A relationship between autoimmune thyroiditis and benign paroxysmal positional vertigo?

Benign paroxysmal positional vertigo (BPPV) is a labyrinthine disorder with a typical behavior: intense crises of rotational vertigo induced by postural changes of the head, with short duration and usually good responsiveness to rehabilitative maneuvers. This phenomenon is thought to be subsequent to the movement of floating particles in the labyrinthine fluids, which can provoke gravitational stimulations. In order to conduct a metabolic and autoimmune examination, 70 patients affected by BPPV were examined. In 34 cases (48.5%) autoimmune alterations were found: in 19 cases (27.1%) the level of anti-thyroid antibodies far exceeded the normal values with a significant incidence in comparison with a control group (P<0.01). No other 'risk factors' were present. It can be hypothesized that the diffusion of immune-complexes in the inner ear could change the composition of the endolymphatic fluid exerting a mechanical stimulation of the receptors and provoking the typical vertigo.

Some experiments on temporary threshold shifts produced by short tones.

TTSs produced by short (500-1000 msec) pure frequency (2000, 3000, 4000 c.p.s.) tones on normal young subjects show, under comparable conditions, the same essential characteristics as TTSs which follow longer stimulations. In particular, they show a tendency to a displacement of their maximal values, as soon as the stimulating tone is presented at adequately high (100 dB SPL) intensity levels, towards a frequency about a halfoctave higher than that of the stimulating tone. In our experiments, however, this tendency was more clearly and constantly demonstrable following stimulations with 3000 c.p.s. tones. Significant individual variations in quantitative aspects of the TTSs have been observed. It is suggested that the use of short tones may be easier and more applicable in practice in investigations concerning the after effects of acoustical stimulation and possible also in procedures aimed at obtaining a better understanding of the significance of individual variations in the behaviour of the receptor organ upon exposure to high intensity stimulations.

Small acoustic neuromas: monitoring the growth rate by MRI.

In a proportion of small acoustic neuroma patients, monitoring with magnetic resonance imaging shows no volumetric increase of tumour size over the years. The object of the study was to identify some indications for the clinical choice between immediate surgery (with the related risks) and watchful waiting. We performed a retrospective study of 47 non-surgically-treated patients affected by acoustic neuroma and monitored by gadolinium-enhanced MRI between January 1990 and February 1999. Six clinical variables (tumour size, sex, age, initial symptoms, ABR pattern and duration of the symptoms) were examined by univariate analysis. Chi-square test and variance analysis were performed to evaluate the statistical significance. In 30/47 (63.8%) cases, no growth was observed during the entire period of follow-up. In the remaining 17/47 (36.2%) patients, a volumetric increase was detected, most often within the first year of observation. The clinical factors examined did not significantly correlate with growth. Despite the relatively short period of observation, we believe that immediate surgery does not need to be considered mandatory for small acoustic neuromas, even in young patients. However the irregular behaviour of the tumour underlines the importance of monitoring with MRI at least once a year.