syndrome

Magnetoencephalography in Landau‐Kleffner syndrome

Complex partial seizures and aphasia as initial manifestations of non-ketotic hyperglycemia: case report

The assessment of auditory function in CSWS: Lessons from long‐term outcome

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