Ear acupuncture

This is a technique claimed by both Western and Eastern camps and probably belongs equally well in both. It is probably the best-known microsystem in acupuncture. It was first recognized as a reflex system by Paul Nogier in the 1950s. There are two distinct classifications of points, those according to Nogier, adapted by Bahr, and those according to traditional Chinese medicine (TCM).

The ancient Chinese recognized that some channels passed around or through the ear and described all the Yang meridians as having some connection but had not fully appreciated the reflexes involved. Nogier on the other hand spent many years studying the ear and slowly built up his concept of the ‘man in the ear’, in which he described a human fetus in an upside-down position with the head in the region of the earlobe and the limbs towards the top of the ear (Figure 12.1).

Figure 12.1 • ‘The man in the ear’ according to Nogier.

(From Hopwood V. Acupuncture in Physiotherapy. Oxford: Butterworth-Heinemann, 2004, p. 142.)

Nogier’s ideas were imported into China in the mid-1950s and barefoot doctors were trained in auricular therapy techniques, using the map of points as illustrated, and enabled to treat a large range of problems.

Nogier postulated that if there is a change in the body system due to pathology then a corresponding change can be shown in the ear, on the appropriate region. In the case of pain the areas where pain is felt in the body have been shown to have a high correlation with tenderness in the points on the ear that correspond with the sites. Oleson et al. provided the statistical evidence for these defined regions with a 74% accuracy rate in defining the musculoskeletal pains of 40 patients [8]. This applies to many kinds of pathology, not just pain [9]. The area occupied on the ear surface is proportional to that in the cortex, so the upper limb, particularly the hand and face, seems well represented.

The standardization of nomenclature for ear acupuncture points has been slow: the two main schools, that of Nogier and the TCM point locations, have now been joined by the work of Frank and Soliman [10, 11] who built on the original Nogier extended work which described three basic phases – mesodermal, ectodermal and endodermal. The theory underlying this division is that the ear is composed of three different kinds of tissue in the developing embryo and each of these types is involved in differing somatotropic responses relating to the ear. Further, the different phases are associated with acute, intermediate and chronic pain conditions. An acupuncture atlas [12] just gives all the points with little or no explanation, leading to much confusion among students.

Auricular therapy is defined as a physical reflex therapy which detects somatic level disturbances on the auricle. There are precise zones of representation of organs, though these are not thought of as fixed points as they tend to have fluctuating boundaries, depending as they do on the metabolism of the organ. The right ear is said to represent the left hemisphere of the brain whereas the left ear represents the right hemisphere. Thus treatment will be on the same side as the problem.

The ear is associated with the parasympathetic nervous system, effectively modulating the sympathetic responses. The innervation of the central part of the ear links directly into the vagal nerve (the 10th cranial nerve). This means that rather than the ‘fight or flight’ response it tends to reduce the heart rate, lower blood pressure and facilitate digestion and excretion, thus returning the body processes to their normal rate. In short, in times of danger, the sympathetic system prepares the body for violent activity; the parasympathetic system reverses these changes when the danger is over.

Nogier discovered that there was a change in the amplitude of the human pulse as monitored at the wrist when tactile stimulation of the ear occurred. This was evidence of a sympathetic reflex affecting peripheral blood vessel activity. He referred to this as the auricular cardiac reflex. The changes detected are in waveform or amplitude, not in pulse rate. It is an involuntary arterial reflex and also known as the vascular autonomic signal, and is found as a vascular cutaneous reflex in response to other stimuli. This response to any form of tactile stimulus may explain the soothing effect of rubbing the ears, in both small children and dogs!

Acupuncture technique in the ear is slightly different to any other body surface. Short, fine needles are preferable and these are inserted carefully without piercing the cartilage of the ear. The reason for this care is that the cartilage has a poor blood supply so if it becomes infected it is difficult to eliminate the infection. This has led to recommendation of alcohol swabs to clean the surface before needle insertion.

Originally auriculotherapy was recommended for the treatment of nicotine or alcohol addiction and subdermal needles like tiny tacks were left in situ from one treatment to the next and covered by a small piece of plaster. This is discouraged nowadays because the risk of infection is too great.

The Chinese ear charts differ quite radically from those produced by Nogier, leading to considerable confusion among acupuncturists (Figure 12.2). There are many points on the TCM ear, located by way of a grid system and requiring a fine location skill. Chinese texts recommend the use of the points according to TCM principles, i.e. the Kidney point to treat bones, but since this appears to be a true reflex system this use is not supported scientifically.

Figure 12.2 • Chinese map of ear points

(from Hopwood V. Acupuncture in Physiotherapy. Oxford: Butterworth-Heinemann, 2004, p. 14.)

More important is the nerve supply to each part of the structure. The ear has an abundant innervation, being supplied by the sensory fibres of the trigeminal, facial and vagus nerves. The endings of these nerves are closely interwoven and can influence many distant body areas. Bourdiol gives an explanation based on embryology, emphasizing the fact that these nerves travel only a short distance to the reticular formation of the brainstem [13].

There are several ways of classifying the points. Oleson and Kroening [14] suggested nomenclature that depends on whether the points are located on raised, depressed or hidden areas in the ear. Otherwise the Chinese or Nogier maps are commonly used.

The mechanism appears to be the same as in the rest of the body. Ear acupuncture has been shown to affect the endorphin concentration and to be reversible by naloxone [15]. The study by Simmons and Oleson investigated changes in dental pain threshold after electroacupuncture stimulation to the ear, showing that true electroacupuncture produced a significant rise in the pain threshold while the placebo, using inappropriate ear points, did not.

All areas of the ear surface are utilized, with some points being located on raised areas, some in the depressions and some in hidden areas under folds of tissue and still others on the posterior surface of the ear.

When the two maps, that of Nogier and the TCM map, are compared it can be seen that some regions are similar but there are many single points that do not seem to tally. In physiotherapy practice the most commonly used auricular point is Shenmen, common to both, a sedative point located in the navicular fossa. As might be deduced from the name, this has similar applications to Heart 7 Shenmen, being used to calm anxious patients, often before further acupuncture is undertaken. The musculoskeletal zones are also frequently used, perhaps because they are easily located.

These points are used in conjunction with body acupuncture in many protocols for musculoskeletal acupuncture. They offer an alternative when points are inaccessible, either because of medical problems or plaster, or simply because of the difficulty of positioning or undressing the patient.

Points derived from the Chinese system of ear acupuncture are regularly used in drug addiction withdrawal programmes. The National Acupuncture Detoxification Association protocol uses five points – Shenmen, Liver, Lung, Sympathetic and Kidney – and is supported by some research [16]. This combination of points can produce profound relaxation in distressed patients so it has an application beyond that of drug withdrawal. It may owe more to the fact that the pinna is richly innervated and offers a good site to stimulate the central nervous system in a general way, but it has been utilized successfully in palliative care patients with serious anxiety states.