TY - JOUR
T1 - Temporal frequency deficit in patients with senile dementia of the Alzheimer type
T2 - A visual evoked potential study
AU - Tobimatsu, Shozo
AU - Hamada, T.
AU - Okayama, M.
AU - Fukui, R.
AU - Kato, M.
PY - 1994/7
Y1 - 1994/7
N2 - To study the temporal aspect of visual processing of senile dementia of the Alzheimer type (SDAT), we recorded the steady-state visual evoked potentials (VEPs) to LED goggle stimulation at five different temporal frequencies in 14 patients with SDATand 14 control subjects. For comparison, we also studied 14 patients with vascular dementia (VD).All subjects were women, and their ages were closely matched. Temporal frequencies were 5, 10, 15, 20, and 30 Hz. The steady-state VEPs were Fourier analyzed, and both the amplitude and phase of the first and second harmonic responses were obtained. There was a significant difference in the amplitude across the three groups for stimulation at 15, 20, and30 Hz, but no difference at a stimulation of 5 and 10 Hz. Multiple comparison tests revealed that patients with SDAT had a significantly smaller amplitude than normal controls.Patients with VD had lower amplitudes than normal subjects, but this was not statisticallysignificant. In the phase data, there were also no statistically significant differences across the three groups for any of the temporal frequencies. These results indicate that atemporal frequency deficit exists in SDAT. This phenomenon may be explained by the pathology that affects the early stage of visual signal processing.
AB - To study the temporal aspect of visual processing of senile dementia of the Alzheimer type (SDAT), we recorded the steady-state visual evoked potentials (VEPs) to LED goggle stimulation at five different temporal frequencies in 14 patients with SDATand 14 control subjects. For comparison, we also studied 14 patients with vascular dementia (VD).All subjects were women, and their ages were closely matched. Temporal frequencies were 5, 10, 15, 20, and 30 Hz. The steady-state VEPs were Fourier analyzed, and both the amplitude and phase of the first and second harmonic responses were obtained. There was a significant difference in the amplitude across the three groups for stimulation at 15, 20, and30 Hz, but no difference at a stimulation of 5 and 10 Hz. Multiple comparison tests revealed that patients with SDAT had a significantly smaller amplitude than normal controls.Patients with VD had lower amplitudes than normal subjects, but this was not statisticallysignificant. In the phase data, there were also no statistically significant differences across the three groups for any of the temporal frequencies. These results indicate that atemporal frequency deficit exists in SDAT. This phenomenon may be explained by the pathology that affects the early stage of visual signal processing.
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U2 - 10.1212/wnl.44.7.1260
DO - 10.1212/wnl.44.7.1260
M3 - Article
C2 - 8035926
AN - SCOPUS:0028122058
VL - 44
SP - 1260
EP - 1263
JO - Neurology
JF - Neurology
SN - 0028-3878
IS - 7
ER -