Reading-induced absence seizures

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.

Bitemporal form of partial reading epilepsy: further evidence for an idiopathic localization-related syndrome

Idiopathic partial reading epilepsy (RE) is a rare syndrome. We report the clinical and electroencephalographic characteristics of two right-handed patients with the following: reading-induced independent bilateral temporal lobe seizures, accompanied by alexia in left (dominant) sided seizures recorded on video-EEG (electroencephalography); subclinical activation over left posterior temporal and occipital electrodes during reading; no spontaneous seizure and no other trigger than reading; onset in adolescence; and history of varying resistance to treatment. Bilateral independent temporal lobe reflex seizures are part of the clinical spectrum of RE. It may result from hyperexcitability of bilateral cortical networks involved in the early steps of the reading process.

Cognition-induced epilepsy

Cognition-induced epilepsy comprises a group of loosely tied syndromes characterized by seizures regularly precipitated by cognitive tasks. Linguistic operations (e.g., reading, writing) and decision making associated with visuospatial manipulation are the most frequent and best-characterized triggers. The syndromes reviewed have a high degree of overlap and clinical/EEG variability, suggesting that any of the neural networks subserving these complex tasks may promote seizures on either a topographic basis or a functional/connective basis. Treatment options include typical pharmacological and surgical interventions as well as stimulus alteration, threshold alteration, and avoidance conditioning. We postulate that more commonly encountered epilepsy syndromes also have complex triggers.

New insights into the clinical management of partial epilepsies

The diagnosis, treatment, and prognosis of seizure disorders depend on the correct identification of epileptic syndromes. Partial epilepsies are heterogeneous and can be divided into idiopathic, cryptogenic, and symptomatic epilepsies. The most common of the idiopathic localization-related epilepsies is benign epilepsy with rolandic or centrotemporal spikes (BECTS). Seizures remain rare and the use of antiepileptic drug (AED) treatment in all patients does not appear justified. Children who present with some of the electroclinical characteristics of BECTS may also display severe unusual neurologic, neuropsychological, or atypical symptoms. In some cases, carbamazepine has been implicated as a triggering factor. Primary reading epilepsy and idiopathic occipital lobe epilepsies with photosensitivity are examples of an overlap between idiopathic localization-related and generalized epilepsies and respond well to sodium valproate. Autosomal dominant nocturnal frontal lobe epilepsy and benign familial infantile convulsions are recently described syndromes, differing in several ways from classical idiopathic localization-related epileptic syndromes. In cryptogenic or symptomatic epilepsy, the topography of the epileptogenic zone might influence drug efficacy. An individualized approach to AED selection, tailored to each patient's needs, should be used. Resistance of seizures to antiepileptic therapy may be due to diagnostic and/or treatment error or may be the result of noncompliance. Increasing the dosage, discontinuation or replacement of a drug, or addition of a second drug is indicated in truly resistant cases. The use of more than two AEDs rarely optimizes seizure control, and in some cases reduction of treatment may improve seizure control while lessening side effects. EEG-video assessment of patients with refractory epilepsy is important. Indications for and timing of epilepsy surgery should be reconsidered. Surgical therapy should probably be used more often and earlier than it is at present.