The use of eye‐movement recording in patients with anti‐Hu antibody–associated paraneoplastic neurological syndromes to objectively determine extent and course of disease

BACKGROUND AND PURPOSE: Paraneoplastic neurological syndromes with Hu‐antibodies (Hu‐PNS) are immune‐mediated disorders in patients with malignancies, most frequently small cell lung cancer, affecting both the peripheral and central nervous system (CNS). In Hu‐PNS, brainstem and cerebellar involvement are common. Here, we assessed whether eye‐movement disturbances can be used for diagnosis and monitoring of CNS involvement in Hu‐PNS. METHODS: Twenty‐nine patients with Hu‐PNS (17 females; mean age, 63.2 years,) and 14 healthy age‐matched controls (seven females; mean age, 60.2 years) were included. Saccadic and smooth pursuit eye movements in response to visual stimuli were recorded with video‐oculography. Eye movements were scored quantitatively (number of correction saccades, saccadic intrusions, and saccades during fixation period) and qualitatively by two eye‐movement experts. In 20 patients, up to three follow‐up measurements were made during subsequent hospital visits with fixed 4‐week intervals. Disease course was assessed using the modified Rankin Scale. RESULTS: Eye movements were disturbed in 26 of 29 Hu‐PNS patients, with horizontal eye movements being in general more impaired. Moreover, in 12 of the 14 Hu‐PNS patients without clinical CNS involvement, eye movements were disturbed. Changes in eye‐movement control over a period of up to 12 weeks were significantly correlated with the clinical response to treatment (ρ = 0.52, p = 0.02). CONCLUSIONS: Hu‐PNS often affects eye‐movement control, also in the absence of CNS signs or symptoms. Eye‐movement recordings in Hu‐PNS patients might be a useful tool to objectively monitor progression and treatment efficacy in Hu‐PNS patients.