Martin Bystad

Gender Differences in Placebo Analgesia: Event-Related Potentials and Emotional Modulation

Objectives: To examine whether there are gender differences in event-related potential (ERP) responses to painful stimulation after administration of placebo medication; and to investigate whether placebo medication reduces anticipatory stress and if this reduction can explain the placebo analgesic response. Several experimental and clinical studies have shown that males report lower pain compared with females. There are, however, few reports of gender differences in placebo analgesia. Methods: All subjects (n = 33; 17 women) participated in both a natural history and a placebo condition. ERPs were evoked by heat pulses with a peak at 52°C. Results: The results showed that pain unpleasantness and the N2/P2 ERP components were reduced in the placebo condition compared with the natural history condition. Only men displayed placebo responses in pain report and in the P2 component. Anticipatory stress was reduced after placebo administration, and the reduction in anticipatory stress was significantly related to the placebo effect on pain. Regression analyses revealed that the interaction of gender by anticipatory stress was significantly related to the mean placebo response, with men responding with lower stress after placebo medication, and larger placebo responses. Conclusions: A placebo response on pain unpleasantness was observed in men only, and reduced stress after placebo administration was observed in males only. Thus, reduced stress may be a mechanism for placebo responses in pain. ERP = event-related potential; NRS = Numerical Rating Scale.

How can placebo effects best be applied in clinical practice? A narrative review

Placebo effects are documented in a number of clinical and experimental studies. It is possible to benefit from placebo effects in clinical practice by using them as effects additive to those of documented and effective treatments. The purpose of this paper is to discuss how doctors and other health workers may benefit from placebo effects within an ethical framework. A narrative review of the literature relating to placebo effects in clinical practice was performed. We searched PubMed and selected textbooks on placebo effects for articles and book chapters relating to placebo effects in clinical practice. By drawing on placebo effects, doctors may access patients’ self-healing potentials. In practice, doctors may best benefit from placebo effects by influencing the patient’s expectations through communication. An important principle is to give the patient information stating that a particular treatment is effective, as long as this is based on realistic optimism. A patient-centered style involving elements such as developing trust and respect, exploring the patient’s values, speaking positively about treatments, and providing reassurance and encouragement might aid in activating placebo effects. The total effect of a documented treatment will partly depend on how well the placebo effects have been activated. Thus, placebo effects can be understood as a form of supplemental treatment.

Can 8 months of daily tDCS application slow the cognitive decline in Alzheimer’s disease? A case study

ABSTRACT This case study presents a patient with early-onset Alzheimer`s disease, who applied transcranial direct current stimulation (tDCS) daily for 8 consecutive months. This was a much higher frequency than previous tDCS studies. Neuropsychological assessments were conducted before the first tDCS session, after 5 months and after 8 months. After 8 months, the patient’s immediate recall improved with 39%, whereas delayed recall improved 23%. Overall, the results revealed that patient’s cognitive functions were stabilized. There may be slight possibility that tDCS could slow the cognitive decline in Alzheimer`s disease. This should be investigated in clinical trials.

The relation of hippocampal subfield volumes to verbal episodic memory measured by the California Verbal Learning Test II in healthy adults

ABSTRACT Total hippocampal volume has previously been shown to correlate with performance on tests for verbal episodic memory. However, there are sparse evidence on how hippocampal subfield volumes are related to verbal episodic memory in healthy adults. The present study investigated the association between volumes of separate hippocampal subfields and verbal episodic memory performance in healthy volunteers. Forty‐seven participants (31 females) between 20–71 years age underwent testing with the California Verbal Learning Test II (CVLT II), and the Wechsler Abbreviated Scale of Intelligence (WASI) to obtain an estimate of cognitive functioning. T1‐weighted MR images were obtained after cognitive testing, and volumetric estimates adjusted for age and estimated total intracranial volume were calculated in the FreeSurfer 6.0 software suite for cerebral ‐and hippocampal structures. The sample performed within the statistical normal range on both CVLT II and WASI. Significant correlations adjusted for multiple testing were found between CVLT II subtests of total learning, free immediate recall and free delayed recall and volumes of the left Cornu Ammonis (CA) 1–4 subfields. There were no significant correlations between right hippocampal subfields and CVLT II performance, and no significant correlation between WASI results and hippocampal subfields. The present results suggest that better verbal episodic memory measured by the CVLT II is associated with relative larger volumes of specific left CA hippocampal subfields in healthy adults. Due to the small sample size and large age‐span of the participants, the present findings are preliminary and should be confirmed in larger samples. HIGHLIGHTSVerbal memory was positively associated with volume of hippocampal subfields.Only left hippocampal subfields volumes were related to verbal memory performance.In healthy adults, the right subfields of the hippocampus were larger compared to the left.