LXXIX The Association of Nerve Deafness and Retinitis Pigmentosa Interval Report

Evaluation of pure tone and speech discrimination changes in Usher's syndrome

Twenty-three adult patients with type 2 Usher's syndrome were evaluated for changes in pure tone average (PTA), discrete frequency thresholds, and speech discrimination scores. These patients were evaluated over a period of 5 years on the average (range, 2 to 9 years). Analyses of ear data showed a less than 10-dB change on PTA and discrete frequency thresholds for most ears. Of the ears that showed a threshold change greater than or equal to 10 dB, statistical significance was reached only at 4,000 Hz (p less than .01), where 11 ears representing ten patients dropped 10 to 15 dB. Speech discrimination data showed a greater than or equal to 16% change in score for 18 ears (12 patients). Sixteen of those ears (ten patients) had a 16% to 52% decrease in score (p less than .01), and the remaining two ears (two patients) showed a 20% and 30% improvement in score. These findings document little or no change in pure tone sensitivity for type 2 Usher's syndrome patients, but demonstrate the importance of monitoring their speech discrimination performance.

Congenital mirror movements

In this report are described seven patients assessed clinically and neuropsychologically in whom mirror movements affecting predominantly the hands occurred as a congenital disorder. These mirror movements, representing a specific type of abnormal synkinesia, may arise as a hereditary condition, in the presence of a recognisable underlying neurological abnormality, and sporadically, and the seven patients provide more or less satisfactory examples of each of these three groups. Despite the apparent uniformity of the disorder, the heterogeneity and variability may be marked, examples in some of our patients including the pronounced increase in tone that developed with arm movement, and the capacity for modulation of the associated movement by alteration of neck position and bio-feedback. Various possible mechanisms are considered; these include impaired cerebral inhibition of unwanted movements, and functioning of abnormal motor pathways. Emphasis has been placed on the putative role of the direct, crossed corticomotoneurone pathways and on the unilateral and bilateral cerebral events that precede movement.

Heterogeneity of retinal degeneration and hearing impairment syndromes

Retinal abnormalities associated with hearing loss may be inherited alone or with additional manifestations. Environmental insults, such as rubella embryopathy, may also cause these abnormalities. We studied 13 patients with retinal abnormalities and hearing loss. Five had Usher's syndrome (retinitis pigmentosa and hearing impairment), one had crystalline retinopathy, two had associated enamel dysplasias, two had clumped pigmentary retinopathy, and three had Amalric-Diallinas syndrome. Our findings suggest considerable heterogeneity of syndromes involving retinal abnormalities and hearing loss.