Long-term follow-up of benign positional vertical opsoclonus in infants: retrospective cohort.

Background/aims: Benign positional vertical opsoclonus in infants, also described as paroxysmal tonic downgaze, is an unsettling phenomenon that leads to extensive work-up, although benign course has been reported in sporadic cases. We describe long-term follow-up of a series of infants with the phenomenon.

Methods: This retrospective cohort included all infants diagnosed with rapid downgaze eye movement in 2012-2015 and followed until 2016. The databases of two medical centres were retrospectively reviewed. Benign positional vertical opsoclonus was diagnosed based on clinical findings of experienced neuro-ophthalmologists. Data were collected on demographics, symptoms and signs, neuro-ophthalmological and neurological evaluations, and outcome. Imaging studies were reviewed. Main outcome measures were long-term outcome and findings of the thorough investigation.

Results: The cohort included six infants. All infants were born at term. Age at presentation was several days to 12 weeks. Episodes lasted a few seconds and varied in frequency from <10 to dozens per day. In five infants, symptoms occurred in the supine position. There was a wide variability in the work-up without any pathological findings. Follow-up ranged from 1 to 2.5 years. Ocular symptoms gradually decreased until resolution. Infants reached normal developmental milestones.

Conclusions: Our identification of six patients in only 3 years suggests benign positional vertical opsoclonus may be more prevalent than previously described. In our experience, it affects otherwise healthy infants and resolves spontaneously. In view of the good long-term outcome, a comprehensive clinical investigation may not be necessary.