Postural control in horizontal benign paroxismal positional vertigo

Sixteen patients affected by benign paroxysmal positional vertigo of the horizontal semicircular canal (BPPV-HSC) were investigated by means of dynamic posturography (DP) and during bithermal caloric stimula- tion. Data were compared to data from 40 patients with benign paroxysmal positional vertigo of the posterior semicircular canal (BPPV-PSC) and 20 healthy controls. No postural deficit was observed before or after a libera- tive Lempert’s manoeuvre when patients were compared to control subjects. BPPV-PSC postural scores were sig- nificantly impaired compared to scores from the BPPV- HSC group. A residual significant postural impairment was also observed after a successful liberative manoeuvre in the BPPV-PSC group. Electronystagmographic record- ings before recovery revealed significant hypoexcitability of the affected ear in 8/16 patients of the BPPV-HSC group. After the liberative manoeuvre, a symmetric bilat- eral response to caloric stimulation was recorded in all pa- tients. Three main conclusions can be drawn from the pre- sent data. First, disorders of the horizontal semicircular canal do not change postural control. Second, dynamic posturography can detect the postural imbalance due to posterior semicircular canal dysfunction even after resolu- tion of paroxysmal vertigo attacks. Third, utricular dys- function can be ruled out as a cause of the residual pos- tural deficit observed in BPPV-PSC patients. Therefore the recovery delay observed even 1 month after the liber- ative manoeuvre in the BPPV-PSC-group might be due to the persistence of small amounts of residual debris in the canal, to paralysis of ampullar receptors, or to the time needed for central vestibular re-adaptation