Impairment of oculomotor functions in patients with early to advanced amyotrophic lateral sclerosis

Research output: Contribution to journalResearch articleContributedpeer-review



Amyotrophic lateral sclerosis (ALS) can result into an incomplete locked in state (iLIS), in which communication depends on eye tracking computer devices. Oculomotor function impairments in ALS have been reported, but there is little research, particularly with respect to patients in iLIS. In the present study, we compared reflexive and executive oculomotor function by means of an eye tracking test battery between three groups: advanced ALS patients in iLIS (n = 22), patients in early to middle ALS stages (n = 44) and healthy subjects (n = 32). Patients with ALS showed significant deteriorations in oculomotor functions, with stronger impairments in iLIS. More specifically, ALS patients produced visually guided prosaccades with longer latencies and more frequent hypometria compared to healthy subjects. Longest latencies were obtained in iLIS patients, with a stronger prolongation for vertical than for horizontal prosaccades. ALS patients made more antisaccade errors and generated antisaccades with longer latencies. Smooth pursuit was also impaired in ALS. In the earlier ALS stages, bulbar onset patients presented stronger antisaccade and smooth pursuit deficits than spinal onset patients. Our findings reveal a relevant deterioration of important oculomotor functions in ALS, which increases in iLIS. It includes impairments of reflexive eye movements to loss of executive inhibitory control, indicating a progressing pathological involvement of prefrontal, midbrain and brainstem areas. The assessment of oculomotor functions may therefore provide clinically relevant bio- and progression marker, particularly in advanced ALS.


Original languageEnglish
Pages (from-to)325-339
Number of pages15
JournalJournal of neurology
Issue number1
Publication statusE-pub ahead of print - 15 Sept 2023

External IDs

ORCID /0000-0002-6673-9591/work/142659375
Scopus 85171273609
Mendeley ab6cd070-29bd-3413-8c32-727a11188e74


ASJC Scopus subject areas


  • Amyotrophic lateral sclerosis, Executive function, Eye movements, Eye tracking communication systems, Oculomotor function, Saccades, Pursuit, Smooth, Amyotrophic Lateral Sclerosis, Eye Movements, Humans

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