EP 39. The modified ultrasound pattern sum score mUPSS as additional diagnostic tool for genetically distinct hereditary neuropathies

• Published in: Clinical neurophysiology 2016-09, Vol.127 (9), p.e254-e255
• Main Authors: Grimm, A, Decard, B, Rasenack, M, Axer, H
• Format: Article
• Language: English
• Subjects: Neurology
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2016.05.094

Objective To evaluate the peripheral nerve ultrasound characteristics in genetically distinct inherited neuropathies, the value of the modified ultrasound pattern sum score (mUPSS) to differentiate between the subtypes and the correlation of ultrasound with nerve conduction studies (NCS), disease duration and severity. Method All patients underwent a standardized neurological examination, ultrasound, and NCS. In addition, genetic testing was performed. Consequently, mUPSS was applied, which is a sum-score of cross sectional areas (CSA) at predefined anatomical points in different nerves. Results 31 patients were included (10xCharcot-Marie-Tooth (CMT)1a, 3xCMT1b, 3xCMTX, 9xCMT2, 6xHNPP). Generalized, homogeneous nerve enlargement and significantly increased UPS-scores emphasized the diagnosis of demyelinating neuropathy, particularly in CMT1a and CMT1b. The amount of enlargement did not depend on disease duration, symptom severity, height and weight.In CMTX the nerves were enlarged, as well, however only in the roots and lower limbs, most prominent in men. In CMT2 no significant enlargement was detectable ( Figs. 1 and 2 ). In HNPP the CSA values were increased at entrapped sites, and not elsewhere. However, a distinction from CMT1, which also showed enlarged CSA values at entrapment sites, was only possible by calculating the entrapment-ratios and entrapment-score. The mUPSS allowed distinction between CMT1a (increased UPS-scores, entrapment-ratios < 1.0) and HNPP (low UPS-scores, entrapment-ratios > 1.4), while CMT1b and CMTX showed intermediate UPS-types and entrapment-ratios < 1.0. Discussion Ultrasound of the nerves shows consistent and homogeneous nerve alteration in certain inherited neuropathies. By the use of the modified UPSS a quantitative tool for diagnosis, distinction and follow-up evaluation is available in addition to molecular testing.