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E.Y. Park, J. Nam, K. Holopigian, W. Seiple; Relationship Between Temporal Frequency Sensitivity and mfERG Kernel Responses in Patients With Retinitis Pigmentosa . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3429.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: It has been reported that there are two patterns of mfERG responses observed in patients with retinitis pigmentosa (RP): Pattern 1 – patients who have local areas with small amplitude first–order kernel amplitudes associated with normal or slightly delayed timing. These patients have measurable second–order kernel responses; and Pattern 2 – patients who have local areas with relatively large and delayed first–order responses. This group has very small and delayed, or absent second–order amplitudes. We examined whether the differences in these patterns of mfERG responses are related to differences in temporal frequency sensitivity. Methods: mfERG responses were recorded under standard conditions using 0F, 2F, and 4F sequences. First–order and first slice of the second–order response amplitude and timing were computed using a template–fitting program.Hood & Li, 1997 ERG flicker sensitivities were also measured over a range of frequencies from 17 to 75 Hz using a Ganzfeld flash stimulus. A group of ten patients with RP were tested and their responses were compared to the responses of a group of five control subjects. Results: We found that patients who had relatively normal mfERG first– and second–order wave shapes (Pattern 1) had reduced, but measurable ERG flicker responses at higher temporal frequencies. In contrast, those patients with mfERG response amplitudes that fell into Pattern 2 had ERG flicker deficits at higher temporal frequencies. In fact, none of the patients in this group had flicker following responses at 75 Hz. Conclusions: These results demonstrate that abnormal high temporal frequency sensitivity is related to abnormal temporal adaptation as measured using the mfERG.
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