Illustrationen zum übertragenen Schmerz

[Henry Head (1861-1940) and his importance for neurology]

Nowadays, Henry Head is best known for his Head zones. The concept was understood very differently by Head in comparison to what current medical books falsely describe them to be. In reality, there is no direct relationship between one particular skin zone and one single organ. It is certain that the drawings considered depictions of the Head zones in today's medical textbooks were actually not created by Head. From a neurological point of view, Head is important for two reasons: his self-experiment in 1909 to damage one of his own peripheral nerves followed by regeneration was heroic. It has helped generations of neurologists to have a better understanding of the pathophysiology of peripheral nerve damage and thus make a better assessment of the prognosis of such injuries. Head's second contribution pertains to the radicular organization at the level of the spinal cord. The pathophysiology of herpes zoster radiculitis enabled him to develop the concept of the dermatomes on the basis of preliminary work around 1900. Henry Head's contribution was the systematic compilation of the existing publications of the time and amendment of his own cases. As he was the most important neurologist at that time, at least in the English speaking world, and was well connected with people in the German neurology community, it was probably easy for him to make his dermatome maps well known. In retrospect, Head was less successful in neuropsychology with holistic concepts for higher cognitive functions which were in vogue during his lifetime. His late work on aphasia is now considered refuted. Head's criticism of the strict localization was well in syncronization with the zeitgeist of the early twentieth century. Establishing the fact that Broca's aphasia and Wernicke's aphasia are not easily diagnostically distinguishable from each other was more an achievement of subsequent generations of neurologists and neuropsychologists as well as technical advances.

Matrix stimulation in cancer pain: Methodology, safety and effectiveness

Background

This feasibility study addresses the applicability of matrix electrodes for the reduction of ongoing pain in cancer patients via low‐frequency electrical stimulation (LFS).

Methods

Low‐frequency matrix stimulation (4 Hz) was applied to the skin within the ‘Head's zones’ referring to the tumour localization of cancer pain patients. Pain at baseline was compared to a 3‐day treatment interval consisting of 5 min of matrix stimulation in the morning and evening followed by a 3‐day follow‐up period without therapy. Main outcome parameters included numeric rating scale values (rating scale 0–100), painDETECT, HADS, and German pain questionnaire, as well as the opioid intake, calculated as the oral morphine equivalent (OME).

Results

Twenty patients with cancer pain (aged 64.4 ± 10.3; 9 women) were examined. In the majority of patients, the pain was classified as nociceptive. The mean pain reduction achieved by matrix therapy was 30%, under stable daily controlled‐release opioid doses between 177 and 184 mg/day (OME). Seventeen patients (85%) were responders, defined by a pain reduction of at least 30%, while four responders experienced a pain reduction of over 50%. The only side effect was short‐term erythema.

Conclusion

Findings are consistent with the concept of synaptic long‐term depression in cancer pain induced after conditioning LFS. Despite the short, but well‐tolerated, treatment duration of 2 × 5 min/day, effects persisted throughout the 3‐day follow‐up.

Significance

Cutaneous neuromodulation using LFS via a matrix electrode has been shown to be a safe intervention for effectively reducing cancer pain in palliative care patients.

The gut-skin axis in health and disease: A paradigm with therapeutic implications

As crucial interface organs gut and skin have much in common. Therefore it is unsurprising that several gut pathologies have skin co-morbidities. Nevertheless, the reason for this remains ill explored, and neither mainstream gastroenterology nor dermatology research have systematically investigated the 'gut-skin axis'. Here, in reviewing the field, we propose several mechanistic levels on which gut and skin may interact under physiological and pathological circumstances. We focus on the gut microbiota, with its huge metabolic capacity, and the role of dietary components as potential principle actors along the gut-skin axis. We suggest that metabolites from either the diet or the microbiota are skin accessible. After defining open key questions around the nature of these metabolites, how they are sensed, and which cutaneous changes they can induce, we propose that understanding of these pathways will lead to novel therapeutic strategies based on targeting one organ to improve the health of the other.