Early saccades in amyotrophic lateral sclerosis

Abstract

Our objective was to correlate saccadic abnormalities, including early saccades, in patients with amyotrophic lateral sclerosis (ALS) with measures of motor and functional impairment. A portable saccadometer was used to record saccades in ALS patients and control subjects. The linear approach to threshold with ergodic rate model was used to characterize saccades, including sub-populations of early saccades. Patients with established cognitive impairment or frontotemporal dementia were excluded. Limb-onset (Limb ALS) and bulbar-onset (Bulbar ALS) patient groups were compared and saccadic abnormalities were correlated with measures of motor and functional impairment. In total, 48 participants were included in the study; 24 patients with ALS (15 males, 9 females; mean age 57.0 +/− 13.9 years; mean symptom duration 22.4 +/− 16.3 months, of whom 62.5% had Limb ALS) and 24 age-matched controls. Early saccades were increased in both Limb ALS and Bulbar ALS patients, but other saccadic parameters were normal in ALS. Saccadic abnormalities did not correlate with motor or functional impairment. In conclusion, ALS patients show increased early saccades, but exhibit no significant differences across ALS phenotypes.

Key words::

• ALS
• saccades
• early saccades

Acknowledgements

JRB gratefully acknowledges funding support from the National Health and Medical Research Council of Australia, the Motor Neuron Disease Research Institute of Australia, and the Australian Research Council. MK and JRH are supported by a National Health and Medical Research Council Program Grant. JRH is supported by an Australian Research Council Federation Fellowship.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.