Comparative Analysis of Visual Function,
Hkarinc Asility and Olfactory Sense in Usher's Syndrome.


Background: Usher's syndrome is a genotypically and phenotypically heterogeneous group of diseases with autosomal recessive heredity. Clinically, patients present with retinitis pigmentosa (RP) and hearing loss, which is moderate in type II and profound in type I patients. The latter also express vestibular abnormalities. The following work represents first results &om a joint effort of the University Eye and ENT Hospitals at Tuebingen in cooperation with the german RP patient organisation (DRPV) to improve phenotyping. Following preliminary reports of olfactory deficits, a new threshold test was used to quantitatively assess the olfactory sense. Methods: 39 patients with Usher I (8) or II (31) were seen in both the outpatient clinic for hereditary retinal disorders and the ENT clinic on the same day. The protocol included history, basic eye exam, Goldmann perimetry, electroretinography (ISCEV standard), and morphology of anterior and posterior segments. Findings were entered into a relational data base. Additionally, the results of an ENT examination, audiometry, and the Erlanger Riechtest ("sniffing sticks") were recorded. Results: Practically all Usher patients had a progressed form of RP. Mean visual acuity was 0.52 (type I) and 0.62 (type II), respectively, and the visual field was ver constricted (median of remaining field 0.0175 and 0.05 steradiant, respectively). The ERG was non-detectable or could only be obtained using maximal stimulation (response median of the scotopic 10Hz tlicker 0 and 0.87 pV, and of the photopic 30Hz flicker 0.29 and 0.7 pV, respectively). The mean hearing loss (speech audiogram) was 97 and 42%, respectively. The median of the olfactory threshold was, however, unremarkable (9.7 and 8.5 vs. 8.5 in normals). Discussion: Both groups showed a progressed RP, however, the differences between type I and II were not as impressive as in the audiograms. An affection of the olfactory system could not be found, and there was also no correlation between parameters resembling visual function, hearing ability, and olfactory sense. This could be important for the diagnostic differentiation from Refsums syndrome.

Mathias Seeliger 1, Krisna Gendo 1, Eberhart Zrenner 1, Markus Pfister 2, Steffen Paasch 2 und Hans-Peter Zenner 2

1 University Eye Hospital, Dept. II, Schleichstr. 12-16, D-72076 TObingen
2 University Ear, Nose, and Throat Hospital, Silcherstr. 5, D-72076 TUbingen Supported by DFG grants Ru 457/1-2 and Zr 1/7-3)

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