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K² Stimulating Electrode
Concentric electrode for cutaneous stimulation of nociceptive fibers
In the pathophysiology of headache, the trigeminal nociceptive system plays a pivotal role.
Only few non-invasive methods are available to investigate the trigeminal nociceptive system. As a surrogate for measurements of trigeminal transmission the blink reflex (BR) can be used, but the majority of trigeminal afferents involved in BR after standard stimulation are non-nociceptive A-ß fibers.
Investigation of the nociceptive system further is a valuable approach to identify small-fiber neuropathy as occuring in HIV associated sensory neuropathy, or in diabetes. Presently applied tools for the detection of small-fiber neuropathy like sympathetic skin response, quantitative sensory testing, quantitative sudomotor axon reflex, laser evoked potentials or histological assessment of intraepidermal nerve fiber density are indeed expensive, time consuming and/or invasive, while standard nerve conduction studies generally are insensitive to small-fiber neuropathy.
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The K² electrode is a concentric planar stimulating electrode providing a non-invasive method to elicit a ‘nociception specific’ blink reflex (nBR).
By virtue of its concentric geometry and small anode–cathode distance a high current density can be achieved at relatively low current intensities, which limits depolarization preferentially and sufficiently to nociceptive fibers in the superficial layer of the dermis without recruitment of deeper lying non-nociceptive fibers.
Concentric electrode K2 (A) and the conventional normal electrode (B).Electric Fields are intimated.
Registration of the nociceptive blink reflex (nBR) as well as of trigeminal and peripheral pain related potentials (PREP) following nociception specific stimulation using the K² electrode both reflect pain processing in a quantitative way and are highly sensitive to changes in nociception.
Advantages
- affordable and easy-to-perform stimulation method, useful in clinical routine
- non-invasive and less traumatic than other non-invasive stimulation methods like heat stimulation;
skin biopsies may be avoided - superior to standard nerve conduction testing (SNC) in detecting impairment of small fiber function and subclinical small fiber neuropathy
- reflects the progress of neuropathy in a quantitative way
Areas of use
- migraine, headache
- trigeminal neuralgia
- small-fiber neuropathy
Examle of pain-related evoked potential (PREP) and nociceptive blink reflex (nBR). Stimulation sites along the three branches of the trigeminal nerve (V1, V2, V3) on either side. Simultaneous recording of PREP at Cz and nBR infraorbitally.Order and delivery
The K² stimulating electrode currently is available for research
- without connector
(order number: ELC-PAIN-S-4) - with 1.5 mm touch-proof connector
(order number: ELC-PAIN-S) - with 4 mm touch-proof connector for Digitimer stimulators
(order number: ELC-PAIN-S-D)
A trigger generator providing selectable current intensities in variable repetition rates is under development.
References
- Overview: Impaired trigeminal nociceptive processing in patients with episodic and chronic trigeminal neuralgia
- M. Obermann, M-S Yoon, D. Ese, M. Maschke, H. Kaube, H-C Diener and Z. Katsarava
Impaired trigeminal nociceptive processing in patients with trigeminal neuralgia
Neurology 2007; 69: 835-841 - Mark Obermann, Zaza Katsarava, Stefan Esser, Claudia Sommer, Lan He, Laura Selter, Min-Suk Yoon, Holger Kaube, Hans-Christoph Diener, Matthias Maschke
Correlation of epidermal nerve fiber density with pain-related evoked potentials in HIV neuropathy
Pain 2007; 138: 79–86 - Zaza Katsarava, Özgür Yaldizli, Christina Voulkoudis, Hans-Christoph Diener, Helger Kaube, Matthias Maschke
Pain related potentials by electrical stimulation of skin for detection of small-fiber neuropathy in HIV
J Neurol 2006; 253: 1581–1584 - I Ayzenberg, M Obermann, P Nyhuis, M Gastpar, V Limmroth, HC Diener, H Kaube, Z Katsarava
Central sensitization of the trigeminal and somatic nociceptive systems in medication overuse headache mainly involves cerebral supraspinal structures
Cephalalgia 2006; 26: 1106–1114 - Z. Katsaravaa, J. Ellrichb, H.C. Dienerc, H. Kaube
Optimized stimulation and recording parameters of human ‘nociception specific’ blink reflex recordings
Clinical Neurophysiology 2002; 113: 12–1932 - H. Kaube, MD; Z. Katsarava, MD; S. Przywara, MD; J. Drepper, PhD; J. Ellrich, MD, PhD; H.-C. Diener, MD, PhD
Acute migraine headache – Possible sensitization of neurons in the spinal trigeminal nucleus?
Neurology 2002; 58:1234-1238 - Z. Katsarava, MD, G. Lehnerdt, MD, B. Duda, J. Ellrich, MD PhD, H.C. Diener, MD PhD, H. Kaube, MD
Sensitization of trigeminal nociception specific for migraine but not pain of sinusitis
Neurology 2002; 59: 1450-1453 - H. Kaube, Z. Katsarava, T. Käufer, H.-C. Diener, J. Ellrich
A new method to increase nociception specificity of the human blink reflex
Clinical Neurophysiology 2000; 111: 413–416