Abstract
It has been considered that both ageotropic and geotropic direction-changing nystagmus frequently arise from central lesions, but lately, reports showing that direction-changing positional nystagmus is induced by peripheral lesions have increased. This study was designed to investigate the clinical features of horizontal canal variants of paroxysmal positional vertigo (HC-PPV). A retrospective study of 151 patients with HC-PPV was done. Patients complained of positional vertigo associated with direction-changing horizontal positional nystagmus, and either geotropic or ageotropic were examined. Horizontal nystagmus was triggered in all patients when rolled to either side in a supine position. The patients were 44 men and 107 women ranging from 24 to 88 years old (average 58.2 years old). The nystagmus was geotropic in 75 and ageotropic in 76 patients. There were many cases without latency in ageotropic cases, whereas there was latency in geotropic cases. As for the duration of the nystagmus, many ageotropic cases lasted more than one minute, whereas in many geotropic cases, the duration of nystagmus was less than one minute. Pure horizontal nystagmus was observed in most ageotropic cases, but in most geotropic cases, horizontal nystagmus with a torsional component was observed. Autotherapy was given to both geotropic and ageotropic cases. Geotropic cases tended to be cured in a short period compared with ageotropic cases, but some cases needed a longer time to cure in both groups. The “barbecue rotation” maneuver for treatment was performed in some cases. The effect of this maneuver was not so good as the Eply maneuver for BPPV.
