The results from the electrodiagnostic (ED) studies showed that 16% of patients with electroclinical UNE were not diagnosed by the use of only two stimulation sites below and above the ulnar groove. Consequently, we will advocate three stimulation sites in the elbow. Smaller distances in segmental nerve conduction studies are probably safe with modern electrodiagnostic equipment . Recording from ADM and FDI gave very much the same results, as shown in Table 2[17–19]. Conduction velocity in the forearm while recording from ADM was abnormal in 21% of the patients, most probably caused by pronounced axonal degeneration in the nerve. We found a significant correlation between no pain in the elbow and decreased MCV above sulcus, which may indicate that entrapment in the ulnar groove is less painful than in the cubital tunnel. Blocking of thin myelinated A-delta fibres can explain this association. A general lack of correlation between pain and ED is not unexpected as thin-fibres function is not reflected in CV parameters. However, we could not confirm that patients with pain should be less likely to show abnormal CV for the majority of parameters.
Fibres to FDI may be more susceptible to demyelination compared to fibres to ADM . However, only 2.3% of the patients had normal results in the ADM recording and abnormal findings in the FDI recording. The most cost-effective procedure is consequently to use only ADM recordings, with optional recording over FDI, and additional use of the inching technique [6, 8] in selected cases. The advantages of the new protocol are that it can be performed as a screening test by the neurophysiology technicians. There is less risk of electrical spreading due to longer distances between the nerve stimulation points (six and four cm), while the segment steps in the inching technique are one or two cm. However, this study did not aim to compare the new protocol and the well known inching technique. Inching is also a superior technique in experienced hands for precise localization of ulnar nerve entrapment at the elbow.
Significant conduction block (amplitude decrement > 40%) at the elbow were found in 26% of the patients. This is a definite sign of nerve entrapment, but it was a rather infrequent finding in this UNE study, and it was not related to symptom duration. In another study  of 244 UNE patients 16% had motor conduction block (amplitude decrement ≥ 50).
The sensory nerve from the fifth finger was abnormal in 39% of the patients, and 30% had an abnormal dorsal ulnar nerve study. These results are in contrast to the large prevalence of sensory symptoms as 96% reported ulnar paresthesias and 86% had objectively reduced ulnar sensitivity in the hands. This discrepancy can be explained by a selection bias because patients with more severe symptoms and signs tend to be admitted for electrodiagnostic studies. The ulnar sensory findings in UNE patients in other studies vary from zero abnormal distal findings  to 51 - 55% abnormal sensory studies across the elbow [7, 22]. However, even if sensory studies do not contribute much to the sensitivity of the electrodiagnostic evaluation, they are useful to document axonal degeneration or severe dispersion within sensory fascicles.
We found abnormal EMG in about 50 percent of the UNE patients and abnormal MCV (as opposed to conduction block) was moderately associated with an increased rate of neuropathic EMG. Bhala  found abnormal EMG in 78 percent of patients with reduced NCV < 45 m/s) across the elbow with the highest abnormality rate in FDI. However, in our study only 31% of the UNE patients had EMG from ADM (53% abnormal), while 98% had EMG from FDI (49% abnormal). A more balanced examination rate might have changed these figures.
Clinical findings and previous diseases
Ninety-six percent of the UNE patients reported paresthesias in the ulnar territory, 86% had objectively reduced ulnar sensitivity in the hand, 48% had reduced ulnar muscle strength and 41% had pain in the elbow. Similar findings occurred among patients who had 290 surgical procedures for UNE . In only 6% of our patients we found reduced skin sensitivity outside the ulnar territory in the hand and 16% reported reduced sensitivity distal/medial in the forearm, which may be caused by a different anatomical nerve distribution or an unspecific pain-related dysfunction, as there were no clinical or electrodiagnostic evidence for another diagnosis in these patients. According to the inclusion criteria only patients with abnormal neurophysiological values of the ulnar nerve were included. Suspected UNE patients with normal electrodiagnostic values were consequently not included, and the symptom distribution and neurological findings might have been different with other inclusion criteria.
The frequency of previous CTS (3.9%)  and diabetes mellitus (7.1%) [26, 27] were close to prevalences within the general population. Unexpectedly, only 4% had had trauma to the elbow. Ten percent had had neck symtoms, which is very common in the Norwegian society. Consequently, UNE in this study seemed to be a singular condition probably caused by injury of the nerve, statical flexed position of the elbow, simple overuse of one arm, genetic predisposition, or an inflammation or another local disease in the elbow region .
We found 79% subjectively affected left ulnar nerves and only 21% affected right nerves. Left ulnar nerve dominance in UNE is also found in other studies . The right hand is dominant in most people and logically one would have expected the opposite, if ordinary work played a major role in the pathogenesis, which is found in CTS . In this study UNE prevailed in men (67%), in concert with other studies [4, 19, 24, 29]. Matev  reported that the ulnar nerve in men is more mobile and therefore more sensitive to gliding impairment at the medial epicondyle.
The use of electrodiagnosis in UNE
Differential diagnosis involves many diseases concerning the spinal cord, cervical roots and other peripheral entrapment sites. Consequently, clinical findings and tests in our opinion are not sufficient to make a qualified diagnosis of UNE. In the literature most surgeons advocate electrodiagnosis for UNE , but others prefer clinical testing without electrodiagnosis . Especially before surgery one should produce direct evidence for entrapment of the ulnar nerve at the elbow and single out other possible etiologies. Electrodiagnosis before surgery is also recommended in order to have a valid baseline for further studies on patients with residual symptoms after surgery. Patients might be in doubt whether to have an operation or not, and results from a nerve conduction study can help him/her to decide. Nonoperative management can also be successful, especially in patients with symptoms only .
There is no useful clinical gold standard for the diagnosis of UNE. Attempts to define gold standards based on operative success will also fail because peroperative complications, placebo effects and spontaneous remissions will interfere. Appropriately performed nerve conduction methods, used for more than 50 years, have proved to be very reliable, and most experts consider a combination of clinical and electroneurographic signs as a "gold standard" for the most common entrapments. Accordingly, we chose to apply electroclinical diagnostic inclusion criteria in the present study. The advantage is that the diagnostic precision is optimized, as it is recommended for the diagnosis of UNE . We could accordingly compare sensitivities among the various extended parameters. However, it should be noted that the comparison between standard and extended parameters in the present study could have been biased in favor of the standard parameters because they were among the inclusion criteria.
In addition we did not study other groups and could accordingly not estimate specificities of the extended electrodiagnostic parameters. Inclusion of patients with a clinical picture suggestive of UNE without neurophysiological evidence of entrapment (using the standard protocol) would have enabled us to also estimate specificities. However, it should be noted that interpretation of specificity is somewhat ambiguous when a definite gold-standard does not exist. Indeed, it will be difficult to differ between true and false positives in a population with symptoms suggesting UNE. Accordingly, specificity should also be calculated in a healthy control group and preferably, in a group with different symptomatology, for instance carpal tunnel syndrome. The lack of such control groups is a weakness of the present study. Accordingly, we recommend to perform such controlled studies, as well as prospective studies, in order to estimate specificities for our extended electrodiagnostic parameters in different groups, as well as the prognostic value of the extended parameters.