The age-related changes in the fast rate (70–110 Hz) auditory steady state response elicited by multiple-frequency tones (MSSR) that were amplitude-modulated (AM) are reported here. The MSSR was recorded in a sample of 64 well babies distributed into three age groups: 0–29 days (n = 25); 1–6 months (n = 26); 7–12 months (n = 13). Four simultaneously presented AM tones (0.5, 1, 2 and 4 kHz) were delivered monaurally through TDH 49 earphones, at different intensities (between 90 and 30 dB SPL). Clear developmental changes were found between birth and 12 months of age in response threshold, amplitude and detectability. Statistical analysis revealed that these changes occurred at different rates for low- and high- frequency responses. Nonetheless adult-like hearing thresholds were estimated reasonably well in most newborns and well babies, for all frequencies tested. Therefore the MSSR technique could be useful for objective frequency-specific audiometry beginning at birth.

The present study is concerned with a clinical analysis of 17 patients with "rebound nystagmus" examined over a period of three years. All of them have shown a short duration second degree nystagmus evoked by changes in the direction of fixation, from the lateral to straight ahead gaze. This nystagmus was a fixation nystagmus, that is to say, it was enhanced in the presence of active optic fixation and inhibited in its absence. Almost all the patients (16 out of 17) had cerebellar signs on neurological examination (in one subject rebound nystagmus was the first sign suggesting cerebellar involvement and appeared several months before any other cerebellar sign was present). Rebound nystagmus was far more common than the other neuro-otological signs suggesting cerebellar dysfunction (vestibular hyperexcitability, dysrhythmia in postcaloric nystagmus and ocular dysmetria). In three out of four patients with unilateral lesions rebound nystagmus was ipsilateral with respect to the side of the lesion. Postmortem studies were carried out upon five cases and showed either pathological changes in the cerebellum or a lesion involving the cerebellar peduncles in the brain stem.