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The cochlear nuclei in two patients with Usher syndrome type I
M Wagenaar1, P Draaijer, H Meek
1Department of Otorhinolaryngology, University Hospital Nijmegen and Faculty of Medical Sciences, University of Nijmegen, The Netherlands.
Hypothesis:
Does long-term sound deprivation lead to degeneration of the cochlear nuclei in two Usher type I patients?
Methods:
The cochlear nuclei of these patients were morphometrically analyzed and compared with two age-matched controls. Routine autopsy of the brainstems was performed before the design of this study was known. During this procedure, the ventral cochlear nucleus (VCN) can easily be damaged. Five partially damaged VCN could nevertheless be analyzed for this study, including the right VCN of Usher patient 1 and both VCN of Usher patient 2. Using 15 microm thick serial paraffine sections of the cochlear nuclei, estimates of volume, neuronal densities, number of cells and mean cell diameter of the dorsal cochlear nucleus (DCN) and VCN were obtained.
Results:
This study presents unique material of the cochlear nuclei in two patients with Usher syndrome type I. Data regarding volume and total cell number of the VCN are influenced by the absence of a part of the VCN. Results suggest a decrease in mean cell diameter of the VCN in Usher patients. Other parameters of the VCN and DCN, however, showed no major differences between Usher type I patients and controls.
Conclusion:
Only minor degenerative changes are apparent in the cochlear nuclei of two patients with Usher type I, who were deprived of acoustic stimuli since birth.