Method and device to investigate or treat painful neuropathy

Abstract

A process and laser system for in vitro and in vivo pain research, pain clinical testing and pain management. In preferred embodiments of the present invention a diode laser operating at a 980 nm wavelength is used to produce warmth, tickling, itching, touch, burning, hot pain or pin-prick pain. The device and methods can be used for stimulation of a single nerve fiber, groups of nerve fibers, nerve fibers of single type only as well as more the one type of nerve fibers simultaneously. The device and the methods can be applied in a wide variety of situations involving the study and treatment of pain. Preferred embodiments of the present invention provide laser systems and techniques that permit mapping and selective activation of silent, C-mechano-insensitive fibers or A-delta or C-polymodal fibers, de-functionalization (depleting) of these fibers for the purpose of the treatment of peripheral neuropathy and monitoring of CGRP and substance P associated with stimulation of silent, C-mechano-insensitive fibers.

Claims

1. A process for stimulating nerves for conducting nerve research and investigations, said process comprising: A) generating pulses of infrared light with a diode laser system, B) controlling said laser to produce laser pulses of desired duration and power to produce a desired pulse power profile, C) directing at least a portion of said pulses of infrared light to a target comprising a single nerve or a portion of said single nerve so as to produce single mode stimulation of the nerve; wherein the diode laser system comprises: A) a diode laser producing laser pulses in a range of 100 ms to 10 sec B) a TV infrared camera adapted record images of a desired region of skin is used to record neurogenic flare, C) a thermal camera adapted to monitor a desired region of skin to control laser induce temperature and to record neurogenic flare, D) a cooling system adapted to cool a desired region of skin, and E) an LED adapted to illuminate desired regions of skin.

2. The process as in claim 1 wherein said infrared light is infrared light at wavelengths of about 980 nm.

3. The process as in claim 1 wherein said nerve fibers are C fiber nociceptors.

4. The process as in claim 3 and including a step of identifying the single type of stimulation as warmth stimulation.

5. The process as in claim 3 and including a step of identifying the single type of stimulation as single hot stimulation.

6. The process as in claim 3 wherein said nerve fibers are CMi fiber nociceptors

7. The process as in claim 1 wherein said nerve fibers are A-delta fiber nociceptors.

8. The process as in claim 7 and including a step of identifying the single type of stimulation as prick pin stimulation.

9. The process as in claim 1 wherein said controller comprises a personal computer.

10. The process as in claim 1 and further comprising a step for sensing temperature of said target.

11. The process as in claim 10 wherein said temperature sensor is configured to provide a temperature signal to said controller and said controller is programmed to utilize said temperature to provide feedback control of said laser in order to provide a desired temperature profile at said target.

12. The process as in claim 1 wherein said controller is programmed to provide laser pulsed according to a predetermined pulse energy profile to produce pain but no tissue injury.

13. The process of claim 1 and further comprising the steps of increasing of power for pulse duration 50-150 ms from power level of 0.5 W with step less than 0.2 W with a diameter of irradiation area 0.5-2 mm lead to produce clear monomodal (single) pin prick pain and selective activation of A delta fibers.

14. The process of claim 1 and further comprising the steps of increasing of pulse duration from 0.3 to 20 sec with power level around 1.5 W with a diameter of irradiation area 5 mm-15 mm lead to inducing of clear monomodal hot pain and selective activation of C nociceptors.

15. The process as in claim 1 and including a step of identifying the single type of nerve as a single nerve cell.

16. The process as in claim 1 wherein the said infrared light is directed to said target using an optical fiber with a core diameter chosen from a group of diameters consisting of: 20+/15 microns, 60+/15 microns and 100+/15 microns.

17. The process as in claim 1 wherein said infrared light is infrared light having a wavelength of about 1450 nm.

18. The process as in claim 1 wherein said infrared light is infrared light having a wavelength of about 1850 nm.

19. The process as in claim 1 wherein said infrared light is infrared light having a wavelength of about 810 nm.

20. A diode laser systems for investigating and treating painful neuropathy comprising: A) a diode laser producing laser pulse in a wavelength range of 800 nm to 1600 nm, B) a TV infrared camera adapted record images of a desired region of skin, C) a thermal camera adapted to monitor a desired region of skin, D) a cooling system adapted to cool a desired region of skin, and E) an LED adapted to illuminate desired regions of skin, F) a polarizer to illuminated unwonted reflected light from skin surface.

21. The diode laser system as in claim 20 wherein the wavelength is about 980 nm.

22. The process as in claim 1 wherein the diode laser single pulse is adapted to generate neurogenic flare below pain threshold.

23. The process as in claim 1 wherein the diode laser single pulse is adapted to generate neurogenic flare below pain threshold and if applied relatedly with interval over 200 sec may reproducibly activate neurogenic flare

24. The process as in claim 21 wherein repeatable application the diode laser single pulse with interval below 120 sec may deactivate, de-functianalize and temporary deplete CMi and other Heat sensitive pain mediated nerve fibers (nociceptors) and therefore provide pain relief for patients with peripheral pain.

25. The process as in claim 1 wherein the diode laser wherein the laser system is adapted to induce surface peak temperature in the range of of 45 C. to 60 C. at wavelengths of about 980 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 is a block diagram of a preferred embodiment of the present invention.

[0039] FIGS. 1A, 1B and 1C show various types of laser delivery systems.

[0040] FIGS. 2A and 2B show two additional types of delivery systems.

[0041] FIG. 3 shows a light delivery system with thermal imaging temperature feedback loop is similar to FIG.

[0042] FIG. 4 shows a two-dimensional scanner to map test locations and to provide treatment of affected painful areas on skin.

[0043] FIG. 5 shows two light delivery systems (two laser probes) to directly measure the speed of conduction of nerve fibers.

[0044] FIGS. 6A and 6B show a temperature pre-set single laser pulse and sequence of laser pulses similar that were used for stimulation of CMi fibers and neurogenic flare and nerve fiber de-functionalization (depletion) with and without skin cooling.

[0045] FIG. 7 A, shows kinetic of neurogenic flare in healthy subject in response to a laser pulse.

[0046] FIG. 7 B, shows kinetic of neurogenic flare in healthy subject in response to a laser pulse.

[0047] FIG. 7 C, shows kinetic of neurogenic flare in healthy subject in response to a laser pulse before and after CGRP treatment.

[0048] FIG. 8 shows the skin surface temperature during laser-induced de-functionalization (with cooling a) by cryogenic gas spray (liquid CO2).

[0049] FIG. 9 shows hand-piece schematic view of hand-piece with temperature control and video recording of neurogenic flare: a) without cooling b) and c) with spray and cuvette cooling.

[0050] FIG. 10 shows block diagram of hand piece connection to the controller, diode laser and liquid CO2 gas tank.

[0051] FIG. 11 is a table providing a description and some alternate names for some of the terms and acronyms used in this application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Diode Laser System at 980 nm

[0052] FIG. 1 is a prior art block diagram of a preferred embodiment of the invention described in U.S. Pat. No. 7,402,167. The present invention adds a collimator, a TV camera for recording of laser induced blood perfusion, a thermal camera to control laser induced temperature, an infrared LED for better contrast the blood perfusion, a skin cooling system and an LED.

[0053] FIGS. 1A, 1B and 1C are also prior art drawings from U.S. Pat. No. 7,402,167. The present invention also k provides a TV camera for recording of laser induced blood perfusion, a thermal camera to control laser induced temperature, a skin cooling system and an infrared LED for better contrast the blood perfusion.

[0054] FIGS. 2A and 2B show two additional prior art types of delivery systems from U.S. Pat. No. 7,402,167. The present invention replaces the prior art infrared camera with a TV camera for recording of laser induced blood perfusion, a thermal camera to control laser induced temperature, a skin cooling system and an infrared LED for better contrast the blood perfusion.

[0055] FIG. 3 shows the prior art light delivery system with thermal imaging temperature feedback loop from U.S. Pat. No. 7,402,167. The present invention adds the portable infrared thermal camera, TV camera with polarize filter for recording neurogenic flare (blood perfusion) connected to controller for real time processing, LED for irradiation skin for better contrast of neurogenic flare and skin cooling system based cool gas flow or cooled sapphire for additional skin protection during repeatable stimulation of CMi fibers.

[0056] FIG. 4 is also a prior art drawing showing a two-dimensional scanner to map test locations and to provide treatment of affected painful areas on skin from U.S. Pat. No. 7,402,167. As indicated above the present invention adds but with additional components: a TV camera for recording of laser induced blood perfusion, thermal camera to control laser induced temperature, skin cooling system and infrared LED for better contrast the blood perfusion

[0057] FIG. 5 again from shows U.S. Pat. No. 7,402,167 two light delivery systems (two laser probes) to directly measure the speed of conduction of nerve fibers but the present invention includes the additional components referred to above

[0058] FIGS. 6A and 6B show a temperature pre-set single laser pulse and sequence of laser pulses similar that were used for stimulation of CMi fibers and neurogenic flare and nerve fiber de-functionalization (depletion) with and without skin cooling.

[0059] FIG. 7 A, shows kinetic of neurogenic flare in healthy subject in response of laser pulse with peak temperature of 49 C. and duration of 1 s that was not evoked painful sensation. The laser light was applied to skin of inner forearm. Temperature was recorded by thermal camera, the reflected laser light by TV camera and blood perfusion by Speckle Imager (Perimed Corp, Sweden),

[0060] FIG. 7 B, shows kinetic of neurogenic flare in healthy subject in response of laser pulse with peak temperature of 49 C. and duration of 1 s that was not evoked painful sensation. The laser light was applied to skin of inner forearm. Temperature was recorded by thermal camera, the reflected laser light by TV camera and neurogenic flare was recorded by TV camera also

[0061] FIG. 7C, shows kinetic of neurogenic flare in healthy subject in response of laser pulse with peak temperature of 49 C. and duration of one second before and after application CGRP antibody.

[0062] FIG. 8 shows the skin surface temperature during laser-induced de-functionalization (depleting) with cooling a) by cryogenic gas spray (liquid CO.sub.2); The temperature feedback control peak temperature of stimulation below 50 C. and stop lasing if baseline temperature increased over 47 C. The cryogenic spray was used to provide additional safety. The 5 pulses of 500 ms with inter-pulse interval of 3 s were sufficient to provide de-functionalization (depletion). The processed biopsies (PGP 9.5 biomarker) of the treated and non-treated areas confirmed 50% efficacy of nerve fiber depletion.

[0063] FIG. 9 shows a hand-piece schematic view of hand-piece with temperature control and video recording of neurogenic flare: a) without cooling and with spray and cuvette cooling.

[0064] The preferred laser system shown in FIG. 1 is similar to described in FIG. 1 in the U.S. Pat. No. 7,402,167 with additional components: TV camera available turnkey as Model LI-USB30-V034M and from Leopard Imaging Inc. with office located in 1130 Cadillac Court, Milpitas, Calif. 95035, linear polarizer available turnkey for range 600-800 nm from Thorlabs Inc with office located in 56 Sparta Avenue Newton, N.J. 07860, Thermal Vision Camera available turnkey as LI-M38-THERMAL from Leopard Imaging Inc. with office located in 1130 Cadillac Court, Milpitas, Calif. 95035, Infrared Light Emitting Diode available turnkey as Model LED780E from Thorlabs Inc with office located in 56 Sparta Avenue Newton, N.J. 07860.

[0065] The laser system includes personal laptop computer (or tablet or specialised microprocessor) 13 programmed to provide the following functions, besides the functions described in the U.S. Pat. No. 7,402,167: [0066] Laser pulse or serial number of pulses that induced pre-set skin temperature from 36 C to 60 C with pulse duration from 100 ms to 60 sec [0067] Processing in real time TV image of blood perfusion

Advantages of the Present Invention

[0068] Some of the uses and advantages that the present invention provides are listed below: [0069] Selective stimulation of mechano insensitive fibers in humans and animal [0070] Behavioral (pain threshold) and instrumental (neurogenic flare threshold) assessment of activation of CMi fibers in animal [0071] Psychophysical (activation and pain thresholds) and instrumental (neurogenic flare threshold) assessment of activation of CMi fibers in humans [0072] Recording of laser induced neurogenic flare [0073] Monitoring of efficacy of medication that control CGRP in humans and animals [0074] Monitoring of efficacy of peripheral painful neuropathy treatment in healthy subjects, patients and animals [0075] Save de-functionalization (depleting) of spontaneously active C fibers that produce pain in pain patients

[0076] These preferred embodiments are similar as described in the in the U.S. Pat. No. 7,402,167 with addition of models: Lass 10M, Lass M-10M and Lass 11, diode laser fiber type selective stimulators (DLss) from LasMed LLC, 137 Irene Ct., Mountain View, Calif. 94043. Also, the present invention includes additional components: the component infrared camera 14 in the prior art device is replaced by the following components shown in FIG. 9: [0077] 1) A TV infrared camera 36 and additionally supplied with polarizer that prevent to observe light scattered from skin surface and increase contrast of observation of changes of blood perfusion. The TV camera is connected to the computer through a controller. [0078] 2) A hermal camera 34 that increase an ability control of laser induced temperature and allows monitor profile of heated area compared to thermal sensor described in the U.S. Pat. No. 7,402,167. The Thermal camera provides measurement of max temperature for temperature feedback to pre-set up and control laser induced temperature. It is connected to computer through controller. [0079] 3) Cooling system based of application of cryogen spray cooling by CO.sub.2 gas. Preferably the spray device is as described in Majaron paper (Majaron B, Svaasand L O, Aguilar G, Nelson J S. Intermittent cryogen spray cooling for optimal heat extraction during dermatologic laser treatment or a cooled sapphire cuvette similar (as described in Altshuler paper (Altshuler G B, Zenzie H H, Erofeev A V, Smimov M Z, Anderson R R, Dierickx C. Contact cooling of the skin. Phys Med Biol. 1999 April; 44(4):1003-23. PubMed PMID: 10232811) could be used. [0080] 4) A 750 nm wavelength light emitting diode with separate power supply to achieve better contrast for blood perfusion recording LED connected to the highly stabilized power supply. [0081] The above components are integrated around collimator as shown on FIGS. 9 and 10.

[0082] FIGS. 6A and 6B show the type of laser pulse induced temperature profile that is available with the laser system first described above. FIG. 6A shows temperature vs. time for single pulse and FIG. 6B shows temperature vs time for sequence of 5 pulses. The purpose here is to safely heat the skin to a temperature sufficient for activation of CMi fibers below temperature that may cause skin damage either by peak pulse temperature or build up baseline temperature by thermal feedback described above. The single pulses approach is used for measurement of thresholds of neurogenic flare (activation of CMi fibers) and pulse sequences for nerve fiber de-functionalization (depletion).

[0083] FIG. 7A, shows dependence of blood perfusion (kinetic of neurogenic flare) on time after stimulation with non-painful laser pulse that evokes temperature below 50 C. and induces threshold neurogenic flare from forearm skin of healthy subject. Temperature is recorded by thermal camera and the reflected laser light by TV camera as it described above. Blood perfusion is recorded by Speckle Imager (Perimed Corp, Sweden) that is cold standard in the field for the calibration.

[0084] FIG. 7B, shows the recording the same process as shown on FIG. 7 A, but TV camera as described above is used to record the neurogenic flare associated redness as well as reflected laser light. The LED and polarizer are used for better contrast as described above. The purpose here is to demonstrate that system of measurement of the neurogenic flare is sufficiently sensitive for determination of threshold of the activation.

[0085] FIG. 7C, shows dependence of blood perfusion (kinetic of neurogenic flare) on time after stimulation with non-painful laser pulse that evokes temperature below 50 C. and induces threshold neurogenic flare from forearm skin of healthy subject before and after application CGRP antibody that suppress neurogenic flare. The purpose here is to demonstrate that system allows to monitor efficacy of a CORP treatment.

[0086] FIG. 8 shows the skin surface temperature during laser-induced de-functionalization (depleting) with cooling a) by cryogenic gas spray (liquid CO2); The temperature feedback control peak temperature of stimulation below 50 C. and stop lasing if baseline temperature increased over 47 C. The cryogenic spray was used to provide additional safety. The 5 pulses of 500 ms with inter-pulse interval of 3 s were sufficient to provide de-functionalization (depletion). The processed biopsies (PGP 9.5 biomarker) of the treated and non-treated areas confirmed 50% efficacy of nerve fiber depletion. The purpose here is to demonstrate that system may allow temperature safe and efficient to treatment.

[0087] FIG. 9 shows example of hand-piece: 37 is the body of hand-piece cylinder made from laser protective polycarbonate (OD 5+ in the spectral range 700 nm to 1000 nm) located on the skin of the subject. On the cap of hand piece are located: 31LED, 32flexible pipe for cryogenic gas connected to liquid CO2 trunk, spray, 33 fiber optic connected to 34 collimator, 35 thermal camera connected to power supply and controller, 36 TV camera with polarizer connected to power supply and controller. The internal diameter of hand piece is over 50 mm that provide sufficient area for observation of neurogenic flare. The purpose here is to demonstrate that all components of system for treatment and measurement could be integrated and functioning together to provide research treatment and monitor efficacy of a CGRP treatment.

Monitoring and Treatment Procedures

Example 1: Protocol of Selective Activation of C Mechano-Insensitive Fibers in Humans

[0088] To the best of Applicant's knowledge, there are not any prior art data in the literature relating to selective activation of CMi as well as activation of neurogenic flare without painful stimulation of CMH fibers. The best, simplest protocol, to assess CMi and activate neurogenic flare is the following: [0089] The best laser set up parameters for lasing of 980 [0090] Pulse duration: 500 ms to 2 s, [0091] Beam size: 2 mm to 5 mm [0092] Power: 2-20 W sufficient for laser induced temperature from 45 C. to 55 C. [0093] Density of Energy Range: up to 10 mJ/mm.sup.2

[0094] The example of practical realization of the combination of pulse duration, beam size and laser induced temperature for reproducible activation CMi as well as short lasting (less than 120 sec) activation of neurogenic flare is shown in Table 1:

TABLE-US-00001 TABLE 1 Example of Threshold of activation of CMi fibers Stimulation of CMi fibers. Irradiated Spot Diameter 5 mm, Hair Skin Peak Temperature, Pulse, ms POWER, W, C. 500 18 56 1000 9 51 2000 3.5 48

[0095] The experiment consisted of the following actions: [0096] 1) Collimated beam with a diameter of 5 mm, within a range of power of 3.0-10.0 W and a pulse duration of 1 sec is applied to investigated area of skin to determine the individual sensitivity of CMi fibers and to record neurogenic flare. The pulse power is increased from 3 W with step of 0.5 W until first non-painful sensation is evoked. The area of stimulation each time slightly changed to prevent build up of baseline temperature. [0097] 2) The found intensity that evoked first non painful stimulation re-applies and possible changes of skin color like a redness caused by neurogenic flare response to laser irradiation is observed and recoded by TV camera with or without of LED lighting is observed in surround area of laser irradiation area of about 30 mm30 mm. [0098] 3) In case of observed redness the laser intensity is decreased with step of 0.1 W until no visible redness is observed and such intensity will be define as threshold of activation of CMi fibers. [0099] 4) In case if the intensity that evoked first non painful stimulation will not induce neurogenic flare the laser intensity is increased with step of 0.1 W until the redness will be observed and such intensity will be define as threshold of activation of CMi fibers.

Example 2 Protocol of Selective Activation of C Mechano-Insensitive Fibers in Humans with Cooled Skin

[0100] The steps to define activation threshold of CMi in cooled to skin are similar to the described in the Example 1. The cooled skin mimic to some degree skin and pain sensitivity of patients with peripheral neuropathy who usually develop deficit of pain sensitivity due to decreasing density of pain mediated fibers mainly epidermal C polymodal. The surface cooling also numbs epidermal C polymodal fibers. The only difference is that approximately twice higher laser intensity is required to induce the same temperature that sufficient for activation of CMi fibers. Therefore in step #3 The pulse power is increased from 6 W compared to 3 W in non cooled skin.

Example 3 Protocol of Selective Activation of C Mechano-Insensitive Fibers in Pigs

[0101]

TABLE-US-00002 TABLE 2 Example of Pain and Activation Thresholds of CMi fibers Stimulation of CMi fibers. Irradiated Spot Diameter 5 mm, duration 6 sec, intensity 2 W Hair Skin, Pig Pain Latency Pulse Duration, s Power, W Response, s Neurogenic Flare 6 2 2.5 Yes, observed before animal reaction to the stimulation* 0.5 2 n/a No** 1.0 2 n/a No** 1.5 2 n/a Yes** 2.0 2 n/a Yes** Notes: *non-anesthetized; **anesthetized

[0102] The experiment consisted of the following actions: [0103] 1) Collimated beam with a diameter of 5 mm, within a range of power of 2 W and a pulse duration of 6 sec is applied to investigated area of skin of non-anesthetized pig to determine the latency that cause a pain response: withdrawal or muscle ripples. The application is stopped then pig response and defined latency of pain threshold is recorded by infrared camera through controller to laptop (see FIGS. 1 and 1 A). The minimum latency for giving power is defined as pain threshold. The stimulation is repeated at least 6 times and all found latency values are averaged. The area of stimulation each time slightly changed to prevent build up of baseline temperature. [0104] 2) The animal is anesthetized and intubated. The pulse power is fixed the same as it was used for pain stimulation. The pulse duration decreased to 0.5 s and increased from 0.5 s with step of 0.5 s until first redness caused by neurogenic flare response to laser irradiation is observed and recoded by TV camera with or without of LED lighting is observed in surround area of laser irradiation area of about 30 mm30 mm. The area of stimulation each time changed to prevent build up of baseline temperature and overlapping of neurogenic flare.

Example 2 Protocol of Selective Stimulation Single Warmth Sensation or/and Single Hot Pain, Activation of C Fibers

Warmth Sensation Stimulation

[0105] The best laser set up parameters for laser at 980 nm: [0106] Pulse duration: 300 ms to 20 s [0107] Beam size: 3-15 mm [0108] Power: 0.3-10 W [0109] 1) A collimated beam with diameter 5 mm, power 1 W and pulse duration 5 sec is applied to investigate area of skin to determine the individual sensitivity of C nociceptors. The lasing is stopped when patient or volunteer report feeling either warmth or hot (burning) pain. The duration of applied pulse is measured. The procedure is repeated 2-3 times and after which the obtained pulse duration is used for the investigation of other areas. Every next pulse is applied to new area of skin if pain or other sensation has not disappeared. [0110] 2) The expected pulse duration is between 300 ms and 5 sec. A 300 ms power is increased with step of 0.2 W until the appropriate sensation appears. If the sensation doesn't occurred, then pulses with a duration of 5 sec are applied with increasing of power. [0111] 3) The inter stimulation time is at least 20 sec or until the pain sensation has disappeared. [0112] 4) For measurement of the Wind Up Effect, the area of stimulation is changed for each successive pulse if pulses applied are separated 2-10 sec. [0113] 5) Spatial summation curve: Power density of threshold of warmth or pain vs. Size of irradiated spot. Measurement size of irradiated spot is adjusted to 5 mm, 10 mm and 15 mm and actions 1-2 are repeated for each size with the same selected pulse duration. [0114] 6) For measurement of temporal summation curve (Power of Pain Thresholds vs. Pulse Duration) the action 2) is repeated with successive pulses. Pulse power is increased in 0.2 W steps. Expected pulse durations 300 ms-20 sec. [0115] 7) The time interval between applied laser pulses has to be more than 3-20 sec to avoid an average heating of skin and skin irritation. Exception is Wind Up Effect where indication of state of skin is subjective rating of pain level and monitoring of surface skin temperature. [0116] 8) For determining of the number of pulses that evoked threshold of hot/burning pain in accumulation of heat the square waved pulses within a range of pulse duration of 10-300 ms and inter-stimulus delay of 0.1-3 sec are applied. The examples of repetitive pulse application for C delta stimulation are shown in FIG. 14. [0117] 9) In the case of chronic pain syndromes diagnostics, there are differences between normal skin sensitivity and tender areas for example for fibromyalgia syndrome, the actions 5 and 6 are repeated for normal and tender areas before and after treatment. [0118] 10) In the case of testing of topical anesthetics or an analgesic drug actions, temperature of surface skin of investigated area at which pain occurs is monitored and data before and after application of topical anesthesia or a analgesic drug is obtained. [0119] 11) The pain thresholds as well as tolerance level are individual but suggested actions permit avoidance of temporal skin irritation and skin damage because the pain threshold level for 980 nm is lower than skin damage level. [0120] 12) ElectrophysiologyRecording Evoked Cortical Potentials: the pulse duration in the range 300-400 ms (up to 2 sec) is selected. The power may be measured as in step 4. The power is adjusted individually in the level between pain threshold and tolerance level. Trigger pulses, synchronized with laser pulse are applied to electroencephalographic protocols. The jitter from pulse with duration of 300 ms-2 sec could not resolve the time delay between even pulses applied to hand and shoulder for a very tall subject. To solve this problem two optical fiber probes method (see FIG. 5) and signal pulse method (see FIGS. 6A,B and FIGS. 15 A, B) were applied, to measure the time delay between two identically stimulated areas. The time delay was measured by delay time between brief trigger pulses.

Example 3 Application of Protocol Example 2 for Healthy Volunteers

[0121] The best laser set up parameters for laser at 980 nm: [0122] Pulse duration: 300 ms to 20 s, [0123] Beam size: 3-15 mm [0124] Power: 1-10 W [0125] Density Energy Range 9-140 mJ/mm.sup.2

TABLE-US-00003 TABLE 2 Example of threshold Hot Pain and Warmth Stimulations Pulse Area Energy Power Type of duration, size, Energy, Density, Density, Sensation ms mm2 Power, W mJ mJ/mm2 W/mm2 Warmth 300 38.5 4.7 1410 36.6 0.122 Warmth 300 176.6 5.8 1740 9.8 0.033 Warmth 1300 12.7 1.1 1430 112.6 0.087 Hot Pain 300 38.5 5.8 1740 45.2 0.151 Hot Pain 1300 19.6 2 2600 132.7 0.102 And Warmth

Example 4 Group Testing of a Delta Fibers

[0126] The following is a description a typical test procedure utilizing the present invention with the application of protocol Example 1 for healthy volunteers and pain patients:

[0127] Step 1: Preparing volunteer for test. The volunteers were asked to respond to stimuli after each stimulus was applied, and describing the level and type of evoked sensation, location of sensation, how long the sensation lasts, whether the sensation was single (monomodal) or if more than one sensation were evoked by stimulation.

[0128] Step 2: The level of power of laser was adjusted to skin type of volunteer and irradiated spot was selected as close as possible to A-delta receptors.

[0129] Collimated beam with diameter 2 mm, within range of power 5.0-10.0 W and pulse duration 100 ms is applied to an investigated area of skin to determine the individual sensitivity and to map the location of A delta nociceptors. The power is increased with step 0.5 W until the first sensation is evoked. After that, the pulse power is fixed and the position of the irradiated spot is scanned (tuned) within an XY frame 5 mm5 mm to find the location of the nociceptor and pulse power is applied for each new location with spatial steps of around 0.5 mm for fingertips.

[0130] The inter-stimulus time was at least 20 sec. The first appeared sensation was rated by the volunteer as barely pricking pain without any other sensations of warmth or hot pain.

Step 3

[0131] After the location of receptors were determined, the summation curvePower of Pain Threshold vs. Pulse Duration were measured by the following procedure: [0132] 1) Collimated beam was adjusted to 1 mm, [0133] 2) Duration of pulse set up to 50 ms and pulse power was increased from 2 W until volunteer reported about first appeared sensation. [0134] 3) Afterwards, power was increased until volunteer reported that sensation became clearly painful, but decreasing of power of stimulus on 5-10% leads to the disappearance of pain. [0135] 4) Afterward, the power threshold was measured for 50 ms pulse duration was increased by step 50 ms and procedure measurement of threshold was repeated. The increment of power was 0.1 W.

Step 4

[0136] The healthy volunteer was tested with pulse durations from 50 ms to 300 ms and beam size of 1 mm. The volunteer reported what around 200-300 ms, he felt on the same level of power firstly warmth and after that pricking pain but for pulses within range 50-150 ms, only single (monomodal) pricking pain was discerned. The sensations were sharp and disappeared in a few seconds after stimulation. The next stimulus was applied not earlier than 20 sec or after the disappearance of painful sensation of previous stimulus.

Step 5

[0137] To measure the tolerance level of pain the level of the power was increased more than threshold level with increment of 0.1 W until volunteer reported that his tolerance level of pain had been reached. The procedure of Step 3 was repeated. The volunteer rated his tolerance level as 10 and his threshold level of pain as 1.

Step 6

[0138] The thresholds of pin prick pain of healthy volunteers were measured in 20 minutes after topical analgesic (capsaicin) was applied on skin. The Steps 2, 3 and 4 were repeated.

Step 7

[0139] To determine a difference in pain threshold and summation curve between healthy volunteer and chronic pain patient the Steps 14 were repeated with patient with chronic hypersensitivity. The result of measurement are shown in Table 3.

Step 8

[0140] The level of skin irritation was measured by repetition of stimulation until redness of skin appeared for skin of healthy volunteers for stimulus duration of 150-300 ms and was recalculated for pulse durations of 50 and 100 ms. The Power level evoking skin irritation is shown Table 3.

[0141] As it is shown in Table 3, there is enough room to measure dependence of analgesic action between skin damage power level and initial pain threshold of pin prick pain. The shape of summation curve as well as pain thresholds allow to to determine the hypersensitive area of skin of chronic pain patient and test of selective action (A delta vs C fiber) of analgesic as well as diagnosing of that type of fiber is responsible for conducting of pain of patients.

TABLE-US-00004 TABLE 3 Power of Power of Power of Pain Pain Pain Power of Pain Threshold of Thresholds Tolerance Power of Thresholds of Chronic Pulse of Healthy of Healthy Skin Healthy Volunteer Pain Patient with Duration, Volunteer, Volunteer, Irritation, (Capsaicin), Hypersensitivity, (ms) (W) (W) (W) (W) (W) 50 9.5 11.9 16.6 14.8 7 100 4.5 5.6 7.9 7.0 3.5 150 3.2 4 5.6 5 2.5 200 2.8 3.5 4.8 4.3 2.2 300 2.5 3.1 4.4 3.9 2.2

Example 5 Stimulation of C Fibers Comparison of Chronic Pain Patient to Healthy Volunteer

[0142] Subjects: A chronic pain patient with hypersensitivity and a healthy volunteer were tested. Both subjects gave informed consent and the experiments were approved by the local institutional review board. The hairy skin of left hand was used for both volunteers. In preparing the subjects testing, they were asked to respond orally immediately after they perceived any threshold sensation and/or to interrupt lasing pulse by pressing STOP button. They then described the level and type of evoked sensation, location of sensation, how long the sensation lasted, whether the sensation was single (monomodal) sensation or if there were more than one evoked sensations by a single stimulation. Afterwards, the threshold pulse was applied 3 times to different areas with interval of {tilde over ( )}3 min or after the previous sensation (pain) had disappeared. The appearance redness was an indication of skin irritation.

[0143] Step 1: To test duration of pulse that evoked threshold warmth sensation only, the output power was set to 1.5 W, beam size adjusted to 5 mm. The pulse was applied to the skin. When the volunteer reported warmth (pain) sensation the lasing was stopped. The measured threshold pulse durations accordingly were 1300 ms for hot pain for the healthy volunteer, 800 ms hot pain for the healthy volunteer affected topical capsaicin (capsaicin decreases the thresholds of warmth sensation and hot/burning pain) and 910 ms hot pain thresholds for the volunteer with the hypersensitivity. The pulse duration for tolerance for hot pain was 2000 ms. Other studies has shown that redness (skin irritation) only occurs when pulse is extended to 3000 ms.

[0144] The laser radiation was stopped by volunteer. The volunteer used the other hand to push the stop lasing button when he perceived the sensation. When this button was pushed the command stop lasing was activated, duration of applied pulse was measured and it was indicated on the screen of PC connected to the device by RS232 interface.

[0145] For the double-checking of reflex time of volunteer, a infrared CCD camera (Sony) instead infrared thermal camera (14) FIGS. 1A-1C was applied to monitor the irradiated skin and reflex time. This method allowed to measure the real reflex time without time of delay related of individual reaction of volunteers. For tested volunteers the pulsed durations accordingly were: 1270, 650, 770 ms. This method also permitted the monitoring of the size of irradiated spots directly by infra red lasing as opposed to use the aiming beam. However, there was not found any differences between the diameter aiming beam and the diameter acting infra red lasing beam of irradiated spot. Accuracy of beam size measurement was +/0.50 microns.

[0146] Step 2: To measure the speed conductivity of C fiber alternatively of two probe method power which evoked hot pain sensation for pulse a duration of 300 ms was determined. This pulse duration is short enough to use it for measurement of speed conductivity by electroencephalographic recording of cortical evoked potentials. The output power was set up 1 W, spot size 7 mm with an increment of power was selected 0.1 W. The volunteer was asked to report the threshold of pain, skin sensation tolerance.

Example 3. De-Functionalization (Depleting) of Small Diameter Fibers Including CMi Fibers

Laser Induced Heat Treatment

[0147] Heat may cause temporal de-functionalization (depleting) of pain sensing fibers in patients with neuropathic pain that may provide the similar pain relief as application of capsaicin does. Topical capsaicin and other naturally occurring pungent molecules have long been used as analgesics to treat a variety of chronic pain conditions. The analgesic effects of these compounds have been attributed to their ability to desensitize nociceptors into a lasting refractory state up to their temporal de-functionalization and depleting with refractory time up to 8-12 weeks. Development of nonirritant TRPV1 agonists, i.e. ligands that do not evoke action potentials that lead to pain but desensitize TRPV1, has been actively pursued as alternatives to TRPV1 antagonists for pain relief. The capsaicin treatment requires repeated applications other several weeks of small concentration cream (>1.0%) or one time one hour application of high 8% solution or patch. The disadvantage of capsaicin patch application is induced prolong over 48 hours inflammatory pain due 48 hours residual time of capsaicin in the skin.

[0148] Laser induced heat pulses with temperature about 50 C. duration of 500 ms with interval of 3 sec with sequences of 5 pulses (50 C.) similar as shown on FIG. 8 were applied to the cooled by cryogenic CO2 spray to about 23 C. thigh area of skin. In 20 hours after treatment part of irradiated area were biopsied with 3 mm punches together with non-treated control and send to lab for estimation of skin damage Simultaneously to the thigh skin of another subject was treated with FDA approved 8% capsaicin patch. None skin damage was observed. In 6 days after treatment the pain sensitivity was tested (as described above in Example 2 of current application). the response from laser treated area demonstrated 20% decrease of pain sensitivity but response from capsaicin was the same as from control area.

[0149] In 7 days after treatment additional biopsies from laser and capsaicin treated areas together with control were taken and blindly processed with PGP 9.5 biomarker to determine the integral fiber density of the A delta and C fibers in epidermis and dermis. It was found that in capsaicin biopsies the fiber density was about 10 to 20% below control and laser treatment provide 50% to 60% fiber depletion.

[0150] This example 3 shows that laser irradiation permits noninvasive deactivation of TRPV1 positive cell, with heat playing an important role. The mechanism of deactivation and depletion of fibers with laser is more effective and less painful compared to the treatment that provided by 8% capsaicin patch. This mechanism can permit the development of pain relief and local anesthesia techniques for human and animal application.

[0151] While the present invention has been described in terms of specific embodiments, persons skilled in the art will recognize that many modifications and additions could be made to the specific embodiments without departing from the basic principals of the invention. For example many different wavelengths could be utilised if they the absorption in skin is within the range of about 0.25 cm.sup.I to 10 cm.sup.1. Fiber optics with core diameters in the range of 5 to 100 microns are good for transmitting the laser pulses. Temperature pulse shapes such as the following are good shapes for many experiments: [0152] 1. Increasing temperature to set value with arise time of 10-50 ms from baseline skin temperature up to set up level (45 C-60 C) for single non invasive activation of CMi fibers and neurogenic flare [0153] 2. Decreasing of intensity of each next stimulation in a sequence of pulses that are applied for de-functionalization (depleting) to prevent thermal skin damage from single pulse stimulation and baseline temperature build up. [0154] 3. Control baseline skin temperature during application of sequence of laser pulses below thermal skin damage level by cooling and decreasing of intensity of stimulation.

[0155] Therefore, the scope of the invention should be determined by the appended claims and their legal equivalents.