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Changes of medium-latency SEP-components following peripheral nerve lesion.

Stendel R, Jahnke U, Straschill M - J Brachial Plex Peripher Nerve Inj (2006)

Bottom Line: Surprisingly 16 of the 29 patients (55.2%) showed a reduction or elimination of N35, P45 and N60.With paired stimulation a suppression of the amplitude of N20, P25 and P45 (p < 0.05; sign test), and a marked increment of N35 (p < 0.05; sign test) and N60 (not significant; sign test) of the second response could be observed.The results of the present investigation do not provide evidence of collateral innervation of peripherally denervated cortical neurons by neurons of adjacent cortical representation areas.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany. ruediger.stendel@charite.de

ABSTRACT

Background: Animal studies have demonstrated complex cortical reorganization following peripheral nerve lesion. Central projection fields of intact nerves supplying skin areas which border denervated skin, extended into the deafferentiated cortical representation area. As a consequence of nerve lesions and subsequent reorganization an increase of the somatosensory evoked potentials (SEPs) was observed in cats when intact neighbouring nerves were stimulated. An increase of SEP-components of patients with nerve lesions may indicate a similar process of posttraumatic plastic cortical reorganization.

Methods: To test if a similar process of post-traumatic plastic cortical reorganization does occur in humans, the SEP of intact neighbouring hand nerves were recorded in 29 patients with hand nerve lesions. To hypothetically explain the observed changes of SEP-components, SEP recording following paired stimulation of the median nerve was performed in 12 healthy subjects.

Results: Surprisingly 16 of the 29 patients (55.2%) showed a reduction or elimination of N35, P45 and N60. Patients with lesions of two nerves showed more SEP-changes than patients with a single nerve lesion (85.7%; 6/7 nerves; vs. 34.2%; 13/38 nerves; Fisher's exact test, p < 0.05). With paired stimulation a suppression of the amplitude of N20, P25 and P45 (p < 0.05; sign test), and a marked increment of N35 (p < 0.05; sign test) and N60 (not significant; sign test) of the second response could be observed.

Conclusion: The results of the present investigation do not provide evidence of collateral innervation of peripherally denervated cortical neurons by neurons of adjacent cortical representation areas. They rather suggest that secondary components of the excitatory response to nerve stimulation are lost in cortical areas, which surround the denervated region.

No MeSH data available.


Related in: MedlinePlus

Influence of paired stimulation on SEP-components. Paired stimulation of the right median nerve with an inter-stimulus interval of 150 msec in a healthy subject. N20, P25 and P45 are depressed while N35 and N60 increase after the second stimulus.
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Figure 2: Influence of paired stimulation on SEP-components. Paired stimulation of the right median nerve with an inter-stimulus interval of 150 msec in a healthy subject. N20, P25 and P45 are depressed while N35 and N60 increase after the second stimulus.

Mentions: With paired stimulation a suppression of N20, P25 and P45 (p < 0.05; sign test), and a marked increment of N35 (p < 0.05; sign test) of the second response could be observed (Figures 2 and 3).


Changes of medium-latency SEP-components following peripheral nerve lesion.

Stendel R, Jahnke U, Straschill M - J Brachial Plex Peripher Nerve Inj (2006)

Influence of paired stimulation on SEP-components. Paired stimulation of the right median nerve with an inter-stimulus interval of 150 msec in a healthy subject. N20, P25 and P45 are depressed while N35 and N60 increase after the second stimulus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1636633&req=5

Figure 2: Influence of paired stimulation on SEP-components. Paired stimulation of the right median nerve with an inter-stimulus interval of 150 msec in a healthy subject. N20, P25 and P45 are depressed while N35 and N60 increase after the second stimulus.
Mentions: With paired stimulation a suppression of N20, P25 and P45 (p < 0.05; sign test), and a marked increment of N35 (p < 0.05; sign test) of the second response could be observed (Figures 2 and 3).

Bottom Line: Surprisingly 16 of the 29 patients (55.2%) showed a reduction or elimination of N35, P45 and N60.With paired stimulation a suppression of the amplitude of N20, P25 and P45 (p < 0.05; sign test), and a marked increment of N35 (p < 0.05; sign test) and N60 (not significant; sign test) of the second response could be observed.The results of the present investigation do not provide evidence of collateral innervation of peripherally denervated cortical neurons by neurons of adjacent cortical representation areas.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany. ruediger.stendel@charite.de

ABSTRACT

Background: Animal studies have demonstrated complex cortical reorganization following peripheral nerve lesion. Central projection fields of intact nerves supplying skin areas which border denervated skin, extended into the deafferentiated cortical representation area. As a consequence of nerve lesions and subsequent reorganization an increase of the somatosensory evoked potentials (SEPs) was observed in cats when intact neighbouring nerves were stimulated. An increase of SEP-components of patients with nerve lesions may indicate a similar process of posttraumatic plastic cortical reorganization.

Methods: To test if a similar process of post-traumatic plastic cortical reorganization does occur in humans, the SEP of intact neighbouring hand nerves were recorded in 29 patients with hand nerve lesions. To hypothetically explain the observed changes of SEP-components, SEP recording following paired stimulation of the median nerve was performed in 12 healthy subjects.

Results: Surprisingly 16 of the 29 patients (55.2%) showed a reduction or elimination of N35, P45 and N60. Patients with lesions of two nerves showed more SEP-changes than patients with a single nerve lesion (85.7%; 6/7 nerves; vs. 34.2%; 13/38 nerves; Fisher's exact test, p < 0.05). With paired stimulation a suppression of the amplitude of N20, P25 and P45 (p < 0.05; sign test), and a marked increment of N35 (p < 0.05; sign test) and N60 (not significant; sign test) of the second response could be observed.

Conclusion: The results of the present investigation do not provide evidence of collateral innervation of peripherally denervated cortical neurons by neurons of adjacent cortical representation areas. They rather suggest that secondary components of the excitatory response to nerve stimulation are lost in cortical areas, which surround the denervated region.

No MeSH data available.


Related in: MedlinePlus