At the Otorhinolaryngology Department of the Vila Nova de Gaia Hospital Centre, we use a protocol for assessing patients with balance disorders, which includes Brainstem Auditory Evoked Potentials, cranio-corpus-graphy (C.C.G.) and electronystagmography (E.N.G.). Using E.N.G., we record spontaneous nystagmus, fixation nystagmus, the caloric test (alternating binaural caloric test) and the rotational test (damped-intensity rotational test). These two tests are recognised as representing stimuli of different intensities, with the rotational test being the strongest stimulus for the vestibular system. We thus have data that allow us to compare the vestibular system’s responses to stimuli of different intensities. According to Claussen, this Comparison of Responses to Stimuli of Different Intensities (C.R.E.I.D.) is extremely informative, and three general patterns can essentially be defined: 1. Parallel behaviour (responses to caloric and rotational stimuli of the same type, both normal, inhibited or irritative); 2. Recruitment (inhibited caloric test and normal or disinhibited ipsilateral rotatory test, or normal or inhibited caloric test and disinhibited rotatory test); and 3. Decuting (the inverse phenomenon, a stronger response to the weaker stimulus). These patterns are further subdivided by Claussen, who defines nine different types of C.R.E.I.D. The aim of this study is to determine whether, in our series of patients with peripheral vestibular disease, we could identify any particular type or types of C.R.E.I.D. and whether these types would have any implications in terms of prognosis.

We concluded that, in our sample of 69 patients with peripheral vestibular disease, the most common C.R.E.I.D. types are types III and IV, and that this finding appears to us to be highly significant. We also believe that type IV responds very well to vestibular rehabilitation therapy and, in our opinion, is associated with a better prognosis.