Suppressive Efficacies by Adaptive Temporal Filtering System on Photoparoxysmal Response Elicited by Flickering Pattern Stimulation

Abstract

Summary:Purpose: Based on our previous study that validated efficacies of an adaptive temporal filtering system (ATFS) suppressing a photoparoxysmal response (PPR) elicited by a chromatic flicker stimulation, we further studied ATFS efficacies on PPRs elicited by pattern-flicker stimulation in 13 photosensitive epilepsy patients.Methods: Subjects were 13 photosensitive epilepsy patients (two male and 11 female patients; mean age ± SD, 20.9 ± 8.9 years) who were all sensitive to a flickering geometric-pattern scene. We used a scene consisting of 15-Hz flickering 4 c/deg stripe images lasting for 4 s. With a 14-inch television set 2 m before a subject, we displayed the following video scenes: nonfiltered and filtered flickering-stripe scenes; for the latter, two kinds of ATFSs with mild efficacy and strong efficacy were used. Three flickering-stripe scenes altogether, each of which lasted for 4 s, were given at random with a 10-s interval.

Photosensitive epilepsy and image safety

“…A further development of this device allowed filtering of geometrical patterned flicker (alternating pattern). This was shown to be effective in thirteen patients (Takahashi et al, 2002).…”

Human photosensitivity: from pathophysiology to treatment

“…Recently, it was found that an adaptive temporal filter may be useful as a preventive measure of photosensitive seizures triggered by stimulative images from televisions or other displays (Takahashi et al. , 2001b, 2002; Harding and Takahashi, 2004).…”

Removal of epileptogenic sequences from video material

“…In contrast to previous attempts of implementing protective devices, 9,7 our method is able to preserve better the spatial properties and content of the video sequence while being able to decrease any potentially epileptogenic sequence based on colored images. Our approach differs substantially from the adaptive filtering, 8 which adjusts a temporal scaling setting according to the estimated risk of the video sequence.…”

“…2,5 Preventive measures have been proposed such as the use of optic filters 7 or low-pass filters. 8,9 These methods have been proven effective in decreasing the risk of triggering photoparoxysmal responses (PPRs) elicited by the Pokémon cartoon. However, these techniques have the drawback of changing noticeably the quality of the image.…”