Eye-tracking in amyotrophic lateral sclerosis: A longitudinal study of saccadic and cognitive tasks

Abstract

A relative preservation of eye movements is notable in ALS, but saccadic functions have not been studied longitudinally. ALS overlaps with FTD, typically involving executive dysfunction, and eye-tracking offers additional potential for the assessment of extramotor pathology where writing and speaking are both impaired. Eye-tracking measures (including anti-saccade, trail-making and visual search tasks) were assessed at six-monthly intervals for up to two years in a group of ALS (n = 61) and primary lateral sclerosis (n = 7) patients, compared to healthy age-matched controls (n = 39) assessed on a single occasion. Task performance was explored speculatively in relation to resting-state functional MRI (R-FMRI) network connectivity. Results showed that ALS patients were impaired on executive and visual search tasks despite normal basic saccadic function, and impairments in the PLS patients were unexpectedly often more severe. No significant progression was detected longitudinally in either group. No changes in R-FMRI network connectivity were identified in relation to patient performance. In conclusion, eye-tracking offers an objective means to assess extramotor cerebral involvement in ALS. The relative resistance of pure oculomotor function is confirmed, and higher-level executive impairments do not follow the same rate of decline as physical disability. PLS patients may have more cortical dysfunction than has been previously appreciated.

Altered cortical beta‐band oscillations reflect motor system degeneration in amyotrophic lateral sclerosis

“…Despite previous findings of reduced stop-signal ERPs [Thorns et al, 2010], no abnormalities in beta-band dynamics were noted in ALS patients, so that the changes in AGCs might represent very early compensatory neural changes. In contrast to an ERP study utilising the Stroop task [Amato et al, 2013], but in keeping with eye-tracking findings [Proudfoot et al, 2015], the present data suggest that executive control dysfunction may not spare PLS patients, given that task relevant functional connectivity was diminished between rIFC and SMA. Multiple nonexclusive biological and methodological restrictions may underlie the lack of correlation between the MEG data and cognitive profiles of the ALS participants , not least the brevity of the ECAS test as a opposed to more comprehensive and granular neuropsychological assessment.…”

“…The nosology of PLS continues to be debated [Le Forestier et al, 2001;Singer et al, 2007], although some clinical [Gordon et al, 2009;Pringle et al, 1992], neuroimaging [Agosta et al, 2014;Kolind et al, 2013;Kwan et al, 2013;M€ uller et al, 2012;Turner et al, 2007] and saccadic [Proudfoot et al, 2015] features support an apparent distinction from ALS. Involvement of the corpus callosum (CC) is a consistent feature of ALS [Filippini et al, 2010], thought to contribute to a functional impairment of interhemispheric inhibition, as evidenced by both TMS [Karandreas et al, 2007;Wittstock et al, 2007] and clinically evident mirror movements [Wittstock et al, 2011].…”

Eye‐tracking–based assessment suggests preserved well‐being in locked‐in patients

“…For qualitative analysis, we grouped answers as reported previously . An eye‐gaze–based version of the Trail Making Test part A and B (eTMT) was used to assess appropriate processing speed and executive cognitive functioning …”

Association of a Locus in theCAMTA1Gene With Survival in Patients With Sporadic Amyotrophic Lateral Sclerosis

“…30 The finding of a gene involved in cerebellar disease in ALS is not surprising given that trinucleotide repeat expansion in the ataxin 2 ( ATXN2 ) gene causes spinocerebellar ataxia or ALS, 31 the finding of C9orf72 pathologic mechanisms in the cerebellum of patients with ALS, 32 and the discovery of abnormal eye gaze in patients with ALS. 33,34 Increasing evidence suggests an association between ALS and cerebellar degeneration that is currently underrecognized, in the same way as the association between ALS and frontotemporal dementia remained undetected until recently.…”