Search

Highlights: [•] Sustained PERG response recording was applied to the evaluation of MS patients in a clinical setting. [•] Results show a severe reduction of habituation effect, while other PERG parameters remain normal. [•] Discussion consider the possible role of alterations in the metabolism of glial cells. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Sustained pattern stimulation (SPS) induces habituation in the normal pattern electroretinogram (PERG). In this study, the authors evaluated whether sustained flicker stimulation (SFS) induces habituation in the normal flicker ERG (FERG). Methods: FERGs were elicited in normal volunteers by an 8Hz flicker stimulus, presented continuously over 3min after 20min of light adaptation. One stimulus temporal period was sampled and averaged in packets (n =20) of 60 events, each of 8s duration. Amplitudes and phases of the response 1st and 2nd harmonics (1F and 2F, respectively) were measured. FERG results were compared with those obtained by recording PERGs with a similar SPS paradigm. Results: During SFS, FERG 2F showed a modest increase in amplitude (about 25%, p <0.05). No changes were observed for the 1F amplitude and for the phase of both components. In contrast, PERG amplitude showed SPS-induced habituation, described by an exponential decay with a time constant of ∼20s. Conclusions: The normal FERG, unlike PERG, does not show habituation, suggesting that the adaptive changes of retinal neurons underlying FERG are different from those of PERG generators. Significance: Our findings may have implications for diagnosis and/or pathophysiology of retinal disorders involving the inner retina. [Copyright &y& Elsevier]