Central pain location in SCN9A-associated SFN: an fMRI pilot study.

Recruitment & Eligibility

Status: Completed

Sex: Not specified

Target Recruitment: 60

Inclusion Criteria

Patient group (SCN9A-associated SFN) (n <= 20)
a. Male and/or female subjects between the ages of 18 and 80 years.
b. Presence of a clinical diagnosis of small fiber neuropathy, according to
international criteria and presence of confirmed abnormality on intra-epidermal
nerve fiber density evaluation and/or Quantitative Sensory Testing.
c. A mutation in the SCN9A gene, confirmed by sequencing, with possible,
probable or certain pathogenicity according to international criteria.
d. Presence of pain due to SFN for at least 3 months and an average
self-reported pain score of at least 5.
e. Subjects must give informed consent by signing and dating an informed
consent form., Patient group (SFN without a gene mutation)
a. Male and/or female subjects between the ages of 18 and 80 years.
b. Presence of a clinical diagnosis of SFN, according to international
criteria,1, 52, 53 including a decreased intra-epidermal nerve fiber density
IENFD in skin biopsy.
c. No mutation in the SCN9A, SCN10A or SCN11A gene, confirmed by sequencing.
d. Presence of pain due to SFN for at least 3 months and an average
self-reported pain score of at least 5.
e. Subjects must give informed consent by signing and dating an informed
consent form., Control group (n <= 20)
a. Male and/or female subjects between the ages of 18 and 80 years.
b. Subjects must give informed consent by signing and dating an informed
consent form.

Exclusion Criteria

A potential subject who meets any of the following criteria will be excluded
from participation in this study:
a. Major depression according to DSM-V criteria or a history of major
psychiatric disease.
b. (History with) alcohol abuse
c. Hospital Anxiety and Depression Scale (HADS) * 14
d. Subjects who have another pain syndrome than small fiber neuropathy.
e. Contraindications for undergoing MRI: pacemaker, metallic foreign body
(including aneurysm clip in the brain), claustrophobia, pregnancy,
neurostimulator, pacemaker or other kinds of implanted devices or insulin pump.
In case of cardiac valve replacement of ossicular replacement prosthesis the
radiologist will be consulted.

Study & Design

Study Type: Observational non invasive

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>Concerning the fMRI, change of connectivity in the central executive network<br /><br>(CEN) and sensorimotor network (SMN) is the primary endpoint.<br /><br>Change in brain connectivity have been observed in several neuropathic pain<br /><br>conditions affecting mainly the networks mentioned above: SMN tend to show<br /><br>hyperconnectivity while CEN hipoconnectivity. Concerning DTI, the study<br /><br>parameters are fractional anisotropy (FA) and axial diffusivity (AD).</p><br>

Secondary Outcome Measures