Entity

Time filter

Source Type


Solis-Vivanco R.,Instituto Nacional Of Neurologia Y Neurocirugia Manuel Velasco Suarez Innnmvs | Rodriguez-Violante M.,Neurodegenerative Diseases Laboratory | Rodriguez-Agudelo Y.,Instituto Nacional Of Neurologia Y Neurocirugia Manuel Velasco Suarez Innnmvs | Schilmann A.,Instituto Nacional Of Salud Publica | And 2 more authors.
Clinical Neurophysiology | Year: 2015

Objective: The P3a is an event-related potential (ERP) associated with involuntary attention and dopaminergic function. As P3a is reduced at initial stages of Parkinson's disease (PD), our objective was to assess P3a as a possible marker of PD duration and severity. Methods: Fifty-five patients were analyzed, 28 of which were at Hoehn and Yahr severity stage 1; 14 at stage 2; and 13 at stage 3. Seventeen patients were free of antiparkinsonian medication. PD duration was defined as the number of years between the onset of motor symptoms and the date of this study. Twenty-four healthy subjects were included as controls. An involuntary attention paradigm was administered while a digital EEG was obtained. Results: The P3a amplitude was significantly lower in all PD groups compared to the control group (F(3,75)=5.10, p=0.003), especially for stages 2 (p=0.017) and 3 (p=0.008). A regression analysis showed that the disease duration predicted inversely the P3a (Fz channel amplitude: Coefficient=-0.148, p=0.006; Frontocentral amplitude: Coefficient=-0.125, p=0.003) after controlling for demographic and clinical variables, medication, general cognitive state, and depression. Conclusions: This is the first study reporting P3a sensibility to PD duration and severity. Significance: This ERP could represent a reliable biomarker of the disease progression. © 2015 International Federation of Clinical Neurophysiology.


Solis-Vivanco R.,Instituto Nacional Of Neurologia Y Neurocirugia Manuel Velasco Suarez Innnmvs | Mondragon-Maya A.,Instituto Nacional Of Neurologia Y Neurocirugia Manuel Velasco Suarez Innnmvs | Leon-Ortiz P.,Laboratory of Experimental Psychiatry | Rodriguez-Agudelo Y.,Instituto Nacional Of Neurologia Y Neurocirugia Manuel Velasco Suarez Innnmvs | And 3 more authors.
Schizophrenia Research | Year: 2014

Mismatch Negativity (MMN), an electrophysiological component that represents sensory memory processing, has been proposed as a potential vulnerability marker for psychosis. Some studies have reported a more evident MMN amplitude reduction in the left cortical regions in patients with schizophrenia. Little is known about this asymmetric pattern in patients in their first episode of psychosis (FEP) and individuals at ultra-high risk for psychosis (UHR). The aim of this study was to explore the scalp distribution of MMN in 20 FEP patients, 20 UHR subjects and 23 healthy controls. Both clinical groups were antipsychotic naïve. MMN was obtained during a passive auditory paradigm with duration deviant tones and analyzed from 15 frontocentral electrodes. There was a significant group effect in MMN amplitude (F. = 3.4, p. = 0.04), showing a decrement in both FEP and UHR compared to controls (FEP mean difference (MD). = 0.48, p. = 0.02; UHR MD. =0.44, p. =. 0.04), and this amplitude decrement was more evident in the left middle regions for both clinical groups (p. <. 0.01). In conclusion, we found a clear amplitude reduction of duration MMN in FEP patients and UHR individuals, especially in the left cortical regions. The observed pattern in both clinical samples supports the notion that MMN could be a vulnerability marker for psychosis. We propose to continue the study of this MMN laterality effect in future longitudinal studies. © 2014 Elsevier B.V.

Discover hidden collaborations