Cutaneous silent periods

Floeter, Mary Kay

doi:10.1002/mus.10447

Cited by 117 publications

(95 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Cutaneous SP is defined as a brief pause in the voluntary EMG activity that occurs in response to a painful stimulus applied to a cutaneous nerve. It is a spinal inhibitory reflex [7][8][9][10] with afferent impulses entering the spinal dorsal horn and suppressing activity in spinal motor nuclei. Afferent impulses that generate the cutaneous SP are carried primarily by smaller, slower conducting A-delta fibers.…”

Section: Discussionmentioning

confidence: 99%

“…This spinal inhibitory reflex designated as the cutaneous silent period (SP) is mediated primarily by small-diameter A-delta fibers, which enter the spinal dorsal horn and suppress activity in spinal motor nuclei in neighboring myotomes. [7][8][9][10] Cutaneous SP is altered in a variety of peripheral nervous system lesions. [11][12][13][14] Absence of radiculopathy, almost normal cutaneous SP has been observed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Preserved cutaneous silent period in cervical root avulsion

Vaško

Boček

Mencl

et al. 2015

The Journal of Spinal Cord Medicine

View full text Add to dashboard Cite

Objective: Brachial plexus injuries are usually severe and involve the entire brachial plexus, sometimes occurring with root avulsions. Imaging and electrodiagnostic studies are an essential part of the lesion evaluation; however, the results sometimes show a discrepancy. The cutaneous silent period (SP) is a spinal inhibitory reflex mediated by small-diameter A-delta nociceptive fibers. The aim of the study was to determine if cutaneous SP testing may serve as a useful aid in evaluation of brachial plexus injury and/or in the diagnosis of root avulsion. Methods: In 19 patients with traumatic brachial plexus injury (15 males, age 18-62 years) we performed a clinical examination, CT myelography and neurophysiological testing. A needle EMG was obtained from muscles supplied by C5-T1 myotomes. Cutaneous SP was recorded after painful stimuli were delivered to the thumb (C6 dermatome), middle (C7) and little (C8) fingers while subjects maintained voluntary contraction of intrinsic hand muscles. Results: Electrodiagnostic and imaging studies confirmed root avulsion (partial or total) maximally involving C5, C6 roots in 12 patients, whereas only in 4 of them the cutaneous SP was partially absent. In the remaining subjects, the cutaneous SP was preserved. Conclusion: In brachial plexopathy even with plurisegmental root avulsion, the cutaneous SP was mostly preserved. This method cannot be recommended as a reliable test for diagnosis of single root avulsion; however, it can provide a quick physiological confirmation of functional afferent A-delta fibers through damaged roots and/or trunks. The clinicians may add this test to the diagnosis of spinal cord dysfunction.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Preserved cutaneous silent period in cervical root avulsion

Vaško

Boček

Mencl

et al. 2015

The Journal of Spinal Cord Medicine

View full text Add to dashboard Cite

show abstract

“…18,26,27 ). Part of this discrepancy favors distinct spinal inhibitory circuitry mediated by low-and high-threshold afferents 13,18,[28][29][30] , with the possibility that dopaminergic influence is exerted only on low-threshold afferent circuitry. The latter may contribute to the electrically evoked CSP (ref.…”

Section: Discussionmentioning

confidence: 99%

Cutaneous silent periods in multiple system atrophy

̌Sťetkářová¹,

Kofler²,

Majerová³

2015

BIOMED PAP

View full text Add to dashboard Cite

Aim. The cutaneous silent period (CSP) is a spinal inhibitory reflex primarily mediated by A-delta fibers. Prolonged CSPs have been reported in patients with restless legs syndrome (RLS) and idiopathic Parkinson's disease (IPD). Dopaminergic medication normalizes the CSP, concurring with the effect of levodopa on CSPs. To date, CSPs have not been extensively studied in patients with multiple system atrophy (MSA). The purpose of this study was to confirm abnormal CSP findings in a group of MSA patients and to affirm the lack of influence of levodopa on CSPs during long-term treatment. Methods. We investigated 15 patients (4 males, 11 females, age 58-71 years) who fulfilled the diagnostic criteria for possible MSA. Thirteen patients had predominant parkinsonian symptoms (MSA-P), 2 had predominant cerebellar signs (MSA-C). We recorded CSPs in thenar muscles following noxious digit II stimulation. Sixteen healthy volunteers (6 males, 10 females, range 24-56 years) served as control subjects for CSP recordings. Results. Group average CSP onset was mildly delayed (P<0.01), whereas CSP end latency (P<0.001) were markedly delayed and CSP duration prolonged (P<0.001) in MSA patients compared to healthy controls. MSA patients on levodopa treatment did not differ in their CSPs from those without levodopa. The dose of levodopa did not correlate to any CSP parameter. Conclusion. The observed CSP prolongation corroborates previous findings in a limited number of MSA patients. The ineffectiveness of long-term levodopa on CSP abnormalities is consistent with its poor clinical effect in MSA.

show abstract

“…tary muscle activity on EMG, which is known as the silent period. 8,22 Most investigators agree that the afferent impulses that generate the silent periods are carried by the slow conducting ␦-fibers and that the latency of the response indicates an inhibitory spinal reflex. 24,41 Using H-reflexes, F-waves, and MEPs to assess motor neuron excitability, such studies have shown that motor neurons are inhibited throughout the time period that the CSP occurs-with maximal inhibition early in the CSP-with the given consensus that the motor neurons receive postsynaptic inhibition during the CSP and that the inhibition is transmitted through spinal inhibitory interneurons.…”

Section: 13mentioning

confidence: 99%

“…24,41 Using H-reflexes, F-waves, and MEPs to assess motor neuron excitability, such studies have shown that motor neurons are inhibited throughout the time period that the CSP occurs-with maximal inhibition early in the CSP-with the given consensus that the motor neurons receive postsynaptic inhibition during the CSP and that the inhibition is transmitted through spinal inhibitory interneurons. 8,14 It is strongly anticipated that silent period testing may reveal conduction abnormalities in these small sensory fibers missed by routine nerve conduction studies (SSEP and MEP monitoring), given that they reflect conduction via large myelinated fibers. The anatomical characteristics of thin myelinated pain-conducting fibers crossing the midline close to the central canal, where most of the syrinx cavities arise, suggest an early alteration of the silent period.…”

Section: 13mentioning

confidence: 99%

A new concept in the electrophysiological evaluation of syringomyelia

Röser¹,

Ebner²,

Liebsch³

et al. 2008

SPI

View full text Add to dashboard Cite

Object The current neurophysiological assessment of syringomyelia is inadequate. Early-stage syringomyelia is anatomically predisposed to affect decussating spinothalamic fibers that convey pain and sensation primarily. Silent periods have been proven to be a sensitive tool for detecting alterations in this pathway. Methods Thirty-seven patients with syringomyelia were included in this prospective study. Routine electrophysiological measurements were applied including somatosensory evoked potential (SSEP) and motor evoked potential (MEP) recordings for all extremities. The silent periods were recorded from the pollicis brevis muscle, and electrical stimuli were applied to the ipsilateral digiti II. To establish baseline values, the authors had 28 healthy controls undergo monitoring. Sensitivity and specificity values were statistically evaluated according to the main clinical symptoms (paresis, dissociative syndrome, and pain). Results All control individuals had normal silent periods in voluntarily activated muscle. In syringomyelia patients, the affected limb showed pathological silent periods with all symptoms (sensitivity 30–50%). Pain was the most specific symptom (90%), despite SSEP and MEP values that were within the normal range. Conclusions Silent period testing is a sensitive neurophysiological technique and an invaluable tool for preoperative assessment of syringomyelia. Silent periods are associated with early dysfunction of thin myelinated spinothalamic tract fibers, even when routine electrophysiological measurements still reveal normal values. Conduction abnormalities that selectively abolish the silent periods can distinguish between hydromyelia (a physiologically dilated central canal) and space-occupying syringomyelia.

show abstract

Cutaneous silent periods

Cited by 117 publications

References 67 publications

Preserved cutaneous silent period in cervical root avulsion

Preserved cutaneous silent period in cervical root avulsion

Cutaneous silent periods in multiple system atrophy

A new concept in the electrophysiological evaluation of syringomyelia

Contact Info

Product

Resources

About