Standardized Assessment
Dizziness, unsteadiness, nystagmus, dizziness, hyperventilation
HEART, NYSTAGMUS
All patients were assessed using the Dizziness Handicap Inventory (DHI). This is a self-report questionnaire to evaluate the effect that dizziness and unsteadiness have on emotional, functional, and physical aspects of daily living (Jacobson et al., The Italian version of the DHI is a reliable instrument, as indicated by a Cronbach’s alpha of 0.92 for the DHI total score, and of 0.82, 0.84, and 0.75 for the functional, emotional, and physical sub-scales, respectively (Nola et al., We decided to use biofeedback to voluntarily alter physiological parameters, respiratory rate in particular, because of the correlation between nystagmus and increased respiratory variability (Edlow et al., Explain the patient the physiology of breathing and overbreathing.Teach awareness of breathing, helping the patient pay attention to the emotions associated with effortless breathing.Teach slow and deep diaphragmatic breathing without feedback.Teach controlled diaphragmatic breathing with a ratio of 40:60 from inhalation to exhalation, with and without a pause between an exhalation and the next inhalation. In particular, the resonance frequency of the respiratory frequency is determined and diaphragmatic breathing is trained to the rhythm of the resonant frequency. During the training sessions, patients were taught to increase HRV according to the available protocols, in particular the protocol for Heart Rate Variability Biofeedback Training (Lehrer et al., Practice breathing at home, for 20 min twice a day, by training breathing with the second hand of a clock or resonant-frequency breathing rhythm downloaded from a computer; instruct the patient to be aware of symptoms of hyperventilation and, if it occurs, to breathe more shallowly and naturally.Furthermore, the experimental group underwent skin conductance biofeedback and EMG biofeedback according to the following indications (Khazan, 