Author/Authors :
Hassan-Karimi, Homa Department of Medical Physics - School of Medicine - Tehran University of Medical Sciences , Jafarzadehpur, Ebrahim Department of Optometry - Faculty of Rehabilitation - Tehran University of Medical Science , Blouri, Bahram Department of Medical Physics - School of Medicine - Tehran University of Medical Sciences , Hashemi, Hassan Farabi Eye Hospital - Tehran University of Medical Sciences , Zare Sadeghi, Arash Department of Medical Physics - School of Medicine - Tehran University of Medical Sciences , Mirzajani, Ali Department of Optometry - Faculty of Rehabilitation - Tehran University of Medical Science
Abstract :
Purpose: To compare electroretinogram (ERG) characteristics in patients with retinitis
pigmentosa (RP) and normal subjects using frequency domain analysis.
Methods: Five basic ERG recordings were performed in normal subjects and patients
with a clinical diagnosis of RP according to the ISCEV (International Society of Clinical
Electrophysiology of Vision) protocol. Frequency domain analysis was performed by
MATLAB software. Different frequency domain parameters were compared between
the study groups.
Results: Peak frequency (Fmod) of flicker and oscillatory responses in RP patients
showed significant (P<0.0001) high pass response as compared to normal controls.
Peak frequency (Fmod) of the other responses was not significantly different between
the two groups.
Conclusion: In addition to conventional ERG using time domain methods, frequency
domain analysis may be useful for diagnosis of RP. Oscillatory and flicker responses
may be analyzed in frequency domain. Fast Fourier transform may reveal two distinct
high pass responses (shift to higher frequencies) in Fmod. Time and frequency domain
analyses may be performed simultaneously with many modern ERG machines and
may therefore be recommended in RP patients.
Keywords :
Electroretinogram (ERG) , Retinitis Pigmentosa (RP) , Fast Fourier Transform (FFT) , Mod
