Specific saccade deficits in patients with Alzheimer’s disease at mild to moderate stage and in patients with amnestic mild cognitive impairment

Abstract

Saccadic impairment in Alzheimer's disease (AD) was found in horizontal saccades. The present study extends investigation to vertical saccades in a large number of subjects, including AD and amnestic mild cognitive impairment (aMCI). We examined both horizontal and vertical saccades in 30 healthy elderly, 18 aMCI, and 25 AD. Two tasks were used: gap (fixation target extinguishes prior to target onset) and overlap (fixation stays on after target onset). Eye movements were recorded with the Eyeseecam system. (1) Robust gap effect (shorter latencies in gap than in overlap) exists for AD and aMCI patients as for healthy elderly; (2) abnormal long latency of saccades in gap and overlap tasks for AD relative to healthy elderly and aMCI patients; (3) longer latency for aMCI patients than for healthy elderly for the overlap task; (4) significant correlation between scores of Mini-Mental State Examination (MMSE) and latencies of saccades considering the AD group only; (5) higher coefficient of variation in latency for AD patients than for healthy elderly and for aMCI patients; (6) variability of accuracy and speed is abnormally higher in AD patients than in aMCI and healthy elderly. Abnormalities of latency and latency-accuracy-speed variability reflect deficits of cerebral areas involved in the triggering and execution of saccades; latency of saccades can be used as follow-up test for aMCI and AD patients with its significant correlation with the changes of MMSE scores.

Distinctive features of microsaccades in Alzheimer’s disease and in mild cognitive impairment

“…4, Table 1). This finding is consistent with the lack of brainstem oculomotor function impairment in MCI or AD patients with mild to moderate severity of disease (Garbutt et al 2008;Yang et al 2011Yang et al , 2013; but see Simic et al 2009).…”

“…A more recent study found no effects of normal aging on saccade velocity, however, even for saccadic amplitudes of 20° (Munoz et al 1998). Two recent studies have moreover found normal saccadic velocities in AD and MCI (Yang et al 2011(Yang et al , 2013.…”

“…Saccadic gain and speed findings in AD are controversial: some studies found impairment (Fletcher and Sharpe 1986;Hotson and Steinke 1988;Shafiq-Antonacci et al 2003) whereas others did not (Moser et al 1995;Garbutt et al 2008). Very few studies have examined saccadic eye movements in MCI (Yang et al 2011(Yang et al , 2013, and no research has examined the characteristics of microsaccades in either AD or MCI.…”

On the early diagnosis of Alzheimer's Disease from multimodal signals: A survey

“…Some researches have revealed that AD patients show higher latency than healthy subjects when starting prosaccades [223][224][225][226], that the velocity of these prosaccades is lower [226] and that the accuracy when reaching the target also worsens [220]. Antisaccades have also been analysed in some researches.…”

Classification of user performance in the Ruff Figural Fluency Test based on eye-tracking features

“…Performance of the saccadic eye movement was found to be a sensitive marker for even minor impairment of cerebral function in various physiological and pathological conditions, including sleep deprivation [18], early Alzheimer's [19], extra-motor cerebral pathology [13] and cognitive frontal alterations [20,21] …”