Semantically-triggered reading epilepsy: an experimental case study

Reading epilepsy today: A scoping review and meta-analysis of reports of the last three decades

BACKGROUND AND AIM

Reading-induced seizures are presumed to be rare phenomena attributed to an epilepsy syndrome not clearly belonging to either focal or generalized epilepsies. The aim of the article was to summarize knowledge and recent developments in the field of reading-induced seizures by reviewing all cases for which data were reported within the last three decades.

METHODS

A scoping systematic review of demographic, clinical, electroencephalography (EEG) and imaging data of cases with reading-induced seizures reported in PubMed and Web of Science between 1991-01-01 and 2022-08-21 and a meta-analysis of the findings.

RESULTS

The review included 101 case reports of epilepsy with reading-induced seizures (EwRIS) from 42 articles. The phenomenon was more prevalent among males (67, 66.3% vs. 34, 33.7%) with an average age of onset of 18.3 ± 7.9 years. When reported, 30.8% of patients had a family history of epilepsy. Orofacial reflex myocloni (ORM) were the most frequent manifestation (68, 67.3% cases), other presentations, mostly in addition to ORM, included visual, sensory or cognitive symptoms, non-orofacial myoclonic seizures, and absence seizures. Within the sample, 75 (74.3%) patients were identified as having primary reading epilepsy (PRE), 13 (12.9%) idiopathic generalised epilepsy (IGE) and 13 (12.9%) focal epilepsies. Advanced EEG and functional imaging data suggest that the basic mechanism of reading-induced seizures is probably similar despite different symptoms and consists of upregulation of the complex cerebral subsystem involved in reading. Ictogenesis and resulting symptomatology may then depend on predominant sensory or proprioceptive stimuli during reading.

CONCLUSION

In most cases, reading-induced seizures were confirmed to belong to a particular epilepsy syndrome of PRE. However, there were substantial subgroups with IGE and focal epilepsies. Most likely, reading-induced seizures occur as an abnormal response to extero- or proprioceptive input into an upregulated cortical network subserving reading. Most recent researchers consider EwRIS a system epilepsy.

Recruitment of the left precentral gyrus in reading epilepsy: A multimodal neuroimaging study

Purpose

In a previous study, we investigated a 42-year-old male patient with primary reading epilepsy using continuous video-electroencephalography (EEG). Reading tasks induced left parasagittal spikes with a higher spike frequency when the phonological reading pathway was recruited compared to the lexical one. Here, we seek to localize the epileptogenic focus in the same patient as a function of reading pathway using multimodal neuroimaging.

Methods and results

The participant read irregular words and nonwords presented in a block-design paradigm during magnetoencephalography (MEG), functional near-infrared spectroscopy (fNIRS), and functional magnetic resonance imaging (fMRI) recordings, all combined with EEG. Spike analyses from MEG, fNIRS, and fMRI–EEGs data revealed an epileptic focus in the left precentral gyrus, and spike localization did not differ in lexical and phonological reading.

Conclusion

This study is the first to investigate ictogenesis in reading epilepsy during both lexical and phonological reading while using three different multimodal neuroimaging techniques. The somatosensory and motor control functions of the left precentral gyrus that are congruently involved in lexical as well as phonological reading can explain the identical spike localization in both reading pathways. The concurrence between our findings in this study and those from our previous one supports the role of the left precentral gyrus in phonological output computation as well as seizure activity in a case of reading epilepsy.

EEG activation by neuropsychological tasks in idiopathic generalized epilepsy of adolescence

THE AIM OF THE STUDY

To evaluate the effects of neuropsychological activation (NPA) tasks on epileptiform discharges in adolescents with idiopathic generalized epilepsy (IGE) and their possible relationship to clinical epilepsy-related factors, also to compare the effects of the NPA to the habitual methods of electroencephalographic (EEG) activation.

METHODS/SUBJECTS

Fifty-nine patients with IGE aged 14-17 years underwent baseline video-EEG recording with habitual activation procedures followed by NPA tasks, and sleep EEG after sleep deprivation on the next day.

RESULTS

At least one task of NPA showed provocative effect in 18.6% of cases. There was no difference between the provocative effects of action-programming and thinking NPA task groups as well as among individual NPA tasks. The provocative effects of NPA tasks were more prevalent in photosensitive cases, especially the tasks of action-programming type (p=0.04). The provocative NPA effects showed no relationship to gender, age, age at seizure onset, duration of epilepsy, treatment status, presence of myoclonias, recent generalized tonic-clonic seizures, family history of epilepsy. The provocative effects of NPA were comparable to those of hyperventilation (23.7%) and intermittent light stimulation (30.5%) (p>0.05).

CONCLUSIONS

Although the provocative effects NPA tasks on epileptiform discharges on EEG did not outweigh the effects of the habitual activation procedures, NPA activation might be helpful as an additional diagnostic tool in adolescents with IGE in selected cases when routine EEG is not informative enough or when sleep EEG is readily unavailable, also in photosensitive cases. It may also help in providing advice for patients on safety issues.

Did Herbert Spencer have reading epilepsy?

Herbert Spencer, the nineteenth-century philosopher, has frequently been dismissed as a "fantastical hypochondriac" (as his most recent biographer, Mark Francis, terms him). Yet he left a record in his Autobiography of symptoms that suggest a very different diagnosis. Abruptly at age 35, he found that the activity of reading, previously indulged in without difficulty, triggered paroxysmal episodes of disturbing "head-sensations" including "giddiness" (so Spencer described them); these severely curtailed his ability to carry out his philosophical studies. Of all possible explanations for such episodes, none seems as likely as reading epilepsy. Enduring preconceptions about Spencer's presumed neurosesmay have kept modern historians from appreciating that Spencer suffered from a legitimate, if esoteric, neurological malady.

Reflex reading epilepsy: effect of linguistic characteristics on spike frequency

Reading epilepsy is a rare reflex epilepsy in which seizures are provoked by reading. Several cases have been described in the literature, but the pathophysiological processes vary widely and remain unclear. We describe a 42-year-old male patient with reading epilepsy evaluated using clinical assessments and continuous video/EEG recordings. We administered verbal, nonverbal, and reading tasks to determine factors precipitating seizures. Linguistic characteristics of the words were manipulated. Results indicated that reading-induced seizures were significantly more numerous than those observed during verbal and nonverbal tasks. In reading tasks, spike frequency significantly increased with involvement of the phonological reading route. Spikes were recorded predominantly in left parasagittal regions. Future cerebral imaging studies will enable us to visualize the spatial localization and temporal course of reading-induced seizures and brain activity involved in reading. A better understanding of reading epilepsy is crucial for reading rehabilitation in these patients.

Writing epilepsy: a neurophysiological, neuropsychological and neuroimaging study

Writing epilepsy is a rare reflex syndrome in which seizures are triggered by writing. We describe a 33-year-old, right-handed man, with a history of juvenile absence epilepsy in remission and a family history of epilepsy, in whom myoclonic jerks precipitated exclusively by writing started at the age of 30. Intensive video/EEG monitoring during neuropsychological tests revealed, at about 1 minute after starting to write, a dystonic posture, followed by myoclonic jerks involving the right hand that shortly after became generalized. Concomitantly, the ictal EEG documented generalized hypersynchronous polyspike-wave discharges, maximal over the right parietocentral area. SPECT revealed an ictal hyperperfusion and interictal hypoperfusion over right parietofrontal regions, and fMRI showed extensive and intense left frontal, supplementary motor area activation, induced by writing. This case study provides some evidence supporting the hypothesis that the mechanism underlying writing-triggered seizures may be a generalized seizure process, with a focal cortical trigger zone, presumed to be the left frontal lobe as suggested by clinical and fMRI data. A relevant role played by the right hemisphere (right parietofrontal region) is postulated in the full-blown expression of reflex epileptogenesis, as supported by EEG and SPECT findings.