P122. Alpha1/theta ratio from quantitative EEG (qEEG) as a reliable marker for mild cognitive impairment (MCI) in patients with Parkinson's disease (PD). Issue 8 (August 2015)

• Record Type: Journal Article
• Authors: Bousleiman, H.; Chaturvedi, M.; Gschwandtner, U.; Hatz, F.; Schindler, C.; Zimmermann, R.; Fuhr, P.
• Is Part Of: Clinical neurophysiology. Volume 126:Issue 8(2015:Aug.)
• Page Start: e150
• Page End: e151
• Publication Date: 2015-08
• Subjects: Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2015.04.249
• Languages: English
• ISSNs: 1388-2457

Abstract

<abstract xml:lang="en" abstract-type="author" id="ab005"> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title id="st005">Objective</title> <p id="sp005">We investigated whether a combination of qEEG variables, in particular signal power in the alpha1 (8–10 Hz) and theta (4–8 Hz) bands, could represent a robust marker for MCI in patients with PD.</p> </sec> <sec> <title id="st010">Background</title> <p id="sp010">MCI is diagnosed based on the results of a large standardized set of cognitive tests. Certain qEEG parameters are associated with dementia. Previous studies demonstrated a relation between MCI in PD patients and alpha1 power (<xref id="c0005" rid="b0005">Bousleiman et al., 2014</xref>). Other studies introduced a ratio between alpha and theta powers and demonstrated its association with Alzheimer's disease (<xref id="c0010" rid="b0010">Schmidt et al., 2013</xref>).</p> </sec> <sec> <title id="st015">Methods</title> <p id="sp015">High-resolution 256-channel EEG were recorded in 43 PD patients (MCI/non-MCI: 18/25 ∣age: 68.1 ± 7.9∣ female/male: 16/27). The data was pre-processed semi-automatically and global relative power in alpha1 and theta bands was calculated. Follow-up recordings at four weeks (4W) and six months (6 M) were collected for 32 patients (MCI/non-MCI: 13/19) to test the stability over time. Results were compared between groups using permutation tests on t-statistics to correct for multiple comparisons. Effect sizes (ES) and intra-class correlation (ICC) were calculated.</p> </sec> <sec> <title id="st020">Results</title> <p id="sp020">An increase (<italic>p</italic> = 0.017; ES = 0.789) in the theta and a decrease (<italic>p</italic> = 0.042; ES = 0.782) in the alpha1 signal power were associated with MCI in PD patients. The ratio alpha1/theta showed a more robust negative association (<italic>p</italic> = 0.012; ES = 1.04) than those calculated for each variable separately. Moreover, the ratio was stable over time (4 W: <italic>p</italic> = 0.002; ES = 1.082 – 6 M: <italic>p</italic> = 0.002; ES = 1.084 – ICC = 0.76). Patients whose baseline positive MCI diagnosis did not change at 6 M exhibited a higher ratio than those with a negative MCI diagnosis at 6 M. However, the difference was not statistically significant (<italic>p</italic> = 0.1178).</p> </sec> <sec> <title id="st025">Conclusions</title> <p id="sp025">Reduction of the alpha1/theta ratio is reliably associated with MCI in PD patients. This finding might be used as a robust marker for screening PD patients for early cognitive deficits.</p> </sec> </abstract>