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Patient-conducted anodal transcranial direct current stimulation of the motor cortex alleviates pain in trigeminal neuralgia.

Hagenacker T, Bude V, Naegel S, Holle D, Katsarava Z, Diener HC, Obermann M - J Headache Pain (2014)

Bottom Line: The attack frequency reduction was not significant.No severe adverse events were reported.It may become a valuable treatment option for patients unresponsive to conventional treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, University Hospital Essen, Hufelandstr, 55, 45147 Essen, Germany. mark.obermann@uni-due.de.

ABSTRACT

Background: Transcranial direct current stimulation (tDCS) of the primary motor cortex has been shown to modulate pain and trigeminal nociceptive processing.

Methods: Ten patients with classical trigeminal neuralgia (TN) were stimulated daily for 20 minutes over two weeks using anodal (1 mA) or sham tDCS over the primary motor cortex (M1) in a randomized double-blind cross-over design. Primary outcome variable was pain intensity on a verbal rating scale (VRS 0-10). VRS and attack frequency were assessed for one month before, during and after tDCS. The impact on trigeminal pain processing was assessed with pain-related evoked potentials (PREP) and the nociceptive blink reflex (nBR) following electrical stimulation on both sides of the forehead before and after tDCS.

Results: Anodal tDCS reduced pain intensity significantly after two weeks of treatment. The attack frequency reduction was not significant. PREP showed an increased N2 latency and decreased peak-to-peak amplitude after anodal tDCS. No severe adverse events were reported.

Conclusion: Anodal tDCS over two weeks ameliorates intensity of pain in TN. It may become a valuable treatment option for patients unresponsive to conventional treatment.

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Related in: MedlinePlus

Fitting and configuration of the stimulation electrodes during transcranial direct current stimulation using a pair of surface rubber electrodes in a NaCl-solution soaked synthetic sponge over the primary motor cortex (M1) and above the contralateral orbit.
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Figure 1: Fitting and configuration of the stimulation electrodes during transcranial direct current stimulation using a pair of surface rubber electrodes in a NaCl-solution soaked synthetic sponge over the primary motor cortex (M1) and above the contralateral orbit.

Mentions: TDCS was delivered by a battery-driven constant current stimulator (Neuronica, Torino, Italy) with a maximum output of 5 mA using a pair of surface rubber electrodes in a NaCl-solution soaked synthetic sponge with an extension of 4×4 cm over the primary motor cortex (M1) and 5×10 cm above the contralateral orbit. The use of non-metallic rubber electrodes avoids electrochemical polarization (Figure 1). The electrode for tDCS is large, so that the stimulation encompassed a broad area of the motor cortex (upper limb and face). Patients received either anodal or sham stimulation, starting with either one in a double blind randomized fashion and were aware of the study design including sham stimulation. First, the hand area over the contralateral hemisphere to pain was determined by a single pulse transcranial magnetic stimulation (TMS). For anodal stimulation, the active electrode was placed over the hand representation field of the motor cortex and the reference was placed above the contralateral eyebrow according to the international 10–20 system for EEG electrode placement. The sham stimulation was administered by fixing the electrodes at the same positions and switching on the current for less than five seconds at a current strength below 500 μA in order to cause a slightly itching or tingling sensation and simulate the real current stimulation. Patients were asked if they feel the tingling. Thus, the patients felt the initial current sensation, but received no current for the rest of the stimulation period. With this procedure, patients cannot distinguish between verum and sham stimulation. The current was applied for 20 minutes at an intensity of 1.0 mA, according to current safety recommendations[17]. The maximum current density was 62.5 μA/cm2 over M1 and 12 μA/cm2 at the reference electrode. After the first stimulation, participants and at least one relative were instructed for the correct application of tDCS and were able to stimulate at home. Subsequently the patients applied the stimulation daily by themselves and were instructed to record daily, whether or not any potential side effects occurred in their diary. To ensure the correct application of tDCS, the stimulator records the correct current application in an electronic protocol. In cases of malfunctions or handling problems, the patients had the possibility to call the study team, which has not been used. Stimulation was performed for 14 days, 20 minutes per day. Following a cross-over study design participants were administered sham stimulation or anodal stimulation in a randomized order with an interval of at least one month after the first stimulation to avoid carry over effects.


Patient-conducted anodal transcranial direct current stimulation of the motor cortex alleviates pain in trigeminal neuralgia.

Hagenacker T, Bude V, Naegel S, Holle D, Katsarava Z, Diener HC, Obermann M - J Headache Pain (2014)

Fitting and configuration of the stimulation electrodes during transcranial direct current stimulation using a pair of surface rubber electrodes in a NaCl-solution soaked synthetic sponge over the primary motor cortex (M1) and above the contralateral orbit.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256974&req=5

Figure 1: Fitting and configuration of the stimulation electrodes during transcranial direct current stimulation using a pair of surface rubber electrodes in a NaCl-solution soaked synthetic sponge over the primary motor cortex (M1) and above the contralateral orbit.
Mentions: TDCS was delivered by a battery-driven constant current stimulator (Neuronica, Torino, Italy) with a maximum output of 5 mA using a pair of surface rubber electrodes in a NaCl-solution soaked synthetic sponge with an extension of 4×4 cm over the primary motor cortex (M1) and 5×10 cm above the contralateral orbit. The use of non-metallic rubber electrodes avoids electrochemical polarization (Figure 1). The electrode for tDCS is large, so that the stimulation encompassed a broad area of the motor cortex (upper limb and face). Patients received either anodal or sham stimulation, starting with either one in a double blind randomized fashion and were aware of the study design including sham stimulation. First, the hand area over the contralateral hemisphere to pain was determined by a single pulse transcranial magnetic stimulation (TMS). For anodal stimulation, the active electrode was placed over the hand representation field of the motor cortex and the reference was placed above the contralateral eyebrow according to the international 10–20 system for EEG electrode placement. The sham stimulation was administered by fixing the electrodes at the same positions and switching on the current for less than five seconds at a current strength below 500 μA in order to cause a slightly itching or tingling sensation and simulate the real current stimulation. Patients were asked if they feel the tingling. Thus, the patients felt the initial current sensation, but received no current for the rest of the stimulation period. With this procedure, patients cannot distinguish between verum and sham stimulation. The current was applied for 20 minutes at an intensity of 1.0 mA, according to current safety recommendations[17]. The maximum current density was 62.5 μA/cm2 over M1 and 12 μA/cm2 at the reference electrode. After the first stimulation, participants and at least one relative were instructed for the correct application of tDCS and were able to stimulate at home. Subsequently the patients applied the stimulation daily by themselves and were instructed to record daily, whether or not any potential side effects occurred in their diary. To ensure the correct application of tDCS, the stimulator records the correct current application in an electronic protocol. In cases of malfunctions or handling problems, the patients had the possibility to call the study team, which has not been used. Stimulation was performed for 14 days, 20 minutes per day. Following a cross-over study design participants were administered sham stimulation or anodal stimulation in a randomized order with an interval of at least one month after the first stimulation to avoid carry over effects.

Bottom Line: The attack frequency reduction was not significant.No severe adverse events were reported.It may become a valuable treatment option for patients unresponsive to conventional treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, University Hospital Essen, Hufelandstr, 55, 45147 Essen, Germany. mark.obermann@uni-due.de.

ABSTRACT

Background: Transcranial direct current stimulation (tDCS) of the primary motor cortex has been shown to modulate pain and trigeminal nociceptive processing.

Methods: Ten patients with classical trigeminal neuralgia (TN) were stimulated daily for 20 minutes over two weeks using anodal (1 mA) or sham tDCS over the primary motor cortex (M1) in a randomized double-blind cross-over design. Primary outcome variable was pain intensity on a verbal rating scale (VRS 0-10). VRS and attack frequency were assessed for one month before, during and after tDCS. The impact on trigeminal pain processing was assessed with pain-related evoked potentials (PREP) and the nociceptive blink reflex (nBR) following electrical stimulation on both sides of the forehead before and after tDCS.

Results: Anodal tDCS reduced pain intensity significantly after two weeks of treatment. The attack frequency reduction was not significant. PREP showed an increased N2 latency and decreased peak-to-peak amplitude after anodal tDCS. No severe adverse events were reported.

Conclusion: Anodal tDCS over two weeks ameliorates intensity of pain in TN. It may become a valuable treatment option for patients unresponsive to conventional treatment.

Show MeSH
Related in: MedlinePlus