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Einleitung: Die Anwendung therapeutischer Kommunikation im medizinischen Kontext, also die Verwendung von Wachsuggestionen ohne formale Hypnoseinduktion, beruht auf der Annahme, dass Patienten in medizinischen Situationen durch Angst und Stress in eine natürliche Trance gehen und dabei Suggestionen stärker wirken. Der Zustand von Patienten und die Behandlungserfolge werden wesentlich durch Nocebo-Effekte und Negativsuggestionen beeinflusst. In einer Pilotstudie an gesunden Probanden hat sich die maximale Armmuskelkraft als objektiver Parameter für messbare Effekte von Suggestionen aus dem medizinischen Umfeld erwiesen (Zech et al. (2019) Nocebo Effects on Muscular Performance – An Experimental Study About Clinical Situations. Frontiers in Pharmacology 10 (219), S. 1-11.) In einer klinischen Studie sollten nun dieselben Suggestionen an Patienten getestet werden. Methodik: In dieser experimentellen Studie wurde an 45 Patienten zu zwei Zeitpunkten (T1 = mehrere Tage vor einer geplanten Operation, T2 = am Vorabend einer geplanten Operation) die Wirkung von Suggestionen aus dem medizinischen Kontext auf die maximale Muskelkraft bei Abduktion des Armes in einem standardisierten Ablauf mit einem Dynamometer (Force Gauche FM200) gemessen. Es wurden verbale, situative und visuelle Suggestionen aus wesentlichen klinischen Themen getestet: die Beruhigung des Patienten, die Symptomabfrage, die Erinnerung an negative Situationen, die Erwartung einer ungewissen Zukunft, die medizinische Aufklärung, der Transport im Krankenhaus, der Blick aus dem Patientenzimmer, die Narkoseeinleitung. Die Messergebnisse wurden als Relativwerte angegeben. Neben typischen Suggestionen aus dem medizinischen Alltag, die als negativ eingeschätzt waren, wurde jeweils eine alternative, positive bzw. neutrale Suggestion formuliert und getestet. Die Reihenfolge der Suggestionen wurde randomisiert, wobei auf eine negative Version A immer eine beliebige positive bzw. neutrale Version B folgte, um unerwünschte kumulative Effekte zu vermeiden. Die situative Angst des Patienten wurde mit dem State-Fragebogen des State-Trait-Angst-Inventars (STAI-S, 20 Testitems) zu beiden Testzeitpunkten erfasst. Die Suggestibilität der Patienten wurde postoperativ mithilfe einer verkürzten Version des Harvard Group Scale of Hypnotic Susceptibility (HGSHS-5) gemessen. Ergebnisse: Die Suggestionen zeigten signifikante Wirkungen auf die maximale Armmuskelkraft. Alle Versionen A verminderten die Kraft signifikant im Vergleich zum Ausgangswert, bei den Sätzen um 7,7 bis 17,2%, bei den Situationen um 12,9 bis 17,2% und bei den visuellen Suggestionen um 7,8 bis 12,3%. Die Versionen führten nur bei dem Thema Aufklärung zu einer geringen aber signifikanten Kraftminderung, bei der Situation „positive Vergangenheit“ und bei der visuellen Suggestion „Transport“ zu einer signifikanten Kraftsteigerung. Alle übrigen Versionen B führten zu keiner Veränderung gegenüber dem Ausgangswert. Für alle Themen ergab sich ein signifikanter Unterschied zwischen Version A und Version B. Die Ergebnisse bestätigten sich beim zweiten Messzeitpunkt. Dem Trend nach, aber nicht signifikant, waren die Ergebnisse am Vorabend der Operation noch deutlicher. Die Werte des HGSHS-5 waren nicht normalverteilt, sondern wiesen eine zusätzliche Häufung bei 0 Punkten auf. Frauen erreichten signifikant höhere Werte als Männer, während das Alter keinen Einfluss aufwies. Zehn Patienten wurden als hochsuggestibel, zwölf als niedrigsuggestibel bewertet. Der STAI-S war mit 42 Punkten zum Zeitpunkt T1 und 48 Punkten am Vorabend der Operation deutlich erhöht. Die Verteilung der Werte war nicht homogen, sondern alters- und geschlechtsabhängig. Jüngere Patienten zeigten nicht signifikant niedrigere Angstwerte zum Zeitpunkt T1 aber einen signifikant stärkeren Anstieg der Angst (∆STAI-S) bei näher rückendem Operationstermin. Frauen wiesen zum Zeitpunkt T2 signifikant höhere Angstwerte als Männer auf und einen signifikanten Anstieg mit der Zeit. In einer multivariaten Regressionsanalyse stellten sich die Suggestibilität und die Zunahme der Angst (∆STAI-S) als Einflussgrößen auf die Suggestionswirkung heraus. Der Vergleich mit der Pilotstudie an Probanden ergab, dass die Wirkung der Suggestionen bei Patienten signifikant stärker ausgeprägt war. Diskussion: Die Studie zeigt eine deutliche Sofortwirkung von Suggestionen aus dem klinischen Kontext auf die maximale Muskelkraft von Patienten. Eine muskuläre Kraftminderung ist klinisch als ausgesprochen ungünstig einzuschätzen, weil sie beispielsweise die Sturzgefahr erhöht und eine Mobilisierung erschwert. Andererseits kann sie auch eine „Schwächung“ des Patienten in anderen Funktionen (wie Wundheilung oder Immunabwehr, die schwerer oder nur verzögert gemessen werden können), aber auch in umfassenderem Sinn andeuten. Dem gegenüber konnten durch alternative Formulierungen die schwächenden Effekte und damit Nocebo-Effekte nahezu komplett verhindert werden. In der Subpopulation „junge Patientinnen“ zeigte sich der deutlichste Anstieg der situativen Angst. Da diese zudem einen signifikanter Einflussfaktor auf die Suggestionswirkung darstellt, ist besonders dieser Patientengruppe am Vorabend der Operation eine erhöhte Aufmerksamkeit zu schenken, um z.B. Mut zuzusprechen oder erneut Vertrauen zu vermitteln., Background: The application of hypnotic communication in a medical context, respectively the usage of awake suggestions without a formal hypnotic induction, assumes that patients in medical environment pass into a natural state of trance due to anxiousness, pain and stress. Patients in a hospital are exposed to a great number of negative suggestions that can trigger negative expectations and corresponding nocebo effects or may have direct effects on treatment and the healing process. In a recently released pilot study (Zech et al. (2019) Nocebo Effects on Muscular Performance – An Experimental Study About Clinical Situations. Frontiers in Pharmacology 10 (219), S. 1-11.), a correlation between positive and negative suggestions and maximum arm muscle strength could be proven in healthy volunteers. In this study, these suggestions were tested on patients with upcoming surgery. Methods: In this experimental study, 45 patients were tested by dynamometry to evaluate maximal muscular strength during arm abduction in a standardized procedure. The measurement was carried out at two points of time (T1 = at least three days before surgery, T2 = in the evening before surgery). Verbal and non-verbal suggestions from daily clinical practice were randomly tested, whereas any negative version A was followed by a different neutral or positive version B. Results were expressed in percentage of the baseline value. Situative anxiety was measured with the state scale of the State-Trait-Anxiety-Inventory (STAI-S, 20 test items) in a german version. The suggestibility of the patients was investigated using a shortened form of the Harvard Group Scale of Hypnotic Susceptibility. Results: The suggestions showed significant effects on maximum muscle strength. All versions A reduced the strength significantly compared to the baseline (sentences by 7.7 to 17.2%, situations by 12.9 to 17.2%, visual suggestion by 7.8 to 12.3%). The versions B led to a small but significant force reduction only on the subject of “enlightenment”, whereas in the situation "positive past" and in the visual suggestion "transport" they led to a significant increase in strength. All other versions B did not change from baseline. For all subjects, version A and version B differed significantly. The results were confirmed at the second measurement point. Trending but not significant, the results were even clearer on the evening before surgery. The values of the HGSHS-5 were not normally distributed but showed an additional accumulation at zero points. Suggestibility scores of women were significantly higher than men, while age had no effect. Ten patients were considered highly suggestive, and twelve patients were considered low-suggestive. The STAI-S elevated with 42 points at T1 and 48 points at T2. The distribution of the values was not homogeneous, but age- and gender-dependent. Younger patients did not show significantly lower anxiety scores at T1, but a significantly greater increase in anxiety (ΔSTAI) as the surgery approached. Anxiety scores of women were significantly higher than men at T2 and had a significant increase over time. In a multivariate regression analysis suggestibility and increase in anxiety (ΔSTAI) turned out as major determinants of suggestive effect. In comparison with the pilot study on subjects the suggestive effects showed more weakening on patients. Discussion: The study shows significant immediate effects of suggestions from the clinical context to the maximum muscle strength of patients. Reduction of strength is clinically assessed as extremely unfavorable, for example, because it increases the risk of falling and makes mobilization more difficult. On the other hand, it can also indicate a weakening of the patient in other functions (such as wound healing or immune defense, which can be measured with difficulty or only delayed) but also in a comprehensive sense. In contrast, the weakening effects and thus nocebo effects could be almost completely prevented by alternative wordings. The subpopulation “young female patients” showed the most significant increase in situational anxiety. Since this also represents a significant influencing factor on the suggestion effect, this patient group should be given increased attention, especially on the evening before surgery, e.g. to encourage or to convey confidence again.

Introduction: The medical environment is full of suggestions that affect patients and their healing. Most of them inadvertently are negative, thus evoking nocebo effects. Recently, we have reported on the effect of such verbal and non-verbal suggestions as well as alternative formulations on maximal muscular arm strength in healthy volunteers. In the present study, we tested the same suggestions in patients at two time points to evaluate nocebo effects in a clinical situation and the impact of the approaching surgery date. Methods: In 45 patients, maximal muscular strength during arm abduction was measured by dynamometry of the deltoid muscle group. One test was several days before and the second on the evening before surgery. Baseline values were compared to the performance after exposure to 18 verbal and non-verbal suggestions. The sequence of presumably negative and positive suggestions was randomized for each patient in order to avoid cumulation effects of immediate succession of two negatives. State anxiety was evaluated at both time points, and suggestibility was measured after surgery. Results: Strong and statistically significant weakening effects were observed with all presumed negative suggestions from daily clinical practice including words of encouragement (91.4% of baseline), evaluation of symptoms (89.0%), announcement of a medical intervention (82.8%), a negative memory (86.5%), expectation of an uncertain future (82.8%), and non-verbal signals (87.7–92.2%). In contrast, alternative formulations did not interfere with muscular performance in most cases. A more pronounced effect was observed in the test repeated closer to the date of surgery, accompanied by a 15% higher anxiety level. The increase in anxiety correlated slightly with stronger weakening effects of suggestions, as did suggestibility. Conclusions: Negative suggestions cause a decrease in arm muscle strength, i.e., a “weakening” of the patient. This effect is enhanced by an increase in anxiety as the time of treatment, like surgery, approaches. The reaction can be avoided by alternative formulations. These nocebo effects that are objectively measured and quantified by a decrease in arm muscle strength are more pronounced in patients, i.e., in a clinical situation, than in healthy volunteers.

This paper has been selected by the Editors of General Relativity and Gravitation for re-publication in the Golden Oldies series. It is one of the papers cited in N. D. Birrell and P. C. W. Davies’ book Quantum Fields in Curved Space (Cambridge University Press, Cambridge, 1982) on the generalization of the Dirac Equation to a curved spacetime and is notable as containing the first occurrence of the well-known formula $$g^{\mu \nu }\nabla _\mu \nabla _\nu +m^2+R/4$$ for the ‘square’ of the Dirac operator. The original is in German and in a poorly accessible journal: it is presented here in English. The paper is accompanied by an editorial note by B. S. Kay which clarifies the historical development of the topic, and by a brief biography written by M. A. H. MacCallum.

This paper presents the results of a combined experimental, numerical, and analytical study of the occurrence of different vortex breakdown types and helical instabilities in realistic swirling combustor flows with axial air injection through a centerbody. A parametric study of the isothermal flowfield inside the combustion chamber and in the mixing tube upstream of the combustor is carried out in a water-tunnel test facility. Selected configurations were further assessed under reacting conditions. Next, a large-eddy simulation was conducted and successfully validated with the experimental data. The isothermal and reacting results show a strong effect of the inflow parameters on the type of the vortex breakdown and the frequency, amplitude, and shape of the global mode. Linear local hydrodynamic stability analyses, carried out on the time-average measured and simulated velocity data, yield the absolutely unstable domain inside the flowfield. Axial injection is shown to impede a zone of absolute instabilit...

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