After reviewing the "flash" literature, we speculate on ways that millisecond photic stimulation
could be applied in the clinic.
Other EEG studies (see Sadleir, Scheffer & Smith, 2008; Sadleir, Scheffer, Smith, Carstensen, Farrell & Connolly, 2009) have also been used in the diagnosis of other CAE features such as photic stimulation
, and hyperventilation.
To detect brain responses, we measured event-related potentials (ERP) while a photic stimulation
was applied repetitively.
Electroencephalography: Background activity, response to intermittent photic stimulation
, hyperventilation, and other pathological findings were investigated by an experienced clinical neurophysiologist (BB).
and hyperventilation were used during the EEG recordings.
These responses include single-tentacle responses, coordinated tentacular responses, and responses to direct on-off photic stimulation
of the rhopalia.
Photoparoxysmal response (PPR) is defined as the occurrence of spikes, spike waves, poly-spike waves, or repetitive spikes in response to intermittent photic stimulation
, which was observed in 30 patients (34.5%), while focal EEG abnormalities were recorded in 25 of our patients (28.7%).
Intermittent photic stimulation
was carried out in all patients with eyes closed.
More common techniques used to provoke all patients with seizures include hyperventilation, photic stimulation
, sleep deprivation, and AED withdrawal.
d) Photic stimulation
at frequencies 1, 3, 5, 6, 7, 10, 15, 20, 25 and 30/Sec.
Most (117) underwent intermittent photic stimulation
EEG between seizures.
For the EEG studies we used a the Neuroscop-416 16-channel electroencephalograph with electrodes, manufactured by BIOLA Ltd, Moscow, a cap for affixing the electrodes, goggles to provide rhythmic photic stimulation
and a computer (P4 processor with a 512 MB memory, and a 200 GB disk) loaded with the Neuroscop program for recording, storing and analyzing resulting data.