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| ORIGINAL ARTICLE |
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| Year : 2014 | Volume
: 2
| Issue : 2 | Page : 126-130 |
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Effect of surface spinal stimulation on autonomic nervous system in the patients with spinal cord injury
Bhavkiran Kaur, Narkeesh Arumugam
Department of Physiotherapy, Punjabi University, Patiala, Punjab, India
| Date of Web Publication | 11-Nov-2014 |
Correspondence Address:
Narkeesh Arumugam
Department of Physiotherapy, Punjabi University, Patiala, Punjab
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2321-4848.144297
Background: The Autonomic Nervous System (ANS) plays a key role in the regulation of many physiological processes, mediated by supraspinal control from centers in the central nervous system. Spinal cord injury (SCI) decreases the ability to sympathetically control blood pressure and to regulate body temperature. Bladder dysfunction has been reported as a serious medical complication following SCI. The purpose of study is to find the effect of surface spinal stimulation on autonomic nervous system i.e., bladder function, skin resistance, and skin temperature. Materials and Methods: Five traumatic spinal cord injury subjects were selected for experimental pilot study; surface spinal stimulation for 45 minute period applied to the skin in T11-L2 area, with a carrier frequency of 2500Hz and modulated to beats frequency of 20Hz. Stimulation amplitude was raised to cause sensory stimulation. The pre- and post-stimulation values using the values of urodynamics testing, galvanic skin response, and infra-red thermometer compared in same patients and results were obtained. Results: Result of the present study indicates that four of five subjects demonstrate a decrease in the infused fluid volume, improved bladder sensation, but shown no effect over the bladder capacity. The skin resistance of the right lower limb was increased post-stimulation, but the improvement was not significant, and skin temperature of thigh and foreleg improved significantly. Conclusion: According to our results, surface spinal stimulation was effective to improve non-reflexive bladder, skin resistance and skin temperature, but further research is needed. Keywords: Autonomic nervous system, non-reflexive bladder, surface spinal cord stimulation, sites for stimulation, urodynamics
How to cite this article:
Kaur B, Arumugam N. Effect of surface spinal stimulation on autonomic nervous system in the patients with spinal cord injury
. Arch Med Health Sci 2014;2:126-30 |
How to cite this URL:
Kaur B, Arumugam N. Effect of surface spinal stimulation on autonomic nervous system in the patients with spinal cord injury
. Arch Med Health Sci [serial online] 2014 [cited 2023 Mar 23];2:126-30. Available from: https://www.amhsjournal.org/text.asp?2014/2/2/126/144297 |
| Introduction | |  |
The Autonomic Nervous System (ANS) plays a key role in the regulation of many physiologic processes, mediated by supraspinal control from centers in the central nervous system. Disruption of spinal cord decreases the ability to sympathetically control blood pressure and to regulate body temperature. Bladder dysfunction has been reported as a serious medical complication following spinal cord injury. The bladder and bowel functions are innervated by sacral cord segments, any complete lesion will result in fecal and urinary incontinence.
Normally, the bladder stores urine until the proper time for voiding and empties bladder in coordinated manner. An intact pathway between the pontine and sacral micturition centers allows for coordinated voiding by relaxation of the urethral sphincter and contraction of the detrusor muscle. Stimulation has been used to reduce hyperactivity of the bladder and to inhibit hyperreflexic contraction in the patients with spinal cord injury. Chronic electrical stimulation of perineal skin or sacral dermatomes proved to be effective for the management of stress urinary incontinence, urge continence and also shown favorable results of inhibited hyperreflexic contraction in urodynamic studies. [1]
Apart from the effect of spinal stimulation on bladder, little attention has been given to the other effects of spinal stimulation over the autonomic nervous system. It was reported that patients with peripheral vascular diseases experience sensation of warmth and alternations in blood flow in the skin after spinal stimulation. [2] These blood flow changes in the region of analgesia have been detected through thermography. Surface spinal stimulation is a form of electrical stimulation, which activates large diameter afferent fibers of paravertebral region, which may modulate the interneuronic activities of several spinal segments. [3] Previous studies, demonstrated that surface spinal stimulation may cause reflex vasodilation and helps to improve functioning of lower limb. The surface spinal sacral dermatome stimulation was found to be effective for the management of neurogenic bladder and detrusor instability. [4] The proposed study will describe the role of surface spinal stimulation on bladder function, skin resistance and skin temperature through comparing pre and post-stimulation values of urodynamics testing, galvanic skin response and Infra-red thermometer.
| Materials and Methods | | |
The present study is an experimental pilot study based on pre- and post- test regime, in which results were drawn after recording and analyzing the pre and post-stimulation values. For the present study, five traumatic spinal cord injury subjects were selected, out of which four were with complete and one was with incomplete injury through convenient sampling method. The subjects were included on basis of following criteria: Male subjects between the age of 25 and 50 years, traumatic spinal cord injury at middle thoracic and upper lumbar region, patient with bladder dysfunction of non-reflexive bladder, and patient able to understand or follow commands and instructions. Subjects were explained about the nature of study, and informed consent was taken from each and every patient.
The pre-stimulation skin temperature was recorded, in supine position with the help of hand-held IRL 300; Kusam-Medico thermometer, at the distance of 10-15 cm from the eight different sites of lower limb. The sites for skin temperature were right and left thigh from the anterior aspect (10 cm above the upper border of patella), posterior aspect (10 cm above the popilitus fossa), medial aspect (10 cm above from medial femoral epicondyle), lateral aspect (10 cm from the lateral femoral epicondyle), right and left foreleg from anterior aspect (5 cm below anterior lower border of popilitus fossa), and posterior aspect (5 cm below posterior lower border of popilitus fossa), right and left foot from planter aspect (heel of the foot), and dorsal aspect (10 cm from the tip of second metatarsal).
A cystometric test of urodynamic was performed to measure bladder capacity, bladder pressure, and bladder capacity when the urge to urinate begins. Once the bladder is emptied completely, the bladder is filled slowly with warm water. During this time, the person is asked to indicate when the need to urinate arises. To ensure bladder sensations patient was asked to cough and values of infused fluid volume, first sensation, first desire, normal desire and bladder capacity were recorded. The actual and basal galvanic skin responses were recorded using galvanic skin resistance meter; GBF-2000, MEDIC AID (GSR) via applying probes over the 2 nd and 4 th toe of right foot for 10 to 15 minutes.
Two adhesive rectangular electrodes of size (4.5 x 9 cm) were placed on each side of supine 5 cm apart over T10-L2 level paravertebrally and electrical stimulation has amplitude modulation alternating current with a carrier frequency of 2500 Hz, beat frequency 20 Hz was delivered to produce only sensory stimulation, continuously for 45 min. After the stimulation, post- stimulation values were recorded immediately in patients with SCI through urodynamic studies, GSR, and infrared thermometer. Statistical analysis was done by calculating mean and standard deviation values of all measured variables from the same sample. Treatment measures were compared using t-test for independent means. A difference between two means was considered to be statistically significant when P value was less than 0.05.
| Results | | |
The urodynamic values include pre- and post-stimulation values of infused fluid volume (IV), intravesical pressure (Pv), first sensation (FS), first desire (FD), normal desire (ND) and bladder capacity (BC). Mean and standard deviation of pre-stimulation values of IV were 270.60 ± 26.24, PV 59.80 ± 18.26, FS 186.60 ± 34.86, FD 224.20 ± 37.42, ND 236.20 ± 35.43, BC 272 ± 25.20 and post-stimulation values of IV were 268.80 ± 38.54, PV 69.00 ± 23.95, FS 202.60 ± 27.85, FD 218.80 ± 36.97, ND 247.00 ± 26.27, and BC 265.00 ± 34.73, respectively [Figure 1]. The values had shown no significant changes in post-stimulation cystometric measures. The improvements were observed in the values of skin resistance following stimulation, but were not statically significant. The mean and standard deviation of pre-stimulation AGSR was 131 ± 77.63 and post-stimulation values was 191.25 ± 91.63. The mean and standard deviation of pre-stimulation BGSR was 144.75 ± 78.69 and post-stimulation BGSR was 215.75 ± 94.54 [Figure 2]. The significant improvement in the thigh and foreleg values of skin temperature was observed; the values of skin temperature over the thigh and foreleg were significant [Table 1] and [Table 2] and [Figure 3], [Figure 4], [Figure 5], [Figure 6].  | Table 1: Presenting the t-values of skin temperature measured from thigh area
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 | Table 2 : Presenting the t-values of skin temperature from calf and foot area
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 | Figure 1: Presenting the comparison of mean value of cystometric variables at pre- intervals within the group
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 | Figure 3: Comparison of mean values of pre- and post- interval skin temperature of right thigh
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 | Figure 4: Comparison of mean values of pre- and post- interval skin temperature of left thigh
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 | Figure 5: Comparison of mean values of pre- and post- interval skin temperature of right calf
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 | Figure 6: Comparison of mean values of pre- and post- interval skin temperature of left calf
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[Table 1]: The t-values for right and left thigh anterior were −2.138 and −2.500, which were significant. The t-values of right and left thigh posterior were −2.138 and −2.138, which were also significant. The t-values of right and left thigh lateral were −2.500 and −2.138, which were significant. The t-values of right and left thigh medial were −2.138 and −2.138; which were also significant.
[Table 2]: The t-values of right and left calf anterior (RCA, LCA) both were −4.000 and −4.000, which were significant. The t-values right and left calf posterior (RCP, LCP) were −2.138 and-2.138, which were significant. The t-values of right and left foot dorsal aspect (RFD, LFD) were −1.177 and −1.633, which were not significant. The t-value of right and left foot posterior aspect (RFP, LFP), were −0.784 and −0.784, which were not significant to show statistical difference in the p-values. Hence, statistical values of foot area were not significant.
| Discussion | | |
The autonomic nervous system is a complex neural network that controls many elements of human physiology, organized into two divisions: The sympathetic (thoraco-lumbar) and the parasympathetic (craniosacral) system. The systems integrate functionally with each other to provide balanced regulation of innervated organs. Serious disturbances in autonomic nervous system function depend upon the degree, level and extend of the injury. [5] Autonomic nervous system helps to maintain homeostasis within the body; normal functioning of autonomic nervous system depends upon the integrity of the spinal cord. Loss of supraspinal control due to an interruption of descending autonomic tracts will lead to disturbance in the functioning of the cardiovascular, respiratory, and thermoregulatory systems, bladder and bowel control, sexual function. [6]
Limited experience exists for the use of surface spinal stimulation and its effect over autonomic nervous system in patients with SCI. The inhibition of first sensation occurs due to the depolarizing somatic sacral and lumbar afferent fibers. [4] Afferent stimulation provides central inhibition of pre-ganglionic bladder motor neurons reduced bladder sensations. The main findings are the values of urodynamics which showed that surface spinal stimulation with surface electrodes on the skin of thoraco-lumbar area improved bladder function in the patients with spinal cord injury. Improvements in bladder sensations were not statically significant. Two studies reported significant reduction of bladder sensations following electrical stimulation of tibial and pudendal nerve stimulation due to inhibitory effect of sacral afferent pathways in hyperreflexic bladder by depolarizing somatic sacral afferent fibers. [1],[4]
It was also reported that the low frequency stimulation of 5 Hz shows optimal inhibitory effect, and high frequency current of 50 Hz has been reported to achieve urethral closure. [7] Parasympathetic electrical stimulation may activate large diameter afferent fibers of paravertebral region, which may modulate the interneuronic activities of several spinal segments. The same method of electrical stimulation proposed to improve control of stretch reflex and to modulate the transmission of afferent or efferent impulses resulting from generalized desensitization of spinal pathways. [3] Brindley [8] reported that the smooth muscles of detrusor relax more slowly than the striated muscles of urethral sphincter, develop pressure gradient and cause micturition.
Both the skin resistance and skin temperature measurement are the sensitive methods to assess autonomic nervous system. The skin resistance values shown non-significant improvement in post-stimulation values. Ogura [9] reported that patients with spinal cord injuries had shown no response to electrical stimuli at either upper or lower limbs. While the results obtained from normal healthy subjects shown shortest latency from palm, then from sole, all the sympathetic skin responses was 1.2 to 1.4 ms. The sympathetic skin responses specifically test the skin sympathetic fibers, not parasympathetic fibers or motor sympathetic fibers that mediate clinical symptoms of dysautonomia. [10] Skin temperature over the thigh and foreleg was significantly improved following stimulation. The possible underlying mechanism of increase in skin temperature, below the interrupted autonomic dermatome level in SCI, was the presence of some local reflexes of vasoconstriction and dilation. [11]
| Conclusion | | |
The present study found that surface spinal stimulation with medium frequency current of beat frequency 20 Hz is effective to improve bladder sensations, infused fluid volume, and bladder capacity, but these changes were not up to the mark of significance. Electrical stimulation over the paravertebral region also depicted improvement in mean and standard deviation of skin resistance, but was only statistically significant. Surface spinal stimulation showed significant increase in post-stimulation values skin temperature over thigh and foreleg significantly, but no significant changes were observed in skin temperature of foot.
| References | | |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]
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