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Everything you always wanted to know about nerve, but were afraid to ask
| Content Provider | Semantic Scholar |
|---|---|
| Author | Padua, Luca |
| Copyright Year | 2012 |
| Abstract | In this issue there is an article by Datema and colleagues (Datema et al., 2012) on the diagnostic yield of Neuropads and water immersion skin wrinkling (WISW) for the diagnosis of small fiber neuropathy (SFN). Neuropads and WISW have been tested on patients affected with different forms of clinically diagnosed (on the basis of symptoms) small fiber neuropathy, and healthy controls. The first thought that came to me reading this article is that we still often evaluate sensitivity and specificity of neurophysiological tests on the basis of clinical examination and symptoms. So why should we need diagnostic tests? We need them because we do not really think that clinical diagnosis alone can be a gold standard and we search for a gold standard ‘‘test’’ that would provide more standardized results than clinical presentation. I myself agree with the need of diagnostic/confirmatory/supporting tests. I also believe that we should talk more about this topic and open a debate in this journal focused on neurophysiological tests. The paper by Datema and colleagues (Datema et al., 2012) has the merit of dealing with a part of the peripheral nervous system that is often overlooked or less investigated: small fibers. And they do it through simple tests (!) while instead we tend to neglect things that are difficult to investigate. Much of a nerve and much of its function are usually not evaluated. When we deal with the peripheral nerve we usually record the maximal conduction velocity and the evoked response. Working with these measures we are self-confident thanks to our knowledge, and we often try to improve what does not really need to be improved, because the sensitivity is usually high and further improvement might decrease the specificity of the test. However, we are aware that neurophysiology routinely performed in an EMG lab does not assess many of the diseases that we deal with every day. The peripheral nerve diseases that we commonly encounter in an EMG lab are: entrapments (mainly carpal tunnel syndrome), radiculopathies due to spinal disease, polyneuropathies, and traumatic nerve lesions. Concerning the first, tests are now very sensitive. (I still have to determine whether the improvement in sensitivity in the diagnosis of carpal tunnel syndrome, to which my group has contributed, gave benefit to the patients or only increased surgical procedures that could be avoided; I hope the first). Concerning radiculopathies, we justify ourselves due to the inability to interpret the negative EMG (even in the presence of severe symptoms) as ‘‘no axonal damage occurs’’. However we should instead try to identify an index of root involvement, because if symptoms occur, something is going on in the nerve. Concerning polyneuropathies, conventional tests may be neurophysiologically normal even in symptomatic patients. Elegant studies have demonstrated that nerve conduction velocities become abnormal only when a large proportion of the large fibers is severely involved (Caliandro et al., 2007). Not always is the whole nerve involved in peripheral nerve disease (Bosboom et al., 2001). Concerning traumatic nerve lesions, we have accepted the limitations of the neurophysiology, which is unable to distinguish between axonotmesis and neurotmesis, two conditions that need quite different therapeutic approaches. A mistake in this field may have serious effects on patient’s ability and Quality of Life. Ultrasound is considered a new tool of the neurophysiology, but is readily available (Padua and Martinoli, 2008). There are many things we want to know about the nerve and we are afraid to ask because they are difficult to investigate. Small fibers, not faster conducting fibers, unmyelinated fibers, skin receptors, extreme peripheral nerve segments, etc. are likely responsible for most of the diseases and dysfunctions that we are not able to assess. Scattered papers are published and several tests are developed to assess the properties and functions of the small fibers and the elusive portions of the nerve that we are discussing here (I do not want to quote some of them because I am sure that I will omit many others), but they often remain on the ‘‘periphery’’ of the field in which we are working. The EMG community has to face this problem, and must be prepared to study these nerve segments and their function, developing new techniques that are easier to use or adopting those that have already been developed. The following are some possible paths that can be taken: |
| Starting Page | 1902 |
| Ending Page | 1903 |
| Page Count | 2 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/j.clinph.2012.02.080 |
| PubMed reference number | 22465416 |
| Journal | Medline |
| Volume Number | 123 |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/S1388245712002167 |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/S1388245712002167?dgcid=api_sd_search-api-endpoint |
| Alternate Webpage(s) | https://doi.org/10.1016/j.clinph.2012.02.080 |
| Journal | Clinical Neurophysiology |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
