The Role of Dominant Premotor Cortex and Grapheme to Phoneme Transformation in Reading Epilepsy

Ritaccio, Anthony L.; Hickling, Edward J.; Ramani, Venkat

doi:10.1001/archneur.1992.00530330055016

Cited by 37 publications

(15 citation statements)

References 19 publications

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“…Lesions or subtle malformations of cortical development in the left premotor cortex have been described previously in cases of RE associated with PMJ (Ritaccio et al, 1992;Archer et al, 2003). Therefore, the present MSI study comes in strong support of both morphologic and EEGfMRI data, pointing to a major pathophysiologic role of Brodmann area 6 (premotor cortex and SMC) in the generation of PMJs in this epileptic disorder.…”

Section: Discussionsupporting

confidence: 88%

Supplementary motor cortex involvement in reading epilepsy revealed by magnetic source imaging

Beeck¹,

Legros

Gaspard

et al. 2011

Epilepsia

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SUMMARYReading epilepsy (RE) is an idiopathic reflex epilepsy syndrome characterized by perioral myoclonic jerks (PMJs) during reading associated with left-dominant frontotemporal spike-wave discharges (SWDs). To better understand the pathophysiology of this syndrome, we studied a 45-year-old patient using magnetic source imaging (MSI). The patient underwent two whole-head magnetoencephalography (MEG) recordings (Elekta Neuromag Oy) within 2 months while reading aloud. Forty-two SWDs associated with PMJs were recorded and averaged with respect to SWDs peak power. Epileptic discharges were then reconstructed using conventional equivalent current dipoles (ECDs) modeling, distributed sources sLORETA modeling, and beamformer approach. These methods identified two brain sources located in the left supplementary motor cortex (SMC) and the left primary sensorimotor face area (PSMFA). The spatiotemporal pattern of the sources was characterized by a cross-talk between these two brain regions, with an initial source in the left SMC. This MSI investigation suggests that RE-PMJs are associated with reading-induced activation of hyperexcitable neurons in the left SMC, followed by secondary propagation to the left PSMFA producing the myoclonus. KEY WORDS: Reading epilepsy, Reflex epilepsy, Magnetoencephalography, Magnetic source imaging, Supplementary motor cortex.Reading epilepsy (RE) is a rare idiopathic partial reflex epileptic syndrome characterized by two types of readinginduced seizures (Koutroumanidis et al., 1998;Gavaret et al., 2010;Koepp 2010;Maillard et al., 2010;Miller et al., 2010). The most common seizure type associates perioral myoclonic jerks (PMJs) with left-dominant frontotemporal spike-wave discharges (SWDs). The second seizure type associates visual symptoms and alexia or dyslexia with leftdominant temporooccipital SWDs.The pathophysiology of RE characterized by PMJs remains unclear. Combined electroencephalgraphy (EEG) and functional magnetic resonance imaging (EEG-fMRI) studies have found left-dominant activations of motor and premotor cortical areas, together with some subcortical structures, during reading-induced PMJs (Archer et al., 2003;Salek-Haddadi et al., 2009). Due to the relatively low temporal resolution of EEG-fMRI, these studies did not inform on the neuronal recruitment chronology within the identified network.To tackle this temporal dimension, we report a case of RE with PMJ studied with magnetic source imaging (MSI). MSI localizes noninvasively neuronal sources contributing to signals detected by magnetoencephalography (MEG), with a temporal resolution in the millisecond range and a spatial resolution of a few millimeters (Hämäläinen et al., 1993) Material and Methods Clinical dataA right-handed and Dutch-speaking 45-year-old woman, diagnosed with catatonic schizophrenia, was treated with quetiapine, an oral antipsychotic drug. A few months after quetiapine was started, right PMJs appeared while she was reading and led to two episodes of secondary tonic-clonic generalized seizures. Vide...

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Section: Discussionsupporting

confidence: 88%

Supplementary motor cortex involvement in reading epilepsy revealed by magnetic source imaging

Beeck¹,

Legros

Gaspard

et al. 2011

Epilepsia

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“…Agraphia with impaired phonology-to-orthography conversion is found after parietal (Hillis, 2008;Roeltgen, Sevush, & Heilman, 1983) and occasionally also after dominant posterior-inferior frontal infarcts (Hillis, Chang et al, 2004;Marien et al, 2001). Furthermore, functional imaging (Sugihara, Kaminaga, & Sugishita, 2006), developmental (Bitan et al, 2007;Booth et al, 2004) and stimulation studies (Lubrano, Roux, & Demonet, 2004), as well as clinical observations (Ritaccio, Hickling, & Ramani, 1992) showed that dominant premotor areas are strongly involved in phoneme-to-grapheme conversion during spelling and writing. Finally, poor performance on a silent rhyming task and a decreased digit span are consistent with the assumption that apraxia of speech may interfere with working memory tasks through an impairment of 'inner speech' processes (Waters, Rochon, & Caplan, 1992;Ziegler, 2008).…”

Section: Discussionmentioning

confidence: 97%

Apraxia of speech from a right frontal lesion

Benke

Bodner

Ziegler³

2011

Journal of Neurolinguistics

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“…In the jaw jerk variant, ictal EEG is characterised either by brief, bilateral, synchronous spikes and waves or by focal ictal modifications 1 4 6 8 11 14 17. In the posterior variant, ictal EEG is characterised by a left occipito-temporal rhythmic discharge as in our case 1 12.…”

Section: Discussionmentioning

confidence: 99%

Reading epilepsy from the dominant temporo-occipital region

Gavaret

Guedj

Koessler

et al. 2009

Journal of Neurology, Neurosurgery & Psychiatry

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Background Reading epilepsy is a rare form of epilepsy, classified among idiopathic, age-and localisation-related (partial) epilepsies as a reflex epilepsy syndrome. Seizures usually consist of myoclonic jerks restricted to the jaw. However, distinct ictal features including visual symptoms and paroxysmal a-or dyslexia are described in some patients. The anatomical substrate of ictogenesis in reading epilepsy remains poorly understood. Methods The authors report here the case of a primary reading epilepsy for which ictal semiology was characterised by visual symptoms and dyslexia, investigated by MRI, interictal high-resolution EEG and PET, ictal video-EEG and SPECT. Brain MRI was normal. Interictal high-resolution EEG was performed with 64 scalp channels, a realistic head model and different algorithms to solve the inverse problem. Results Interictal source localisations highlighted the left occipito-temporal junction. Interictal PET demonstrated bilateral occipito-temporal hypometabolism with leftsided predominance. Ictal EEG showed a rhythmic discharge in left temporo-parieto-occipital junction channels, with left occipito-temporal predominance. MRI fusion of the coregistered subtraction between ictal and interictal SPECT individualised relative hyperperfusion affecting (a) the left occipito-parietal junction area, (b) the left lateral middle and inferior temporal gyri and (c) the left inferior frontal area. Conclusion Besides reading-induced myoclonic jerks of the jaw, a second variant of reading epilepsy exists with clearly partial seizures manifested by visual symptoms and a-or dyslexia. These seizures originate from the occipito-temporal region of the dominant hemisphere, corresponding to the posterior part of the neural network that underlies the function of reading.

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The Role of Dominant Premotor Cortex and Grapheme to Phoneme Transformation in Reading Epilepsy

Cited by 37 publications

References 19 publications

Supplementary motor cortex involvement in reading epilepsy revealed by magnetic source imaging

Supplementary motor cortex involvement in reading epilepsy revealed by magnetic source imaging

Apraxia of speech from a right frontal lesion

Reading epilepsy from the dominant temporo-occipital region

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