Clinical Characteristics of Patients with Persistent Apogeotropic and Persistent Geotropic Direction-Changing Positional Nystagmus

Background and Purpose 'this study aimed to determine the clinical features, diagnosis, and treatment of patients with persistent geotropic (pG) and persistent apogeotropic (pAG) direction-changing positional nystagmus (DCPN). Methods This retrospective study included 30 patients with pG-DCPN and 44 patients with pAG-DCPN. All patients underwent neurological and neurotological examinations, including an evaluation of gaze-evoked nystagmus, eye-movement tests, and assessments of limb ataxia and balance, as well as magnetic resonance imaging to exclude central causes. The characteristics of positional nystagmus were detected using the supine roll test (SRT) and bow-andlean test (BLT). The null point (NP) at which the nystagmus disappeared was determined. All patients were treated with the barbecue maneuver, and treatment efficacy was evaluated immediately, 1 week, and 1 month after treatment. Results The history of diseases associated with atherosclerosis, peripheral vestibular disorders, otological disease, and migraine differed significantly between patients with pG-DCPN and pAG-DCPN. The affected sides of persistent horizontal DCPN can be determined using the SRT and the BUT, while determining the second NP and vestibular function as well as performing an audiological evaluation can be used to assist in identifying the affected side. The efficacy rates immediately and 1 week after treatment with the barbecue maneuver were higher in patients with pAG-DCPN than in patients with pG-DCPN. Conclusions pG-DCPN was more compatible with the characteristics of cupulolithiasis, and pG-DCPN was more likely to be associated with a light cupula rather than canalolithiasis. pAG-DCPN was more likely to be accompanied by a disease associated with atherosclerosis, while pG-DCPN was often accompanied by autoimmune-related diseases and a history of migraine. The associations between pAG-DCPN, pG-DCPN, and the above-mentioned diseases need to be clarified further. The canalith-repositioning maneuver was effective in patients with pAG-DCPN and ineffective in patients with pG-DCPN, but most cases of pG-DCPN are self-limiting.