Background:
Classified as saccadic intrusions, Square-Wave Jerks (SWJs) have been observed
during Visual Fixation (VF) in Alzheimer’s Disease (AD). However, the pathological significance
of this phenomenon remains unclear.
Objective:
The present study analyzed the characteristics of SWJs in patients with AD with their eyes
open in the dark without VF.
Methods:
Fifteen patients with AD and 15 healthy age- and sex-matched controls were investigated and
compared. Saccadic intrusions with and without VF were detected as SWJs and measured using an electronystagmogram.
Results:
No significant difference in the frequency of SWJs was observed between control and AD
groups with VF, but significantly more SWJs were observed in the AD group than in the control group
in the absence of VF (p<0.01). In the control group, the frequency of SWJs was significantly higher with
VF as compared to without VF. Conversely, the frequency in the AD group was significantly higher
without VF. Furthermore, a directly proportional relationship was observed between the frequency of
SWJs and higher-order function (R>0.55) in the AD group.
Conclusion:
SWJs without VF may have pathological significance in AD. In healthy individuals, SWJs
are generated by VF and suppressed without VF. Conversely, in AD, SWJs are generated rather than
suppressed in the absence of VF. These pathognomonic SWJs without VF also appear to be correlated
with higher-order dysfunction, reflecting AD-related cortical damage. These findings suggest that pathological
SWJs without VF observed in AD derive from cortical damage and may constitute an important
marker of a higher-order function.
Higher Order Function Networks for View Planning and Multi-View Reconstruction
