Clinical and electrophysiological results of eye muscle surgery in 17 patients with downbeat nystagmus

Two-muscle surgical treatment of a compensatory head tilt in an adult with acquired downbeat nystagmus

Kestenbaum-Anderson-like operations have proven beneficial in treatment of compensatory head tilt in patients with infantile nystagmus. However, their use in acquired vertical nystagmus in adults with head tilt has rarely been reported. Presented here is a case of a 52-year-old woman with acquired downbeat nystagmus with a significant head tilt who responded to a simple two-muscle surgery involving the superior recti. Cyclovertical muscle surgery should be considered a viable option in such patients who are refractory to medical intervention. Additionally, it appears that four-muscle vertical muscle recessions (two muscles per eye) may not be necessary to dampen vertical nystagmus since good results can be obtained with a single muscle recession bilaterally.

Downbeat nystagmus: a clinical review of diagnosis and management

PURPOSE OF REVIEW

This review will extensively cover the clinical manifestations, causes, diagnostic evaluation, and management strategies of downbeat nystagmus (DBN).

RECENT FINDINGS

Historically, MRI to assess for structural lesions at the cervicomedullary junction has been the primary diagnostic test in the evaluation of DBN since the 1980s. In recent years, there is increasing awareness of nonstructural causes of DBN including gluten ataxia, nutritional deficiencies, and paraneoplastic syndromes, among others. Medical management with aminopyridines has become first-line therapy in addition to disease-specific therapies.

SUMMARY

DBN is a common form of acquired nystagmus and the differential diagnosis remains broad, including both benign and potentially fatal causes. For practical purposes, the causes can be categorized as structural vs. nonstructural with MRI as the ideal, initial diagnostic study to differentiate the two. General therapeutic options include pharmacotherapy to enhance Purkinje cell function, strabismus surgery or prisms to shift null points, and behavioural changes. Disease-specific treatment is necessarily broad, though a significant proportion of patients will be idiopathic.

Reading Performance and Compensatory Head Posture in Infantile Nystagmus after Null Zone Training

This study aimed to assess the visual function, reading performance, and compensatory head posture (CHP) in schoolchildren with infantile nystagmus. A total of 18 participants aged between 13 to 18 years old were divided into spectacle (n = 9) and null zone group (n = 9) based on their visual acuity. Visual acuity (LogMAR), contrast sensitivity (Pelli–Robson), reading time and rate (Tobii TX300), and CHP were measured pre and post null zone reading training. Participants in the null zone group received 10 sessions of training (5 weeks). Visual acuity and contrast sensitivity of participants in the spectacle and null zone groups were not significantly different pre and post training. Reading performance, i.e., reading time (z = −1.36; p = 0.173) and reading rate (z = −0.06; p = 0.953), of participants in the spectacle group was not significantly different after 5 weeks. Reading time (z = −2.55; p = 0.011) and reading rate (z = −2.07; p = 0.038 of participants in the null zone group showed significant improvement post training. After 5 weeks, CHP improved in six out of the nine participants (66.7%) of the null zone group and was unchanged in all participants in the spectacle group. Null zone reading training could benefit children with infantile nystagmus in improving reading performance and compensatory head posture.