Photosensitive epilepsies are characterized by visually-induced seizures. Flashing-light stimuli are known to induce seizures in some (but not all) patients. My question is whether people with this type of epilepsy can self-induce seizures by rapid eye blinking?
“Self-induction” in photosensitive epilepsy is a well-described and fascinating phenomenon. Photosensitivity itself is rare, occurring in only ~5% of patients with epilepsy.1 Among this group it has been estimated2 that 25% self-induce epileptiform activity. The most common methods appear to be passing a hand with open fingers repeatedly across the visual field and, as you query, blinking.
Quoting from a classical paper on the topic by Andermann et al:3
The method of inducing seizures varies both in detail and in principle. Light contrasts are always brought about, but they may either be applied to and alternate for the whole visual field—an effect produced by blinking or batting the eyelids and induced by any flickering light—or else the attack is elicited by the spatial displacement of brightness and darkness over the retina.
This phenomenon is most common in epileptics with established photic triggers, and the scenario triggering an attack is often in the context of bright sunlight. However, this has also been described in epileptics who are not otherwise photosensitive. See, for example, “Seizures triggered by blinking in a non-photosensitive epileptic.”4 Notably, some authors have questioned whether blinking and other “triggers” are actually themselves ictal phenomena (i.e. representing the initial phase of an epileptic event) rather than a form of voluntary self-induction. For more on that hypothesis, see Ames, 1971.5
Presuming that this is, in fact, self-induction as has been traditionally postulated, the question of why such patients repeatedly self-induce seizures is perhaps the most interesting aspect of this. There has been some research2 considering the psychiatric factors underlying the behavior. Quoting Andermann3 again:
The reward a patient seeks by self-stimulation may lie in escape from unwanted situations, in attracting attention, in punishing those around him, or, indeed, in deriving pleasure from the attack.
Kasteleijn-Nolst Trenité DG. Photosensitivity in epilepsy. Electrophysiological and clinical correlates. Acta Neurol Scand Suppl. 1989;125:3-149.
Ng BY. Psychiatric aspects of self-induced epileptic seizures. Aust N Z J Psychiatry. 2002 Aug;36(4):534-43.
Andermann K, et al. Self-induced epilepsy. A collection of self-induced epilepsy cases compared with some other photoconvulsive cases. Arch Neurol. 1962 Jan;6:49-65.
Rafal RD, Laxer KD, Janowsky JS. Seizures triggered by blinking in a non-photosensitive epileptic. J Neurol Neurosurg Psychiatry. 1986 Apr;49(4):445-7.
Ames FR. "Self-induction" in photosensitive epilepsy. Brain. 1971;94(4):781-98.