ISSN : 2146-3123
E-ISSN : 2146-3131

Cut-Off Values For EEG Frequency in Differentiation of Alzheimer, Non-Alzheimer Dementia and Healthy Subjects: An Application of 3D-ROC Surface Method
Handan Ankaralı 1, Seyit Ankaralı 2, Fatih Mehmet Gökçe 3, Şerif Demir 3, Hulusi Keçeci 4
1Departments of Biostatistics, Medical Faculty of Zonguldak Karaelmas University, Zonguldak
2Departments of Physiology, Medical Faculty of Zonguldak Karaelmas University, Zonguldak
3Departments of Physiology, Medical Faculty of Düzce University, Düzce
4Departments of Neurology, Medical Faculty of Düzce University, Düzce
DOI : 10.5174/tutfd.2009.01528.2
Pages : 281-286


Objectives: To write a new macro programme for the use of the non-parametric 3-D Receiver Operating Characteristic (ROC) surface method in the discrimination of three or more groups, to study the usefulness of electroencephalography (EEG) frequency in the diagnosis of Alzheimer type dementia (AD), non-Alzheimer type dementia (NAD) and healthy subjects, and to determine cut-off values of EEG frequency.

Patients and Methods: The mean EEG frequencies in the left fontal region EEG records of subjects in the present study were calculated and the ROC surface method was used in discrimination of the groups.

Results: The volume under the ROC surface was calculated as 0.464±0.150. Accuracy of the mean frequency in differentiation of groups was statistically significant (p=0.024). 8 Hz was found to be convenient for differentiation of AD from NAD patients and 10 Hz for the differentiation of NAD patients and healthy subjects. The sensitivity was 87.5% for Alzheimer's dementia diagnosis and total accuracy was 65% using this cut-off pair.

Conclusion: We suggest that the mean EEG frequency may be used only as a pre-diagnostic tool for the differential diagnosis of these groups.

Keywords : Alzheimer type dementia; dementia; electroencephalography; diagnostic accuracy; volume under a ROC surface; classification

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