Pallesthesia

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As pallanaesthesia (from ancient Greek πάλλώ vibrate ' , swing') is referred to in the physiology of the senses , the sense of vibration . The term pallesthesia as a term for the sensory modality "vibration stimulus perception " was coined by Adam Rydel and Friedrich Wilhelm Seiffer in 1903, as well as the terms pallhypesthesia (reduced vibration stimulus perception) and pallanesthesia (lack of vibration stimulus perception). The perception of vibrations is a component of haptic perception , more precisely of fine perception ("epicritical sensitivity"). The functions of pallesthesia include a. differentiating between smooth and rough surfaces, safety when grasping and standing. Strong vibrations are perceived as unpleasant.

Basics

Vibration stimuli are received by special mechanoreceptors , the Vater-Pacini corpuscles . Specific stimuli are - according to Rydel and Seiffer 1903 - vibration frequencies between 32 and 256 Hz, the Vater-Pacini corpuscles respond less well to lower and higher frequencies.

The strength of the stimulus is defined by the vibration amplitude: if the vibration amplitude is low, it is weak, while large vibration amplitudes are correspondingly strong stimuli.

The perception threshold for vibration stimuli is defined as the stimulus strength (vibration amplitude) that is necessary to induce vibration perception. The perception threshold for vibration stimuli is age-dependent; it increases with age. This means that in old age - due to age-related decline in nerve performance (here the myelinated, fast-conducting Aß nerve fibers) - a certain pallhypesthesia occurs. In the case of certain diseases, the perception threshold is maximally increased, i.e. H. the greatest vibration amplitude does not generate any vibration perception (pall anesthesia).

Since the various body regions and structures (skeleton, joints, bones, skin) are covered with different densities of Vater-Pacini corpuscles, the pallesthesia is correspondingly different: the soles of the feet and the fingertips are the most sensitive.

Measurement of pallesthesia

The ability to perceive vibration stimuli can be measured semi-objectively using the method of quantitative sensory testing (QST). The decisive factor is the vibration stimulus perception threshold, which can be determined using various stimulation techniques:

  • Rydel and Seiffer vibration fork: The tuning fork, which is set in maximum vibrations, is placed with the end of its shaft on a bone structure; the swinging of the tines is translated into pushing movements of the handle. The oscillation amplitude, which decreases in the course of the oscillation process, can be determined semi-quantitatively on a scale from 0–8: 0–1 / 8 (= large amplitude, coarse vibration), to 7–8 / 8 (= smallest amplitude, finest vibration). Values ​​above 5 are considered normal perception thresholds.
  • Electric vibrators ( pallesthesiometers ), e.g. B. the biothesiometer (Biomedical Instruments, Newbury / Ohio USA) and the neurothesiometer (Horwell Scientific Laboratory Supplies, Nottingham UK) with a vibration frequency of 50 to 60 Hz and a stimulation range of 1 volt (minimum) to 50 volts (maximum vibration amplitude), as well as the Somedic Vibrameter (Somedic, Sweden) with a vibration frequency of 100 Hz and vibration amplitudes of 0.5 µm (finest vibration) to 500 µm (coarsest vibration). The vibration amplitude of the devices is varied by the examiner up to the perception by the test person. Kramer et al. examined the vibration perception threshold at the inner ankle with the Somedic Vibrameter (normal value around 2 µm); Peters et al. examined the tip of the big toe with the biothesiometer (normal value around 10 V).

The Rydel-Seiffer tuning fork, which is provided with a scale from “0” to “8”, is often used in everyday clinical practice. The person examined indicates when they can no longer feel the vibration (perception threshold). At this moment a value is read on the tuning fork. Values ​​below "6" are considered pathological. Typical sites for testing the pallanaesthesia are prominent bony landmarks, such as the inner and outer ankle ( medial malleolus and lateral ) on the foot, the tibial tuberosity to the tibia, the iliac crest ( crista iliaca ), the breastbone ( sternum ), distal portion of the spoke ( Radius ) and the elbow joint . The result of the examination can be used if the information yields constant values ​​after repeated testing of the same localization and, moreover, the vibration perception is better in certain areas. In occupational medicine , pallesthesiometers are more likely to be used, as they measure more precisely than the tuning fork.

Disruptions

Pallhyp or pall anesthesia can occur when the central nervous system or nerve tracts that guide the vibrational sensory quality are damaged. A common cause are polyneuropathies , for example, as a result of long-standing diabetes ( diabetes mellitus , then) as diabetic polyneuropathy denotes may occur. Other possible causes are damage to the spinal cord (for example in the case of paraplegia , herniated disc ), the lemniscal system or the sensory cortex in the parietal lobe of the cerebrum (for example, from a stroke ). Certain work-related vibration exposures from machines that lead to tissue damage can also cause pallhypesthesia (occupational disease vibration damage).

literature

  • K. Poeck, W. Hacke: Neurology . 12th edition. Springer, 2006, ISBN 3-540-29997-1 , pp. 56 ff .

Individual evidence

  1. Adam Rydel, Wilhelm Seiffer: Investigations into the feeling of vibration or the so-called "bone sensitivity" (pallesthesia) . In: Archives for Psychiatry and Nervous Diseases . tape 37 , 1903, pp. 488-536 , doi : 10.1007 / BF02228367 ( semanticscholar.org [accessed May 27, 2020]).
  2. C. Liniger, A. Albeanu, D. Bloise, JP. Assal: The tuning fork revisited . In: Diabetic Medicine . tape 7 , 1990, pp. 859-864 (English).
  3. HH. Krämer, R. Rolke, M. Hecht, A. Bickel, F. Birklein: Follow-up of advanced diabetic neuropathy. Useful variables and possible pitfalls . In: Journal of Neurology . tape 252 , 2005, pp. 315-320 , doi : 10.1007 / s00415-005-0645-y (English).
  4. EJG. Peters, LA. Lavery: Effectiveness of the diabetic foot risk classification system of the International Working Group on the diabetic foot . In: Diabetes Care . tape 24 , no. 8 , 2001, p. 1442-1447 (English).
  5. S. Riedel, N. Buddhdev, B. Husemann, J. Kinne: Investigation of the fine motor skills of the fingers after a high-frequency vibration load . 54th Spring Society. f. Ergonomics, April 9-11, 2008, Munich.
  6. Anonymous: Leaflet on occupational disease No. 2103 of the Annex to the Occupational Diseases Ordinance (BKV). (PDF) Retrieved July 20, 2020 .