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M.V.Pronina 1 , Y.Y. Polyakov 1 , V.A. Ponomarev 1 , A.Müller 2 , J.D. Kropotov 1,3

Special features of independent components for ERPs from schizophrenics and SPD patients. M.V.Pronina 1 , Y.Y. Polyakov 1 , V.A. Ponomarev 1 , A.Müller 2 , J.D. Kropotov 1,3. 1 N.P. Bechtreva Institute of the Human Brain, RAS, (Saint-Petersburg, Russia)

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M.V.Pronina 1 , Y.Y. Polyakov 1 , V.A. Ponomarev 1 , A.Müller 2 , J.D. Kropotov 1,3

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  1. Special features of independent components for ERPs from schizophrenics and SPD patients M.V.Pronina1, Y.Y. Polyakov1, V.A. Ponomarev1, A.Müller2,J.D. Kropotov1,3 1 N.P. Bechtreva Institute of the Human Brain, RAS, (Saint-Petersburg, Russia) 2 Praxis für Kinder: Schul und Erziehungsberatung (Chur, Switzerland), CEO Brain and Trauma Foundation (Switzerland) 3The Norwegian University of Science and Technology (NTNU), (Trondheim, Norway)

  2. Schizophrenia is a multisymptomal disorder that characterized by impairments in three brain systems: • Impairments in affective system, such as blunted emotions; • Impairments in the sensory systems, such as auditory hallucinations; • Impairments in the executive system, such as paranoid or bizarre delusions or disorganized speech and thinking • (review Kropotov, 2008).

  3. VCPT test Probes: -Go (animal-animal) -NoGo (animal-plant) -Ignore (plant-plant) -Novel (plant-human) sound Participants were instructed to press the button as quickly as possible after Go probe (animal-animal) and donot press after other types of stimuli.

  4. EEG Registration 19-channel Electrocap with electrodes attached according to 10-20 system Electrodes resistance was less than 5 KOm. Digitizing sample rate was 250 Hz Amplifiers bandpass from 0,53 to 50 Hz Notch filter – 45-55Hz. Common average montage was used.

  5. Event-related potentials inGo/NoGo task Observed ERPs are generated in various cortical areas and have different temporal dynamics. Green line – Go condition, red line – NoGo condition.

  6. Independent components in Go/NoGo task • Go condition – thin line, NoGo condition – thick line. • The grand average ERPs are decomposed into 6 independent components which constitute 87% of the signal variance. • Components are generated in distinct cortical areas and reveal specific dependence on task conditions.

  7. Independent components of ERPs (sLORETA topographies) Probes Novel Probes NoGo left occipital-temporal auditory «Audit» «N170 L» right occipital-temporal «P3NOV C» «N170 R» Probes Go parietal premotor «P3GO P» «P3NOGO C» Probes NoGo anterior cingulate occipital «P3NOGO A» «NI VIS»

  8. The aim of our studywas to analize independent components of event-related potentials in active two-stimuli Go/NoGo test from schizophrenics and SPD patients and determine differences with healthy group.

  9. Subjects • 70schizophrenics in age from 18 to41years old. • Healthy group: 250participantsin age from 18 to 41 years old from HBI Database.

  10. Behavioral Data p<0,05

  11. Analysis of Independent components for ERPs Comparison 1: medicated and non-medicated patients Subjects: • 31medicated schizophrenics in age from 18 to41years old (mean age 29,5). • 39 patients free for any medicationin age from 19to 41 years (mean age 30).

  12. Analysis of Independent components for ERPs Comparison 1: medicated and non-medicated patients

  13. Analysis of Independent components for ERPs Comparison 2: patients with prevalence of positive and negative symptoms Subjects: • 26schizophrenics in age from 18 to41years old (mean age 29,5) with prevalence of positive symptoms. • 34 patients in age from 19to35years old (mean age 27) with prevalence of negative symptoms.

  14. Analysis of Independent components for ERPs Comparison 2: patients with prevalence of positive and negative symptoms *- p<0,05

  15. Analysis of Independent components for ERPs Comparison 3: patients with different forms of schizophrenia Subjects: • 17patients with paranoid schizophrenia in age from 18 to31years old (mean age 23,5). • 14 patients with simple schizophrenia in age from 19to31 years (mean age 25). • Joined group for 15 patients with catatonic and hebephrenic schizophrenia in age from 19to26years (mean age 22,5).

  16. Analysis of Independent components for ERPs Comparison 3: patients with different forms of schizophrenia *- p<0,05

  17. Analysis of Independent components for ERPs Comparison with norms Subjects: • 70schizophrenics in age from 18 to41years old. • Healthy group: 250participantsin age from 18 to 41 years old from HBI Database.

  18. Temporal components • Amplitude of the right N170 wave is redused in schizophrenics compare to healthy group. Size effect = 0,57 *- p<0,05

  19. Novelty reaction and parietal components Size effect = 1,01 Size effect = 1,11 *- p<0,05

  20. Frontal components Size effect = 1,21 Size effect = 0,50

  21. Symptoms of schizotypal personality disorder (SPD) 1) Ideas of reference (excluding delusions of reference) 2) Odd beliefs or magical thinking that influences behavior and is inconsistent with subcultural norms (e.g., superstitiousnessin children and adolescents, bizarre fantasies or preoccupations) 3) Unusual perceptual experiences, including bodily illusions 4) Odd thinking and speech (e.g., vague, circumstantial, metaphorical, overelaborate, or stereotyped) 5) Suspiciousness or paranoid ideation 6) Inappropriate or constricted affect 7) Behavior or appearance that is odd, eccentric, or peculiar 8) Lack of close friends or confidants other than first-degree relatives 9) Excessive social anxiety that does not diminish with familiarity and tends to be associated with paranoid fears rather than negative judgments about self

  22. Subjects • 9 SPD patients in age from 17to43years old. • 84 schizophrenics in age from 17 to 43 years old. • Healthy group: 311participantsof th same age range fromHBI Database. Behavioral Data red color - p<0,05

  23. Comparison of independent components of ERPs from SPD patients with norms - p<0,05

  24. Conclusions: • Schizophrenics make more omission mistakes compare to healthy subjects during the test execution and have significantly greater reaction time and standard deviation of reaction time.SPD patients did not differ from the database. • There are only three components which amplitude significantly differ inside the group of schizophrenics. • Peak values of right temporal component and novelty reaction, action engagement, action suppression and monitoring components are significantly decrased in schizophrenia compare to healthy people. That points on hypofunction of the frontal and parietal lobes. • In group of SPD patients only novelty reaction and action engagement components are diminished compare to the reference. These changes point on lower reactivity to extrnal stimuli and distortion of action engagemnt process. • Schizophrenia and SPD patients have different patterns of independent components changes which is in accordance with quality of test execution and severity of desease symptoms. Thus, Go/NoGo test and ICA-based method of analysis might provide a new approach for additional diagnostics of schizophrenia and schizotypal personality disorder.

  25. Thank you for your attention !

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