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Influence of Dopamine Deficiency in Early Parkinson's Disease on the Slow Stimulation Multifocal-ERG

Palmowski-Wolfe, Anja ; Perez, Maria ; Behnke, Stefanie ; Fuss, Gerhard ; Martziniak, Martin ; Ruprecht, Klaus

In: Documenta Ophthalmologica, 2006, vol. 112, no. 3, p. 209-215

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    Titre
    • Influence of Dopamine Deficiency in Early Parkinson's Disease on the Slow Stimulation Multifocal-ERG
    Auteur
    • Palmowski-Wolfe, Anja. Department of Ophthalmology, University of Saarland, D 66421, Homburg, Germany
    • Perez, Maria. Department of Ophthalmology, University of Saarland, D 66421, Homburg, Germany
    • Behnke, Stefanie. Department of Neurology, University of Saarland, D 66421, Homburg, Germany
    • Fuss, Gerhard. Department of Neurology, University of Saarland, D 66421, Homburg, Germany
    • Martziniak, Martin. Department of Neurology, University of Saarland, D 66421, Homburg, Germany
    • Ruprecht, Klaus. Department of Ophthalmology, University of Saarland, D 66421, Homburg, Germany
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Documenta Ophthalmologica, 2006, vol. 112, no. 3, p. 209-215. Springer-Verlag
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:311523
    Summary
    Purpose: In animal studies intravitreal injection of tetrodotoxin (TTX) results in mfERG waveform changes similar to those observed in glaucoma. As TTX blocks amacrine as well as ganglion cells, there is still a question regarding the underlying cell population responsible for these changes in waveform. In an attempt to assess the contribution of the amacrine cells to these changes, a mfERG was obtained from patients with Parkinson's disease as some amacrine cells are mediated by dopamine, a substance lacking in Parkinson's. Methods: Eight patients with early Parkinson's disease underwent ophthalmologic examination, testing of contrast sensitivity and electrophysiological examination according to ISCEV standard at least 12h following their last medication with Dopamine. A slow stimulation mfERG was obtained with a stimulus base interval of 53.3ms and with a stimulus base interval of 106.6ms. During MF-ERG recordings 103 hexagons stimulated the central 50deg of the retina simultaneously and independently (m-sequence 213, Lmax: 200cd/m2, ~100% contrast). Results: Contrast sensitivity and ISCEV standard electrophysiological testing was unremarkable. When the mfERG was analyzed, only four patients had an adequate signal-to-noise ratio to allow further data analysis - one of whom was diagnosed with a multi system atrophy in retrospect. The first order response component was analyzed at a filter setting of 10-300Hz and at 100-300Hz (OPs) and compared to mfERGs of a control group. On average, in patients, the amplitude of N1P1 was slightly lower in the central and nasal response averages. When the three OPs at a latency of 72-89ms were analyzed in the 53.3ms base interval recording, the most marked difference in amplitude was observed in the superior nasal response average of the first OP. Here a mean amplitude of 1.3nV/deg2 in patients compared to a mean amplitude of 1.9nV/deg2 in the control group (P: 0.08). Discussion: In contrast to our previous findings in NTG, there was a consistent presence of three OPs. Under the stimulus conditions applied, we did not find an influence of dopaminergic amacrine cells on the mfERG in our patients with moderate stages of Parkinsion's. The difficulties in obtaining an adequate signal-to noise ratio due to e.g. muscle artifacts even in Parkinson patients of moderate disease stages render a success of mfERG recording in patients with more advanced stages unlikely. The question of the influence of dopaminergic amacrine cells on the mfERG could possibly be addressed using MPDT in animal research