Back to Search Start Over

A quantitative measure of handgrip myotonia in non-dystrophic myotonia.

A quantitative measure of handgrip myotonia in non-dystrophic myotonia.

Authors :
Statland JM
Bundy BN
Wang Y
Trivedi JR
Raja Rayan D
Herbelin L
Donlan M
McLin R
Eichinger KJ
Findlater K
Dewar L
Pandya S
Martens WB
Venance SL
Matthews E
Amato AA
Hanna MG
Griggs RC
Barohn RJ
Source :
Muscle & nerve [Muscle Nerve] 2012 Oct; Vol. 46 (4), pp. 482-9.
Publication Year :
2012

Abstract

Introduction: Non-dystrophic myotonia (NDM) is characterized by myotonia without muscle wasting. A standardized quantitative myotonia assessment (QMA) is important for clinical trials.<br />Methods: Myotonia was assessed in 91 individuals enrolled in a natural history study using a commercially available computerized handgrip myometer and automated software. Average peak force and 90% to 5% relaxation times were compared with historical normal controls studied with identical methods.<br />Results: Thirty subjects had chloride channel mutations, 31 had sodium channel mutations, 6 had DM2 mutations, and 24 had no identified mutation. Chloride channel mutations were associated with prolonged first handgrip relaxation times and warm-up on subsequent handgrips. Sodium channel mutations were associated with prolonged first handgrip relaxation times and paradoxical myotonia or warm-up, depending on underlying mutations. DM2 subjects had normal relaxation times but decreased peak force. Sample size estimates are provided for clinical trial planning.<br />Conclusion: QMA is an automated, non-invasive technique for evaluating myotonia in NDM.<br /> (Copyright © 2012 Wiley Periodicals, Inc.)

Details

Language :
English
ISSN :
1097-4598
Volume :
46
Issue :
4
Database :
MEDLINE
Journal :
Muscle & nerve
Publication Type :
Academic Journal
Accession number :
22987687
Full Text :
https://doi.org/10.1002/mus.23402