Inhoudsopgave jaargang 5 (2010) / nummer 1

Instrumentele conditionering van frontaalkwabactiviteit bij gezonde jongvolwassenen

Een dubbelblind placebogecontroleerd onderzoek naar eeg-neurofeedback

HESSEL JAN ENGELBREGT, GILLES KOK, RUUD VIS, DANIEL KEESER, JAN BEREND DEIJEN

Neurofeedbacktraining (nft) is een methode waarvan wordt gedacht dat het hersenactiviteit kan beïnvloeden. Over deze techniek die veelal door psychologen wordt gebruikt, zijn veel publicaties verschenen in wetenschappelijke tijdschriften. Toch heeft nft binnen de psychologische en neurowetenschappelijke gemeenschap een status die in het gunstigste geval marginaal kan worden genoemd. Mogelijk is dit het gevolg van methodologische beperkingen die alle gepubliceerde onderzoeken naar nft kenmerkt.

In dit artikel beschrijven we een dubbelblind, placebogecontroleerd onderzoeksdesign. Dit design hebben we getoetst op praktische haalbaarheid door middel van een studie bij een groep van 25 gezonde studenten. Hierbij kreeg een controlegroep (n = 12) een pseudo-nft. De experimentele groep (n = 10) kreeg nft ter verhoging van frontale beta-activiteit (12-18 Hz) en inhibitie van de frequentieband 35-45 Hz. Dit leidde niet tot een duidelijk verbeterd cognitief presteren, wel tot de verwachte veranderingen in hersenactiviteit tijdens de behandeling. Op basis van deze methodologische toets denken we dat onze aanpak een haalbare oplossing biedt voor de methodologische problemen uit het verleden. nft is daarmee een toetsbaar fenomeen, volgens huidige evidence-based maatstaven.

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This study investigates a method to predict medical outcome of cholinesterase inhibitors in patients with Alzheimer’s disease (AD) and vascular dementia (VaD). Van Gool predicts that patients with cholinergic deficit symptoms will benefit from treatment whereas patients without will experience side effects because of overstimulation of the cholinergic system. We predicted that AD and VaD patients with a longer RT experience fewer side effects than patients with a faster response and that VaD patients have a longer RT than AD patients. A number of 71 patients with AD or VaD diagnosis were included. A sustained attention task was administered, as well as the MMSE and a questionnaire about side effects. Results indicated that VaD patients with a longer RT reported fewer side effects. Furthermore, patients with VaD had a longer RT than patients with AD. MMSE was negatively correlated with RT in the VaD group. Thus, the performance on the attention task seems associated with suffering from side effects and thus tends to predict medical outcome in VaD, but not in AD. Perhaps this attention task was not sensitive enough to measure cholinergic deficit symptoms in AD patients. Furthermore, different doses of medication might confound the effect for the AD group.

De heer V. (V.) lijdt sinds zijn jeugd onder een specifieke fobie met paniekstoornis. De paniek start wanneer hij de grenzen van zijn woonplaats bereikt, onafhankelijk van het type vervoer waarmee hij reist. Ook speelt de bestemming geen rol in het ontstaan of de ernst van de paniekaanval. Tijdens een autorit die een paniekaanval uitlokte zijn EEG opnames gemaakt. bèta activiteit (van 13-30 Hz.) bleek over grote delen van de cortex toe te nemen tijdens de paniekaanval. Verder was sprake van relatief plotselinge afname van delta en theta activiteit (1-8 Hz) over vrijwel de gehele cortex tijdens de paniekaanval.

The aim of this study was to explore the potential of default mode network (DMN) functional connectivity for predicting the success of smoking cessation in patients with tobacco dependence in the context of a real-time function al MRI (RT-fMRI) neurofeedback (NF) supported therapy.Fifty-four tobacco-dependent patients underwent three RT-fMRI-NF sessions including resting-state functional connectivity (RSFC) runs over a period of 4 weeks during professionally assisted smoking cessation. Patients were randomized into two groups that performed either active NF of an addiction-related brain region or sham NF. After preprocessing, the RSFC baseline data were statistically evaluated using seed-based ROI (SBA) approaches taking into account the smoking status of patients after 3 months (abstinence/relapse).The results of the real study group showed a widespread functional connectivity in the relapse subgroup (n?=?10) exceeding the DMN template and mainly low correlations and anticorrelations in the within-seed analysis. In contrast, the connectivity pattern of the abstinence subgroup (n?=?8) primarily contained the core DMN in the seed-to-whole-brain analysis and a left lateralized correlation pattern in the within-seed analysis. Calculated Multi-Subject Dictionary Learning (MSDL) matrices showed anticorrelations between DMN regions and salience regions in the abstinence group. Concerning the sham group, results of the relapse subgroup (n?=?4) and the abstinence subgroup (n?=?6) showed similar trends only in the within-seed analysis.In the setting of a RT-fMRI-NF-assisted therapy, a widespread intrinsic DMN connectivity and a low negative coupling between the DMN and the salience network (SN) in patients with tobacco dependency during early withdrawal may be useful as an early indicator of later therapy nonresponse.

Identifying treatment options for patients with alcohol dependence is challenging. This study investigates the application of real-time functional MRI (rtfMRI) neurofeedback (NF) to foster resistance towards craving-related neural activation in alcohol dependence. We report a double-blind, placebo-controlled rtfMRI study with three NF sessions using alcohol-associated cues as an add-on therapy to the standard treatment. Fifty-two patients (45 male; 7 female) diagnosed with alcohol dependence were recruited in Munich, Germany. RtfMRI data were acquired in three sessions and clinical abstinence was evaluated 3 months after the last NF session. Before the NF training, BOLD responses and clinical data did not differ between groups, apart from anger and impulsiveness. During NF training, BOLD responses of the active group were decreased in medial frontal areas/caudate nucleus, and increased, e.g. in the cuneus/precuneus and occipital cortex. Within the active group, the down-regulation of neuronal responses was more pronounced in patients who remained abstinent for at least 3 months after the intervention compared to patients with a relapse. As BOLD responses were comparable between groups before the NF training, functional variations during NF cannot be attributed to preexisting distinctions. We could not demonstrate that rtfMRI as an add-on treatment in patients with alcohol dependence leads to clinically superior abstinence for the active NF group after 3 months. However, the study provides evidence for a targeted modulation of addiction-associated brain responses in alcohol dependence using rtfMRI.

Nowadays a popular technique to improve mood and cognition is auditory beat stimulation (ABS), which is thought to induce a frequency-following response of brainwaves. The main types of ABS are monaural beats (MB) and binaural beats (BB). BB involves the presentation of a specific frequency to one ear and another frequency to the other ear which may induce neural entrainment. A difference between the frequencies of 40 Hz is assumed to improve cognition. The present study examined the effect of 40 Hz binaural beats (BB) and monaural beats (MB) on attention and electroencephalography (EEG). A total of 25 first-year psychology students (11 males, 14 females) performed a Flanker task while EEG was recorded during the 5 min-presentation of pink noise (PN), MB and BB. With respect to attention, as measured by the Flanker task, the number of false responses in the BB condition was smaller than that in the PN condition while the number of false responses in the MB condition was larger as compared to the PN condition. As there was no association of BB with a consistent increase in absolute 40 or 45 Hz power compared to PN or MB, EEG recordings could not confirm the hypothesized neural entrainment in the brain. Overall, the current findings show that listening to 40 Hz BB improves attention but do not show the occurrence of neural entrainment. Future research is recommended to include a larger sample, to use a broader cognitive test battery and to present auditory beats with a longer duration.