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To compare event-related oscillations in patients with dementia with Lewy bodies (DLB) who are carriers and non-carriers of glucocerebrosidase (GBA) mutations.EEG was recorded during a visual oddball task in eight Ashkenazi Jewish DLB patients with the N370S mutation in theGBAgene (GBA-DLB) and eleven DLB non-carriers. The time-frequency power and inter-trial phase clustering were calculated from the Morlet wavelet convolution for the midline electrodes.Task performance and cognitive assessments were comparable between groups. While the within-non-GBA-DLB group analysis revealed delta-band power synchronization relative to the baseline (p = 0.01, Cohen's d = 1.0), the within-GBA-DLB-group analysis detected no event-related changes in power. Both groups showed an increase relative to the baseline in the delta and theta bands inter-trial phase clustering (all p 0.03, d 1.3). The between-group analysis revealed that event-related power - but not clustering - was lower in GBA-DLB compared to non-carriers in the delta band at Fz and Cz (p = 0.04, d = -0.9).GBA-DLB patients showed decreased delta-band power compared to non-carriers despite the similar cognitive performance, whereas inter-trial phase clustering was comparable in both groups.Preserved inter-trial phase clustering possibly compensates for the impaired power by eliciting the appropriate functional configuration needed for stimulus processing and task performance.

Background: Glucocerebrosidase (GBA) gene mutations and APOE polymorphisms are common in dementia with Lewy bodies (DLB), however their clinical impact is only partially elucidated. Objective: To explore the clinical impact of mutations in the GBA gene and APOE polymorphisms separately and in combination, in a cohort of Ashkenazi Jewish (AJ) patients with DLB. Methods: One hundred consecutively recruited AJ patients with clinically diagnosed DLB underwent genotyping for GBA mutations and APOE polymorphisms, and performed cognitive and motor clinical assessments. Results: Thirty-two (32%) patients with DLB were carriers of GBA mutations and 33 (33%) carried an APOE ɛ4 allele. GBA mutation carriers had a younger age of onset (mean [SD] age, 67.2 years [8.9] versus 71.97 [5.91]; p = 0.03), poorer cognition as assessed by the Mini-Mental State Examination (21.41 [6.9] versus 23.97 [5.18]; p

BackgroundIn major depressive disorder (MDD), patients often express subjective sleep complaints while polysomnographic studies report only subtle alterations in neural oscillations. We hypothesize that the study of aperiodic electroencephalographic (EEG) dynamics, a marker of excitation-to-inhibition balance, may bring new insights into our understanding of sleep abnormalities in MDD. Specifically, we investigate aperiodic neural activity during sleep and its relationships with the time of sleep, depression severity, and responsivity to antidepressant treatment.MethodsPolysomnography was recorded in 38 MDD patients (in unmedicated and 7d medicated states) and 38 age-matched healthy controls (N1=76). Aperiodic EEG activity was evaluated using the Irregularly Resampled Auto-Spectral Analysis with slopes’ means and intra-individual variability as outcome measures. Depression severity was assessed with the Hamilton Depression Rating Scale. We replicated the analysis using two independently collected datasets of medicated patients and controls (N2=60, N3=80).ResultsUnmedicated patients showed flatter aperiodic slopes compared to controls during N2 (p-value=0.002) and steeper slopes compared to their later medicated state (p-valuesConclusionFlatter slopes of aperiodic EEG power with increased variability may reflect unstable, noisy neural activity due to increased excitation-to-inhibition balance, representing a new disease-relevant feature of sleep in MDD.

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Objective Aside from the cognitive impairment, patients with dementia with Lewy bodies (DLB) have a high frequency of visual hallucinations and a number of other vision-related symptoms, whereas auditory hallucinations are less frequent. To better understand the differential dysfunction of the visual network in DLB, we compared auditory and visual event-related potentials and oscillations in patients with DLB. Methods Event-related potentials elicited by visual and auditory oddball tasks were recorded in 23 patients with DLB and 22 healthy controls and analyzed in time and time-frequency domain. Results DLB patients had decreased theta band activity related to both early sensory and later cognitive processing in the visual, but not in the auditory task. Patients had lower delta and higher alpha and beta bands power related to later cognitive processing in both auditory and visual tasks. Conclusions In DLB visual event-related oscillations are characterized by a decrease in theta and lack of inhibition in alpha bands. Significance Decreased theta and a lack of inhibition in alpha band power might be an oscillatory underpinning of some classical DLB symptoms such as fluctuations in attention and high-level visual disturbances and a potential marker of dysfunction of the visual system in DLB.

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) share pathological and clinical similarities while differing in the timing and severity of motor cognitive and visual impairment. Previous EEG studies found abnormal neural oscillations in PD, mild cognitive impairment (MCI) and Alzheimer's disease, however, the electrophysiological signature of clinical symptoms is still unclear. We assessed the specificity of event-related oscillations in distinguishing between cognitive, motor and visual involvement in patients with neurodegenerative conditions.EEG was recorded during a visual oddball task in 30 PD, 28 DLB, 30 MCI patients and 32 age-matched healthy controls. Target and non-target event-related power were examined in the time-frequency domain using complex Morlet wavelet convolution and compared within and between the study groups.MCI (z = - 1.8, p = 0.04, Cohen's d = - 0.5) and DLB (z = - 3.1, p 0.001, d = - 1.0) patients showed decreased delta-band target event-related synchronization compared to participants with normal cognition. PD (z = 1.6, p = 0.05, d = 0.5) and DLB (z = 2.7, p 0.01, d = 0.9) patients showed decreased beta suppression compared to MCI patients and controls. DLB patients with visual hallucinations (VH) showed decreased early-alpha suppression (z = 2.08, p = 0.019, d = 3.19, AUC = 1.0 ± 0.0) compared to DLB-VHDecreased event-related delta-band synchronization, reflecting a decline in information processing ability, was characteristic of cognitive impairment due to any cause. Decreased event-related beta suppression, reflecting impaired execution of motor action, was specific to PD and DLB. Decreased event-related early-alpha suppression was characteristic of the presence of VH in DLB. These findings show that specific oscillations may reflect specific clinical symptoms, being a marker of network dysfunction.

Introduction. In dementia with Lewy bodies (DLB), mutations in the GBA gene are associated with a more severe cognitive phenotype. In basic science, event-related oscillations have traditionally been used to explore the neurophysiological underpinnings of various aspects of cognitive performance. Here, we aimed to compare event-related oscillations in DLB patients who are carriers and non-carriers of GBA mutations.Method. EEG was recorded during a visual oddball task in eight clinically diagnosed Ashkenazi Jewish DLB patients with the N370S mutation in the GBA gene (GBA-DLB) and eleven DLB non-carriers. The time-frequency power and inter-trial phase coherence were calculated from the Morlet wavelet convolution from the Fz electrode.Results. Task performance and cognitive assessments were comparable between groups. While the within-non-GBA-DLB group analysis revealed a significant increase relative to the baseline in the delta-band power (p=0.01, Cohen's d=1.0), the within-GBA-DLB-group analysis did not detect any event-related power change. In contrast, both subgroups showed an increase relative to the baseline in the delta and theta bands inter-trial phase coherence (all p1.3). The between-group analysis revealed that event-related power - but not coherence - was lower in GBA-DLB compared to non-carriers in the delta band (p=0.04, d=-0.9).Conclusions. GBA-DLB patients showed decreased delta-band power compared to non-carriers despite the similar cognitive performance, whereas inter-trial phase coherence was comparable in both groups. These findings suggest that in carriers, preserved inter-trial phase coherence possibly compensates for the impaired power by eliciting the appropriate functional configuration needed for stimulus processing and task performance.

Objectives: In dementia with Lewy bodies (DLB) recurrent visual hallucinations (VH) often coexist or occur consecutively to impaired visual perception. Since in-depth neuropsychological testing is time-consuming, and therefore, not routinely performed in clinical settings, we aimed to explore whether standard cognitive screening tests may be helpful to alert a clinician to the presence of VH in DLB by exploring association between visuo-spatial dysfunction and VH. Method: The clock drawing, cube, and pentagons copying items from Montreal Cognitive Assessment and Mini-Mental State Exam and nonmotor Hooper visual organization test (HVOT) have been scored in DLB patients with and without VH using traditional and extended scoring methods. Results: Forty-five of 69 (65%) DLB patients were VH-positive (VH+). VH+ patients performed worse on the clock drawing (8.8/16 vs. 11.9/16, p = .016) with a higher rate of misrepresentation of time (69% vs. 29%, p = .002) and numbers (53% vs. 25%, p = .024). Likewise, VH+ patients performed worse on the HVOT (13.3/30 vs. 15.7/30, p = .009) having more isolated (6.2/30 vs. 4.4/30, p = .012) types of responses compared to VH- patients. Both groups had similar copying ability (p > .05). The VH discriminative accuracy of the clock drawing was comparable to that of the more elaborate test of visual perception, the HVOT. Conclusions: In DLB impaired drawing and visual organization, but not copying ability is associated with the presence of VH. The simple clock drawing test can be helpful to alert a clinician to the possibility of VH in DLB. (PsycInfo Database Record (c) 2021 APA, all rights reserved).