Narrow-band filtering for monitoring low-amplitude cone electroretinograms in retinitis pigmentosa.
Low amplitude (less than 10 microV) cone electroretinograms, elicited with 30-Hz white flicker from 59 patients with retinitis pigmentosa, were computer-averaged alone or in combination with a narrow-band electronic filter that increases the signal to noise ratio, thereby making it possible to evaluate the electroretinograms of most patients with retinitis pigmentosa. Narrow-band filtering reduced the amplitude of computer-averaged responses by an average of 7%, but the change in amplitude was independent of the size of the unbandpassed response. Narrow-band filtering also allowed measurement of 30-Hz cone responses in patients followed up over an 11- to 15-year period and quantitation of responses of less than 1 microV, which were not detectable with computer averaging alone.
Andréasson
S O
SO
Berman-Gund Laboratory, Massachusetts Eye and Ear Infirmary, Boston 02114.
Sandberg
M A
MA
Berson
E L
EL
D000293:Adolescent; D000328:Adult; D003936:Diagnosis, Computer-Assisted; D004596:Electroretinography / Q000295:instrumentation; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D012174:Retinitis Pigmentosa / Q000503:physiopathology*