Low Inter-Rater Reliability and Reproducibility of Neck Reflex/“Adler-Langer” Points in Neural Therapy Diagnostics but Increased Pressure Pain Threshold after Therapy: Results of a Randomized Controlled Observer-Blind Trial

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Background: Neck reflex points or Adler-Langer points are commonly used in neural therapy to detect so-called interference fields. Chronic irritations or inflammations in the sinuses, teeth, tonsils, or ears are supposed to induce tension and tenderness of the soft tissues and short muscles in the upper cervical spine. The individual treatment strategy is based on the results of diagnostic Adler-Langer point palpation. This study investigated the inter- and intra-rater reliability and explored treatment effects. Methods: We performed a randomized controlled trial with 104 inpatients (80.8% female, 51.8 ± 12.74 years) of a German department for internal and integrative medicine. Patients were randomized to individual neural therapy according to the pathological findings (n = 48) or no treatment (n = 56). In each patient, three experienced raters (20–45 years of experience in neural therapy) and two novice raters (medical students) rated Adler-Langer points rigidity on a standardized rating scale (“strong,” “weak,” “none”). The patients independently evaluated the tenderness on palpation of the eight points using the same scale. Pressure pain thresholds were assessed at the eight Adler-Langer points. All patients were retested after 30 min. The five raters were blinded to treatment allocation and assessments of the other raters. Video recordings were obtained to assess the consistency of the areas tested by the different raters. Results: Agreement between patients and raters (Cohen’s kappa = 0.161–0.400) and inter-rater reliability were low (Fleiss kappa = 0.132–0.150). Moreover, the individual agreement (pre-post comparisons in untreated patients) was similarly low even in experienced raters (Cohen’s kappa = 0.099–0.173). Video documentation suggests that raters do not place their fingers in the correct segments (percentage of correct position: 42.0–60.6%). Pressure pain thresholds at five of the eight Adler-Langer points showed significant changes after treatment compared to none in the control group. Conclusion: Under this artificial experimental setting, this method of Adler-Langer point palpation has not proven to be a reliable diagnostic tool. But it could be shown that, as claimed by the method, the tenderness in five of eight Adler-Langer points decreased after neural therapy.