Noninvasive prediction of shunt operation outcome in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a syndrome characterized by gait disturbance, cognitive deterioration and urinary incontinence in elderly individuals. These symptoms can be improved by shunt operation in some but not all patients. Therefore, discovering predictive factors for the surgical outcome is of great clinical importance. We used normalized power variance (NPV) of electroencephalography (EEG) waves, a sensitive measure of the instability of cortical electrical activity, and found significantly higher NPV in beta frequency band at the right fronto-temporo-occipital electrodes (Fp2, T4 and O2) in shunt responders compared to non-responders. By utilizing these differences, we were able to correctly identify responders and non-responders to shunt operation with a positive predictive value of 80% and a negative predictive value of 88%. Our findings indicate that NPV can be useful in noninvasively predicting the clinical outcome of shunt operation in patients with iNPH

Image_2_Boundary EEG Asymmetry Is Associated to Linguistic Competence in Vascular Cognitive Impairments.JPEG

<p>Background and Purpose: We recently noted a gradual change in the boundary electroencephalography (EEG) oscillation of 7.8 Hz between theta (θ) and alpha (α) bands in response to increased atherosclerosis levels in the elderly. The aim of this study was to investigate the role of boundary EEG oscillations of θ-α bands on cognitive functions in vascular cognitive impairments (VCI) patients.</p><p>Materials and Methods: We examined 55 patients with VCI in carotid stenosis, and underwent EEG in a resting state with closed eyes for 5 min. The asymmetry index (AI) along homologous channel pairs (e.g., F7-8) was assessed using neuronal activity topography (NAT). AI referring to 10 frequency components ranging from 4 to 20 Hz and neuropsychological assessments including linguistic competence were analyzed.</p><p>Results: The main findings was that the language score had a positive association with AI in 7.8 Hz at F7-8 and a negative association with AI in 6.3 Hz at C3-4 and 14.1 Hz at F3-4.</p><p>Conclusion: EEG asymmetry in a boundary range might have a special role in linguistic competence, suggesting the application of neural oscillation on the cognitive function evaluation and neurorehabilition induced by a frequency-specific transcranial alternating current stimulation.</p

Altered Neuronal Activity Topography Markers in the Elderly with Increased Atherosclerosis

Background: Previously, we reported on vascular cognitive impairment (VCI) templates, consisting of patients with VCI associated with carotid stenosis (&gt;60%) using a quantitative electroencephalographic (EEG) technique called neuronal activity topography (NAT). Here using the VCI templates, we investigated the hypothesis that internal carotid artery–intima-media thickness (ICA–IMT) is associated with EEG spectrum intensity (sNAT) and spectrum steepness (vNAT).Methods: A total of 221 community-dwelling elderly subjects were recruited. Four groups were classified according to quartiles of ICA–IMT as assessed by ultrasonography: control group A, normal (≤0.9 mm); group B, mild atherosclerosis (1−1.1 mm); group C, moderate atherosclerosis (1.2−1.8 mm); and group D, severe atherosclerosis (≥1.9 mm). EEG markers of power ratio index (PRI), and the binary likelihood of being in the VCI group vs. the that of being in control group A (sLx:VCI−A, vLx:VCI−A) were assessed, respectively. Differences in mean total scores for PRI, sLx:VCI−A, vLx:VCI−A, between control group A and the other groups were compared using Dunnett's test, respectively.Results: The mean total scores of the PRI were 3.25, 3.00, 2.77, and 2.26 for groups A, B, C, and D, respectively. There was a significant decrease in the PRI in group D compared with group A (P = 0.0066). The mean total scores of the sLx:VCI−A were −0.14, −0.11, −0.1, and −0.03 for groups A, B, C, and D, respectively. The sLx:VCI−A in group D was significantly higher compared to that in group A (P &lt; 0.0001). The mean total scores of the vLx:VCI−A were −0.04,−0.01, 0.01, and 0.06 for group A, B, C, and D, respectively. The vLx:VCI−A in group D and group C was significantly higher compared to that in group A, respectively (P &lt; 0.0001, P = 0.02).Conclusion: Community-dwelling elderly subjects in the increased carotid atherosclerosis of ICA–IMT (≥1.9 mm) were at greatest risk of an EEG change as assessed by NAT