Subjective visual vertical deviation in patients with early-onset direction-changing horizontal positional nystagmus

• Published in: Auris, nasus, larynx Vol. 50; no. 1; pp. 48 - 56
• Main Author: Shigeno, Kohichiro
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2023
• Subjects: Apogeotropic; Benign Paroxysmal Positional Vertigo; Geotropic; Humans; Lateral semicircular canal; Light cupula; Nystagmus, Pathologic; Nystagmus, Physiologic; Otolaryngology; Semicircular Canals; Subjective visual vertical; Utricle; Vestibular Diseases; Vestibular Function Tests; Lateral semicircular canal; Geotropic; Apogeotropic; Subjective visual vertical; Utricle; Light cupula; Benign paroxysmal positional vertigo
• DOI: 10.1016/j.anl.2022.05.003
• ISSN: 0385-8146; 1879-1476

Otolithic dysfunction is investigated in cases of direction-changing horizontal positional nystagmus (DCHPN) due to peripheral vestibular disorders. The static-subjective visual vertical (S-SVV) was conducted in DCHPN cases within 48 h after onset. The absolute values of S-SVV deviations of patients with Light cupula and lateral canal-benign paroxysmal positional vertigo-cupulolithiasis (L-BPPV-Cup) were significantly different from those of healthy subjects (p < 0.001, p < 0.05, respectively), whereas there were no significant differences in those of patients with L-BPPV-Canalolithiasis-geotropic (L-BPPV-Can-g) or L-BPPV-Can-ageotropic (L-BPPV-Can-a) versus healthy subjects. Significant differences were found in S-SVV (+: deviation to the affected side, −: deviation to the unaffected side) between patients with Light cupula and those with L-BPPV-Can-g, L-BPPV-Can-a and L-BPPV-Cup (p < 0.01, p < 0.05, and p < 0.001, respectively), as well as between those with L-BPPV-Can-g and L-BPPV-Cup (p < 0.01). The S-SVV in patients with Light cupula, L-BPPV-Can-g, and L-BPPV-Can-a deviated more to the affected side, whereas that in patients with L-BPPV-Cup deviated more to the unaffected side. Mild otolithic dysfunctions were found in patients with DCHPN due to the presence of peripheral vestibular disorders within 48 h after onset. The extent of otolithic (utricular) disorders in patients with DCHPN is estimated in decreasing order as follows: Light cupula > L-BPPV-Cup > L-BPPV-Can-g and L-BPPV-Can-a. Many patients with L-BPPV-Cup likely suffer from disorders of the pars externa of the utricular macula, whereas many patients with L-BPPV-Can-g likely suffer from disorders of the pars interna of the utricular macula. L-BPPV-Can-a and L-BPPV-Can-g must be induced by a common mild utricular disorder.