title: Power spectra for screening parkinsonian patients for mild cognitive impairment.
abstract: OBJECTIVE
  Mild cognitive impairment in Parkinson's disease (PD-MCI) is diagnosed based on the results of a standardized set of cognitive tests. We investigate whether quantitative EEG (qEEG) measures could identify differences between cognitively normal PD (PD-CogNL) and PD-MCI patients.
  
  
  METHODS
  High-resolution EEG was recorded in 53 patients with Parkinson's disease (PD). Relative power in five frequency bands was calculated globally and for ten regions. Peak and median frequencies were determined. qEEG results were compared between groups. Effect sizes of all variables were calculated. The best separating variable was used to demonstrate subject-wise classification.
  
  
  RESULTS
  Lower mean values were observed in global alpha1 power and alpha1 power in five brain regions (left hemisphere: frontal, central, temporal, occipital; right hemisphere: temporal, P < 0.05), differentiating between PD-CogNL and PD-MCI groups. Effect sizes were high, ranging from 0.79 to 0.87. Median frequency was 8.56 ± 0.74 Hz and was not different between the groups. The variable with the best subject-wise classification was the power in the alpha1 band in the right temporal region. The area under the corresponding receiver operating characteristic (ROC) curve was 0.72. The optimal classification threshold yielded a sensitivity of 65.9% and a specificity of 66.7%. The positive and negative predictive values were 87.1% and 36.4%, respectively.
  
  
  CONCLUSIONS
  Reduction in alpha1 band power in nondemented PD patients, particularly in the right temporal region, is highly indicative of MCI in PD patients. The results might be used to assist in time-efficient diagnosis of PD-MCI and avoid the drawbacks of test-retest effect in repeated neuropsychological testing.
authors.affiliation: Department of Neurology, Hospital of the University of Basel Petersgraben 4, 4031, Basel, Switzerland ; Swiss Tropical and Public Health Institute, University of Basel Socinstrasse 57, 4051, Basel, Switzerland.
authors.forename: Habib
authors.initials: H
authors.lastname: Bousleiman
authors.affiliation: Department of Neurology, Hospital of the University of Basel Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: Ronan
authors.initials: R
authors.lastname: Zimmermann
authors.affiliation: Department of Neurology, Hospital of the University of Basel Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: Shaheen
authors.initials: S
authors.lastname: Ahmed
authors.affiliation: Department of Neurology, Hospital of the University of Basel Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Hardmeier
authors.affiliation: Department of Neurology, Hospital of the University of Basel Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: Florian
authors.initials: F
authors.lastname: Hatz
authors.affiliation: Swiss Tropical and Public Health Institute, University of Basel Socinstrasse 57, 4051, Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
authors.affiliation: Department of Mathematics and Computer Science, University of Basel Bernoullistrasse 16, 4056, Basel, Switzerland.
authors.forename: Volker
authors.initials: V
authors.lastname: Roth
authors.affiliation: Department of Neurology, Hospital of the University of Basel Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: Ute
authors.initials: U
authors.lastname: Gschwandtner
authors.affiliation: Department of Neurology, Hospital of the University of Basel Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Fuhr