Impaired preconscious auditory processing and cognitive functions in Alzheimer's disease.
OBJECTIVE
To study whether preconscious auditory processing is deteriorated in patients with Alzheimer's disease (AD) having mild to moderate cognitive symptoms. To investigate whether auditory processing correlates with the impairment of the higher cortical functions.


METHODS
P50m and N100m responses elicited by a sequence of repetitive tones were recorded with a whole-head magnetometer from 22 patients with probable AD and from 18 healthy age-matched controls. In addition, an extensive neuropsychological test battery assessing main cognitive domains was administered to all subjects.


RESULTS
The patients with AD had significantly delayed N100m responses in the left hemisphere that correlated with the impairment of the language functions.


CONCLUSIONS
N100m auditory responses measured with magnetoencephalography may be useful in evaluating the severity and progression of the cortical dysfunction in dementia.
Pekkonen
E
E
Department of Neurology, Helsinki University Central Hospital, Finland. eero@biomag.helsinki.fi
Jääskeläinen
I P
IP
Hietanen
M
M
Huotilainen
M
M
Näätänen
R
R
Ilmoniemi
R J
RJ
Erkinjuntti
T
T
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000503:physiopathology*; D001308:Auditory Perceptual Disorders / Q000209:etiology / Q000503:physiopathology*; D004585:Electrooculography; D005072:Evoked Potentials, Auditory; D005260:Female; D007839:Functional Laterality; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales