Isolated horizontal positional nystagmus from a posterior fossa lesion

Abstract

Isolated vertigo with horizontal positional nystagmus as an impending sign of a central lesion has rarely been reported. Here we present neuro-otologic findings of patients with these clinical signs. Lesion overlays from 6 patients with ageotropic positional nystagmus revealed that the nodulus and vermis are common areas of injury. In contrast, 2 patients with geotropic positional nystagmus had cerebellar peduncle and lateral medullary lesions. These clinical findings suggest that vertigo with horizontal positional nystagmus, even in the absence of other initial neurological signs, may indicate a posterior fossa lesion, including that in the nodulus, vermis, and deep cerebellar structures.

Central Positional Nystagmus: A Systematic Literature Review

“…Although 33 patients (80.5%) presented with exclusively positional horizontal nystagmus (pHN) upon supine roll, this was not present to both sides in 9 (23.1%) (7,18,32) and was direction-reversing while the position was maintained in 1 (2.6%) (15), therefore, considered atypical of lateral canal BPPV. Lee et al (35) did not report whether the pHN was present to both left and right head positions, or just one, in his patients. Of the eight, Lee et al report six (75%) with ageotropic and two (25%) with geotropic pHN.…”

“…PN was quantified in 51 (62.1%) participants, 35 (42.7%) with VNG (4,15,(20)(21)(22)(23)(24)(25)(26)35), 15 (18.3%) with electronystagmography (11,14,18,33), and 1 (1.2%) using three-dimensional scleral induction coil (6). It is uncertain how the nystagmus was recorded in the remaining 31 participants (37.8%), presumably from direct observation during clinical examination (6,7,12,13,16,17,19,(30)(31)(32)(33)(34).…”

“…The study set included 11 case series (6,7,11,26,(30)(31)(32)(33)(34)(35)(36) and 17 case reports (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(27)(28)(29). This review did not identify any controlled studies relevant to the diagnosis of central positional vertigo/nystagmus.…”

“…These included gait unsteadiness (n = 23) (6, 15-18, 22, 23, 25, 27, 30, 33) with falls (n = 3) (7, 31), headache (n = 7) (31,32,34,35), motor weakness (n = 4) (6,16,32), clumsiness of extremities (n = 3) (18, 31), unexpected weight loss (n = 2) (14, 32), diplopia (n = 2) (20, 32), asymmetrical hearing loss (n = 4) (28,29,32,35), facial numbness (n = 2) (6, 35), slurred speech (n = 1) (16), dysphagia (n = 1) (35), oscillopsia (n = 2) (28, 32), visual blurring (n = 1) (12), and loss of taste (n = 1) (32).…”

“…In 61 participants (74.4%), there was cerebellar involvement (4, 6, 7, 11-17, 21-23, 26-35). Seven participants (8.5%) had isolated brainstem lesions (6,19,20,22,23,35), and 12 participants (14.6%) had lesions involving the fourth ventricle (11,13,26,33,34). In five participants (6.1%), lesions were "diffuse" (16,18) or unspecified (7).…”