Photoparoxysmal response

• Epileptiform discharges provoked by intermittent photic stimulation (flickering light)
• Classfied in four types of photoparoxysmal response according to Waltz:
  • Waltz 1: Spikes within the occipital rhythm
  • Waltz 2: Parieto-occipital spikes with a biphasic slow wave
  • Waltz 3: Parieto-occipital spikes with a biphasic slow wave and spread to the frontal region
  • Waltz 4: Generalized spikes and wave or polyspikes and wave

Clinical relevance

• Photoparoxysmal responses are frequently found in nonepileptic children.
• The prevalence of photosensitivity in nonepileptic individuals ranges from 0.5 to 8.9% of the population and rarely evolve into epilepsy
• Only generalized paroxysmal epileptiform discharges (Waltz 4) are clearly linked to epilepsy.
• The majority of individuals with photosensitive seizures does not need anticonvulsant therapy
• Most effective treatment is avoidance of provoking stimulus.
• Photosensitive epilepsy is also linked to headache.

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Waltz 2 photoparoxysmal respons in a 11 year old girl, bilateral spike slow wave in parieto-occipital reagions (source)

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Notes