Reflex epilepsies Presented by Prof. AbdulrahmanSallam Professor of Neurology Sana’a university
Introduction • Epileptic seizures can arise in a ‘spontaneous’ fashion with no detectable precipitating factors, or they can be provoked by certain recognizable stimuli. • Stimuli that contribute towards the initiation of a seizure are provided by the individual’s internal and external environment.
Introduction • Internal factors as hormones, electrolytes, state of consciousness and body temperature. • External factors may be sensory, electrical or biochemical.
Introduction • Reflex seizures have a 4–7% prevalence among patients with epilepsies. • Their aetiology may be idiopathic or symptomatic.
Classification of reflex epilepsies • With reference to the classifications of the epileptic syndromes of the International League Against Epilepsy (ILAE) (1989), reflex epilepsies can be recognized with among generalized and focal epileptic syndromes, and with among idiopathic and symptomatic.
Classification of reflex epilepsies • Reflex seizures can be either generalized or focal, with or without impairment of consciousness. • It may be genetically inherited or acquired supported by a brain lesion.
Classification of reflex epilepsiesList of reflex epileptic seizures • 1- Induced by simple stimuli Visual induced epilepsy - Photosensitive epilepsy - Television-induced epilepsy - Pattern-induced epilepsy - Video-games induced epilepsy - On closing the eyes epilepsy - Visual exploratory epilepsy
Classification of reflex epilepsiesList of reflex epileptic seizures 1- Induced by simple stimuli Somatosensory-evoked epilepsy - Movement-induced epilepsy - Startle-induced epilepsy - Tooth-brushing epilepsy -Amputees’ epilepsy - Auricular epilepsy - Rubbing epilepsy
Classification of reflex epilepsiesList of reflex epileptic seizures 2. Induced by complex stimuli - Eating epilepsy - Hot-water epilepsy - Water-immersion epilepsy
Classification of reflex epilepsiesList of reflex epileptic seizures 3. Induced by higher cerebral functions - Language induced epilepsy - Reading epilepsy - Writing (graphogenic) epilepsy - Speaking-induced epilepsy - Musicogenic epilepsy - Voice-induced epilepsy - Playing-music epilepsy Telephone-induced epilepsy- -EpilepsiaArithmetices - Games-induced epilepsy - Decision-making epilepsy - Thinking epilepsy - Praxis-induced epilepsy
Classification of reflex epilepsiesList of reflex epileptic seizures 4. With self-induced seizures -Photosensitive epilepsy with self-induced seizures. - Sunflower epilepsy.
Reflex epilepsy related to visual stimuli • Photosensitivity is the susceptibility to produce epileptic seizures in response to light stimuli. • It has higher prevalence in females and in the adolescence.
Reflex epilepsy related to visual stimuli • Photosensitivity can be found in a wide range of epilepsies. • It is very frequent in idiopathic generalized epilepsies, in particular in juvenile myoclonic epilepsy.
Reflex epilepsy related to visual stimuli • Photosensitivity is also found in some idiopathic focal epileptic syndromes, in particular, (idiopathic photosensitive occipital lobe epilepsy). • In some symptomatic generalized epilepsies, in particular, (progressive myoclonic epilepsies).
Reflex epilepsy related to visual stimuli • The most frequently found EEG pattern is the photoparoxysmal response, usually easily provoked in laboratory with intermittent light stimulation .
Reflex epilepsy related to visual stimuli • Seizures can be triggered by natural flickering light such as rays of sunlight filtering through the trees, or reflected by the waves of the sea or snow.
Reflex epilepsy related to visual stimuli • The development of artificial light stimulation (television, video-games, and so on) has much increased the occurrence of seizures. • These seizures are usually clinically and EEG generalized in type (absence, myoclonus, tonic—clonic seizures).
Reflex epilepsy by calculation or other higher-level cortical processes
Reflex epilepsy by calculation or other higher-level cortical processes • EpilepsiaArithmeticesis idiopathic in nature and generalized in type. • Triggered by mental calculation or by other complex mental processes (thinking epilepsy), with the pressure to decide (decision-making epilepsy).
Primary reading epilepsy • Reading epilepsy is a rare form of reflex epilepsy in which almost all seizures are precipitated by reading. • Generalized seizures were always preceded by a clicking sensation or actual jerks in the jaws (i.e., jaw or tongue clicking) with generalized or focal (temporo-parieto-occipital areas) paroxysmal activity.
Startle epilepsy • Startle epilepsy isseizurestriggered by a sudden and unexpected auditory stimulus. • Patients have usually large brain lesions, mostly perinatal hypoxic injury (Little syndrome, congenital hemiparesis), and frequently they show also enhanced startle reaction.
Startle epilepsy • Startle seizures have been reported also in large or focal dysplasias, in Lennox Gastaut syndrome and in Down syndrome.
Eating epilepsy • Eating-induced seizures arerare seizures, exclusively triggered by eating (eating epilepsy). • Seizures are generally partial, more often complex partial, generalized seizures may coexist, in particular atypical absences.
Eating epilepsy • Amygdala play an important role as an integrative centre, particularly in temporo-mesial focal seizures. • Bulky meals rich in carbohydrates have been postulated as possible triggering factors.
Musicogenic epilepsy • Musicogenic epilepsy is a form of temporal lobe epiIepsy and belongs to the group of reflex epilepsies. • Musicogenic epilepsy isaseizure induction by listening to the music.
Musicogenic epilepsy • The musicogenic epilepsy has a strong correlation to the temporal lobe mainly mesial side. • The majority of cases appear to depend on a certain emotional reaction mediated through limbic mesial temporal lobe structures.
Musicogenic epilepsy • Seizures are typically complex partial, with possible secondary generalization, and more rarely simple partial. • Autonomic symptoms and signs may occur before onset of the ictal behavior.
Hot-water epilepsy • Hot-water epilepsy is triggered by contact or immersion in hot water. • This type of epilepsy is frequent in southern of India. • This form of geographically specific reflex epilepsy is age related, more frequent in males, usually self-limited and frequently familial.
Other unusual seizure triggers • Seizures may be elicited by particular stimulations such as skin friction (rubbing epilepsy), touching or tapping, tooth brushing (tooth-brushing epilepsy), stimulation of external ear conduct (auricular epilepsy).
Other unusual seizure triggers • Usually these reflex seizures are linked to brain lesions of various type (dysplastic, inflammatory as in Rasmussen syndrome). • Involving the parietal and sensorimotor cortex or supplementary motor area, but other regions may be involved, namely temporal lobe.
Importance of reflex seizures and reflexepilepsies • Reflex epilepsies represent an interesting topic that has always aroused curiosity in epileptologists. • The recognition of provocative stimuli may contribute to the management of epilepsy.
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