Alzheimer Tipi Demansta İç ve Dış Kaynaklı Dikkat: Konum Etkisi

Funda SALMAN, Banu CANGÖZ, Erguvan Tuğba ÖZEL KIZIL
2019; 30(3): 172-179
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Endogenous and Exogenous Attention in Alzheimer Type of Dementia: Effect of Target Position

Objective: Endogenous attention (EnA) is an ability in goal-driven
processes, controlled by top-down mechanisms and exogenous attention
(ExA) is an ability in stimulus-driven processes, controlled by bottomup mechanisms. In the present research, it was aimed to investigate
in Alzheimer’s disease (AD) the EnA and ExA processes in relation to
target position (right/left) by using the Spatial Cueing Paradigm (SCP).
Method: The study was conducted with the participants of 65-90 year
age range, consisting of 14 female and 14 male (n=28) participants
diagnosed with AD and 12 female and 12 male (n=24) healthy
volunteers as controls. The group variable (AD, Control) was tested on
the intergroup basis; and the attention type (EnA, ExA), trial type (valid
/VT+ and invalid/ VT-) and the target position (left/right) variables
were tested on the intra-subject basis (within subject design). Two
separate factorial ANOVAs were conducted for mean reaction time and
accuracy measures obtained from SCP.
Results: In comparison to the control group, the AD group participants
gave slow and wrong reactions to stimuli for EnA and ExA. The AD
group responses were faster in the VT+s and more accurate in the
VT-s to stimuli on the left as compared to those on the right; and the
responses of AD patients to the stimuli on the left as compared to those
on the right was more accurate in VT-s under ExA condition.
Conclusion: AD causes impairment of EnA and ExA. Faster reactions
by AD participants to the target on the left in VT+s and more accurate
reactions to the target on the left in VT-s are in agreement with reports
in the literature on the lateralization of visual-spatial attention (VSA)
in the right hemisphere. In this study, also in agreement with previous
reports, lateralization in AD was noted in favour of the stimuli on the
left in ExA.
Key Words: Alzheimer’s disease, attention, right hemisphere, lateralization