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  • Updated 06.28.2023
  • Released 04.26.2001
  • Expires For CME 06.28.2026

Epilepsy with reading-induced seizures

Introduction

Overview

Epilepsy with reading-induced seizures is a rare form of reflex epilepsy in which all, or almost all, seizures are precipitated by reading. There are two variants: the most common manifests with jaw myoclonus (myoclonic variant), and the other with focal seizures with alexia (focal variant with alexia). In the myoclonic variant, EEG discharges are brief and bilaterally synchronous. In the focal variant, ictal alexia is associated with a left posterior temporal ictal discharge. Ictal functional neuroimaging of the myoclonic variant shows multiple cortical hyperexcitable areas in the neuronal networks that subserve speech and language. In the focal variant, ictal functional neuroimaging shows mainly focal hyperexcitability in the dominant posterior temporo-occipital regions. The syndrome is nonprogressive. Seizures are generally well-controlled with pharmacotherapy, although some patients need to limit or avoid reading to achieve seizure-freedom, a potential cause of significant disability for those in whom reading is an essential part of their life and profession. Clonazepam and broad spectrum antiseizure medications can be effective in the myoclonic form of epilepsy with reading induced seizures. Carbamazepine and other antiseizure medications effective for focal seizures have been advocated for treatment for the focal form with alexia. In this article, we detail developments in our understanding of the clinical manifestations, pathophysiology, genetics, EEG, functional neuroimaging, and treatment of epilepsy with reading induced seizures.

Key points

Epilepsy with reading induced seizures is characterized by:

• Epileptic seizures that are primarily triggered by the act of reading.

• A variant with brief (for seconds) jaw myoclonus as the main seizure type.

• A second variant with exclusively focal seizures manifesting with alexia or dyslexia.

• Generalized tonic-clonic seizures are rare and mainly occur if reading continues despite the appearance of either jaw myoclonus or alexia.

• A prolonged latency from the stimulus onset (reading) to the clinical or EEG response (minutes to tens of minutes).

• Onset in late puberty through young adulthood, with a male predominance. Although the syndrome is not progressive, seizure susceptibility often persists into later life.

• Seizure control with antiseizure medications, with limitations on reading in some cases.

Historical note and terminology

Bickford and colleagues were the first to describe seizures induced by reading. They distinguished two types of reading epilepsy: ‘‘primary reading epilepsy’’ in which seizures occurred only in relation to reading and “secondary reading epilepsy” in which reading was not the sole stimulus (05). Since the original description it has been recognized that in many patients clinically identical seizures can also be provoked by linguistic activities other than reading, such as writing or speaking. The term “language-induced epilepsy” has been proposed as an alternative (16; 27). To conform to current terminology, this article uses the term “epilepsy with reading-induced seizures” (46).

Epilepsy with reading-induced seizures was initially classified by the ILAE together with the benign childhood focal epilepsies (09); this was debated by many authorities because reading epilepsy has no common links with benign childhood focal seizures and because it is a purely reflex epilepsy (44; 27; 45; 04). In some reports, the ILAE has categorized epilepsy with reading-induced seizures as a “combined generalized and focal epilepsy syndrome with polygenic etiology” (46).

The concept and nomenclature have evolved over time. “Primary reading epilepsy” was defined as follows in the 1989 ILAE classification:

Primary reading epilepsy: All or almost all seizures in this syndrome are precipitated by reading (especially aloud) and are independent of the content of the text. They are simple partial motor (involving masticatory muscles) or visual, and if the stimulus is not interrupted, generalized tonic-clonic seizures may occur. The syndrome may be inherited. Onset is typically in late puberty, and the course is benign with little tendency to spontaneous seizures. Physical examination and imaging studies are normal, but EEG shows spikes or spike-waves in the dominant parieto-temporal region. Generalized spike and wave may also occur (09).

However, this definition refers to reading epilepsy manifesting mainly with jaw myoclonus, although advances also document another variant with focal seizures provoked by reading that manifest with alexia lasting for minutes without jaw jerks (27; 04; 15; 30; 40; 26) (see Table 1). Therefore, the following definition of epilepsy with reading induced seizures may be more appropriate:

Epilepsy with reading-induced seizures is a distinct form of reflex epilepsy in which all, or almost all, seizures are precipitated by the reading. There are two variants: the most common manifests with jaw myoclonus (myoclonic variant), and the other with focal seizures of alexia (focal variant with alexia).

Seizures may evolve into generalized tonic-clonic seizures if reading persists. See video EEG in (17). In the myoclonic variant, EEG discharges are brief, bilaterally synchronous, and often with a left-sided emphasis or focal, whereas in the variant characterized by alexia they are prolonged and localized to the dominant temporal lobe. In the myoclonic variant, ictal functional neuroimaging shows multiple cortical hyperexcitable areas that are part of the neuronal network that subserves the function of speech. In the focal variant, ictal functional neuroimaging shows mainly focal hyperexcitability in the dominant posterior temporo-occipital regions. Epilepsy with reading-induced seizures is nonprogressive, although seizure susceptibility can be enduring.

Table 1. Epilepsy with reading induced seizures: Myoclonic Variant Versus Focal Variant With Alexia

Myoclonic reading epilepsy

Focal reading epilepsy with alexia

Sex

Males predominate

Males predominate

Age at onset

Mainly 15 to 18 years

Mainly 15 to 18 years

Family history

Yes

No

Main symptoms of seizures

Jaw myoclonus

Alexia

Duration of seizures

Brief in seconds

Longer in minutes

Progression to secondarily GTCS

Yes

Yes

Other types of seizures

Myoclonic jerks

Probably GTCS

Precipitating factors

Reading but also other linguistic activities (writing, talking)

Reading only

Ictal EEG

Mainly bilateral singular sharp waves predominating in the left temporo-parietal regions

Focal discharges of slow waves and spikes localized in the dominant posterior temporo-occipital regions

Pathophysiology

Probably a diffusely hyperexcitable network subserving reading

Focal hyperexcitability in the dominant temporo-occipital junction (mainly angular gyrus)

Prognosis

Relatively good but lifelong and causing disability of reading

Relatively good but lifelong and causing disability of reading

Treatment

Modification of reading and other precipitating factors

Modification of reading and other precipitating factors

Prophylactic treatment with antiseizure medications

Consider broad spectrum antiseizure medications and clonazepam

Consider drugs effective for focal epileptic seizures

The most recent ILAE update of the diagnostic criteria for the epilepsy syndromes includes the myoclonic variant only and considers focal seizures arising in occipito-temporal networks induced by reading as part of the differential diagnosis (46).

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