Quantitation of McArdle's Sign and Evaluation of Specificity for Multiple Sclerosis

Mayo Clinic

Status: Completed

Conditions: Multiple Sclerosis

Study type: Observational

Funder types: Other

Identifiers

NCT03122873

15-009122

Details and patient eligibility

About

The study is designed to quantitate McArdle's sign, an increase in measurable weakness with neck flexion described in patients with multiple sclerosis, and to determine whether it is or is not specific for multiple sclerosis.

Full description

Finger strength will be measure using a torque-measuring device designed to quantitate finger extension strength. The device was designed for point of treatment use, patient safety and portability. Strength will be measured in 5 paired trials, first with neck extended and then with neck flexed. Two protocols will be evaluated, one testing isometric strength against a fixed resistance and the second testing strength against dynamic resistance. McArdle's sign is the difference between strength with neck extension and strength with neck flexion.

The data will be digitally registered and dynamic neck position will be recorded electronically in real time. Graphs of dynamic changes in torque versus neck position will be generated and superimposed. Strength will be quantitated using Matlab software.

Consecutive patients with myelopathy of any cause with detectable finger extensor weakness will be studied, either due to MS or due to other cause of myelopathy (other inflammatory, vascular, compressive, neoplastic and other). Additionally, normal controls will be studied as will patients with finger extension weakness due to peripheral nerve lesions.

Enrollment: 125 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Myelopathy of any cause with finger extension weakness
• Patients with peripheral neuropathy with finger extension weakness
• Healthy controls

Exclusion criteria

• Pregnant subjects.

Trial design

125 participants in 3 patient groups

Myelopathy of any cause

Description:

Male or female 18 years or older with myelopathy and detectable finger extension weakness due to 1) prototypic multiple sclerosis (N=50) 2) other etiologies of myelopathy (N=50), including other inflammatory conditions (e.g. idiopathic transverse myelitis, neuromyelitis optica, acute disseminated encephalomyelitis, sarcoidosis) or other etiologies (compression, vascular disorders, degenerative disorders, neoplasms).

Peripheral neuropathy

Description:

Male or female 18 years or older with C7 radiculopathy, radial neuropathy, plexopathy, peripheral neuropathy, who have detectable finger extension weakness.

Healthy Controls

Description:

Male and female 18 year or older with no finger extension weakness and no known neurological conditions.