International Ophthalmology

, Volume 38, Issue 6, pp 2435–2444 | Cite as

Time and frequency components of ERG responses in retinitis pigmentosa

  • Samira Ebdali
  • Bijan HashemiEmail author
  • Hassan Hashemi
  • Ebrahim Jafarzadehpur
  • Soheila Asgari
Original Paper



To evaluate the effects of retinitis pigmentosa (RP) on time, frequency, and time–frequency components of Xenon flash ERG signals using Fourier and wavelet transforms.


Xenon flash ERG was done in 18 eyes of nine RP patients and 20 normal eyes. After examining latency and amplitude, Fourier and wavelet transforms were performed using MATLAB software. Then, we extracted the mode frequency from the Fourier transform and main frequencies and their occurrence time from the wavelet transform. Finally, mean differences were analyzed using statistical tests.


The results indicated increased latency and reduced ERG wave amplitude, no significant inter-group difference in the average mode frequency, and significant reduction in main signal frequencies and their increased occurrence times. Also one or two of the three main frequencies had disappeared in more advanced cases.


Retinitis pigmentosa can induce changes in ERG time and time–frequency components. Impacted areas can be identified more accurately by wavelet transform and converting scales to frequencies.


Electroretinogram Retinitis pigmentosa Fourier transform Wavelet transform 



This report concerns a postgraduate research project for a master’s degree in medical physics at Tarbiat Modares University by the first author under the supervision of the second and third authors at Noor Ophthalmology Research Center. The authors wish to express their appreciation for the sincere assistance of ophthalmologists, optometrists, and the staff at the Electrophysiology Unit of Noor Eye Hospital, particularly Mrs. Shariati.

Compliance with ethical standards

Conflict of interest

All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.

Ethical approval

The study protocol adhered to the tenets of the Helsinki declaration and was approved by the Ethics Committee of Tarbiat Modares University.


  1. 1.
    Birch DG (2006) Retinitis pigmentosa. In: Heckenlively JR, Arden GB (eds) Principles and practice of clinical electrophysiology of vision. MIT Press, Cambridge, pp 781–794Google Scholar
  2. 2.
    Hamel C (2006) Retinitis pigmentosa. Orphanet J Rare Dis 1:40CrossRefGoogle Scholar
  3. 3.
    Camacho ET, Wirkus S (2013) Tracing the progression of retinitis pigmentosa via photoreceptor interactions. J Theor Biol 317:105–118CrossRefGoogle Scholar
  4. 4.
    Ropstad EO, Narfstrom K (2007) The obvious and the more hidden components of elecroretinogram. EJCAP 17:290–296Google Scholar
  5. 5.
    Berson EL (1993) Retinitis pigmentosa. The Friedenwald Lecture. Invest Ophthalmol Vis Sci 34:1659–1676PubMedGoogle Scholar
  6. 6.
    Karimi HH, Jafarzadehpur E, Blouri B, Hashemi H, Sadeghi AZ, Mirzajani A (2012) Frequency domain electroretinography in retinitis pigmentosa versus normal eyes. J Ophthalmic Vis Res 7:34–38Google Scholar
  7. 7.
    Cideciyan AV, Jacobson SG (1993) Negative electroretinograms in retinitis pigmentosa. Invest Ophthalmol Vis Sci 34:3253–3263PubMedGoogle Scholar
  8. 8.
    Seiple WH, Holopigian K, Greenstein VC, Hood DC (1993) Sites of cone system sensitivity loss in retinitis pigmentosa. Invest Ophthalmol Vis Sci 34:2638–2645PubMedGoogle Scholar
  9. 9.
    Alexander KR, Barnes CS, Fishman GA (2003) ON-pathway dysfunction and timing properties of the flicker ERG in carriers of X-linked retinitis pigmentosa. Invest Ophthalmol Vis Sci 44:4017–4025CrossRefGoogle Scholar
  10. 10.
    Falsini B, Iarossi G, Fadda A, Porrello G, Valentini P, Piccardi M, Scullica L (1999) The fundamental and second harmonic of the photopic flicker electroretinogram: temporal frequency-dependent abnormalities in retinitis pigmentosa. Clin Neurophysiol 110:1554–1562CrossRefGoogle Scholar
  11. 11.
    Nair SS, Joseph KP (2014) Wavelet based electroretinographic signal analysis for diagnosis. Biomed Signal Process Control 9:37–44CrossRefGoogle Scholar
  12. 12.
    Barraco R, Adorno DP, Brai M, Tranchina L (2014) A comparison among different techniques for human ERG signals processing and classification. Phys Med 30:86–95CrossRefGoogle Scholar
  13. 13.
    Gauvin M, Lina JM, Lachapelle P (2014) Advance in ERG analysis: from peak time and amplitude to frequency, power, and energy. Biomed Res Int 2014:246096. CrossRefPubMedPubMedCentralGoogle Scholar
  14. 14.
    Gauvin M, Chakor H, Koenekoop RK, Little JM, Lina JM, Lachapelle P (2016) Witnessing the first sign of retinitis pigmentosa onset in the allegedly normal eye of a case of unilateral RP: a 30-year follow-up. Doc Ophthalmol 132:213–229CrossRefGoogle Scholar
  15. 15.
    Hashemi H, Fotouhi A, Mohammad K (2003) The Tehran Eye Study: research design and eye examination protocol. BMC Ophthalmol 3:8CrossRefGoogle Scholar
  16. 16.
    McCulloch DL, Marmor MF, Brigell MG, Hamilton R, Holder GE, Tzekov R, Bach M (2015) ISCEV standard for full-field clinical electroretinography (2015 update). Doc Ophthalmol 130:1–12CrossRefGoogle Scholar
  17. 17.
    Barraco R, Adorno DP, Brai M (2011) ERG signal analysis using wavelet transform. Theory Biosci 130:155–163CrossRefGoogle Scholar
  18. 18.
    Drissi H, Regragui F, Antoine J-P, Bennouna M (2000) Wavelet transform analysis of visual evoked potentials: some preliminary results. ITBM-RBM 21:84–91CrossRefGoogle Scholar
  19. 19.
    Janaky M, Palffy A, Horvath G, Gb Tuboly, Benedek G (2008) Pattern-reversal electroretinograms and visual evoked potentials in retinitis pigmentosa. Doc Ophthalmol 117:27–36CrossRefGoogle Scholar
  20. 20.
    Parisi V, Ziccardi L, Stifano G, Montrone L, Gallinaro G, Falsini B (2010) Impact of regional retinal responses on cortical visually evoked responses: multifocal ERGs and VEPs in the retinitis pigmentosa model. Clin Neurophysiol 121:380–385CrossRefGoogle Scholar
  21. 21.
    Cuenca N, Fernandez-Sanchez L, Campello L, Maneu V, De la Villa P, Lax P, Pinilla I (2014) Cellular responses following retinal injuries and therapeutic approaches for neurodegenerative diseases. Prog Retin Eye Res 43:17–75CrossRefGoogle Scholar
  22. 22.
    Hood DC, Birch DG (1996) Abnormalities of the retinal cone system in retinitis pigmentosa. Vis Res 36:1699–1709CrossRefGoogle Scholar
  23. 23.
    Berson EL (1992) Electrical phenomena in the retina. In: Hart WM (ed) Adler’s physiology of the eye, 9th edn. Mosby, US, pp 641–708Google Scholar
  24. 24.
    Scholl HP, Kremers J (2000) Large phase differences between L-cone– and M-cone–driven electroretinograms in retinitis pigmentosa. Invest Ophthalmol Vis Sci 41:3225–3233PubMedGoogle Scholar
  25. 25.
    Fariss RN, Li ZY, Milam AH (2000) Abnormalities in rod photoreceptors, amacrine cells, and horizontal cells in human retinas with retinitis pigmentosa. Am J Ophthalmol 129:215–223CrossRefGoogle Scholar
  26. 26.
    Wen Y, Klein M, Hood DC, Birch DG (2012) Relationships among multifocal electroretinogram amplitude, visual field sensitivity, and SD-OCT receptor layer thicknesses in patients with retinitis pigmentosa. Invest Ophthalmol Vis Sci 53:833–840CrossRefGoogle Scholar
  27. 27.
    Birch DG, Sandberg MA (1987) Dependence of cone b-wave implicit time on rod amplitude in retinitis peigmentosa. Vis Res 27:1105–1112CrossRefGoogle Scholar
  28. 28.
    Hamasaki DI, Liu M, Qiu H, Fujiwara E, Lam BL (2002) The a-wave latency in control subjects and patients with retinal diseases. Jpn J Ophthalmol 46:433–442CrossRefGoogle Scholar
  29. 29.
    Wen Y, Locke KG, Hood DC, Birch DG (2011) Rod photoreceptor temporal properties in retinitis pigmentosa. Exp Eye Res 92:202–208CrossRefGoogle Scholar
  30. 30.
    Janaky M, Palffy A, Deak A, Szilagyi M, Benedek G (2007) Multifocal ERG reveals several patterns of cone degeneration in retinitis pigmentosa with concentric narrowing of the visual field. Invest Ophthalmol Vis Sci 48:383–389CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2017

Authors and Affiliations

  • Samira Ebdali
    • 1
  • Bijan Hashemi
    • 1
    Email author
  • Hassan Hashemi
    • 2
  • Ebrahim Jafarzadehpur
    • 3
  • Soheila Asgari
    • 4
  1. 1.Medical Physics Department, Faculty of Medical SciencesTarbiat Modares UniversityTehranIran
  2. 2.Noor Ophthalmology Research CenterNoor Eye HospitalTehranIran
  3. 3.Noor Research Center for Ophthalmic EpidemiologyNoor Eye HospitalTehranIran
  4. 4.Department of Epidemiology and Biostatistics, School of Public HealthTehran University of Medical SciencesTehranIran

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