The purpose of this study is to learn about focal compressive median neuropathy at the wrist (Carpal Tunnel Syndrome) and outcomes of therapies (e.g. conservative and surgery) in the upper extremities of patients diagnosed with an inherited neuropathy. All patients enrolled in the Rare Diseases Clinical Research Network (RDCRN) Inherited Neuropathies Consortium (INC) Contact Registry who have marked one of the following disorders: CMT1A, CMT1B, CMT2A, CMT4, CMTX, other known CMT peripheral neuropathy, other unknown CMT peripheral neuropathy, or Hereditary Neuropathy with liability to Pressure Palsies (HNPP), will be invited via email to participate in this online study.

An online survey will be used to assess outcomes in conservative and surgical therapies used for carpal tunnel syndrome (CTS) in patients with a diagnosis of inherited neuropathy such as CMT or HNPP (Charcot-Marie-Tooth disease and Hereditary Neuropathy with liability to Pressure Palsies respectively). HNPP is an inherited neuropathy which is allelic to CMT1A. This patient reported outcome measurement will also assess symptom severity and functional status related to carpal tunnel syndrome (CTS) in various types of patients with inherited neuropathy.

The survey incorporates two validated questionnaires for the evaluation of outcomes related to carpal tunnel syndrome. The Boston Carpal Tunnel Questionnaire (BCTQ) is very specific to carpal tunnel syndrome (CTS). The Disability of Arm, Shoulder and Hand (DASH) questionnaire is less specific for CTS but has been shown to have equal validity in the assessment of outcomes in CTS. The relative non-specificity of DASH for CTS can be useful in assessing the possible contribution of CMT to the overall upper extremity symptom severity and functional outcome. Data collected from participants with a diagnosis or therapies for CTS can be compared to data collected from participants with no diagnosis or therapies for CTS.

Furthermore, the study will incorporate components from the CMTNS to assess the extent of CMT disease in the participants.

It is proposed that a retrospective analysis of patients with CMT who have symptoms in the upper extremities suggestive of carpal tunnel syndrome. Two validated questionnaires exploring changes in symptoms and functional status (BCTQ and DASH) can be used in evaluating outcomes of patients with reported symptoms or diagnosis of carpal tunnel syndrome.

The Boston Carpal Tunnel Questionnaire (BCTQ) is a 19 item scale which was developed specifically for carpal tunnel syndrome and consists of 11 questions to assess symptom severity and 8 questions to assess functional status. BCTQ has established test-retest reliability with a good Pearson's correlation of scores on re-test (0.91 for the symptoms severity component and 0.93 for the functional status component of the test). High internal consistency has also been reported for the BCTQ (0.88-9.92). Convergent validity has been demonstrated with high correlation between pre- and postoperative BCTQ scores and physical measures such as grip, key pinch and three-jaw pinch. Responsiveness of the BCTQ after carpal tunnel surgery has been demonstrated in randomized clinical trial settings. BCTQ has also been reported to be 2-4 times more responsive to clinical improvement in comparison to measures of neuromuscular impairment. High response rates have been reported with BCTQ with 80-93% at 6-12 weeks follow-up and between 67-93% at 6-12 months follow-up after carpal tunnel release. Response rates remained high at 85% at 2 years follow-up. Mailed follow-up response rate of 69% has been reported with a mean follow-up of 4.8 years. The mean time to complete BCTQ has been reported to be 5.6 minutes. There is no data to indicate the precision of BCTQ in relation to carpal tunnel syndrome.

The Disability of Arm, Shoulder and Hand (DASH) questionnaire is a 30 item scale which assesses symptoms and physical function. This questionnaire is not specific for carpal tunnel and can be used for a variety of disorders affecting the upper limb. DASH is intended to measure disability through an emphasis on upper extremity activity. The test-retest reliability of DASH has been demonstrated with a Pearson's 8 correlation of 0.9 in a group of patients with carpal tunnel syndrome.

The validity of DASH was demonstrated through correlation with BCTQ. Pre- and postoperative DASH scores also correlate with physical measures such as grip, key pinch and three-jaw pinch. Responsiveness through improved DASH scores has been demonstrated at three and six months post-surgery follow-up. BCTQ was found to be more responsive to DASH for carpal tunnel syndrome. Postal mail response rates have been shown to be 80-93% at 6-12 weeks and 66-98% at 6 months after carpal tunnel release. The mean time to complete DASH is reported to be 6.8 minutes. There is no data to indicate the precision of DASH in relation to carpal tunnel syndrome.

The survey data will be stored by the Rare Diseases Clinical Research Network's Data Management and Coordinating Center (DMCC) at the University of South Florida. Names or other personal health information will not be collected. Upon conclusion of the study period, the data will be sent to Dr. Michael Shy, principal investigator of the Inherited Neuropathies Consortium. Deidentified data will be sent to the database of Genotypes and Phenotypes (dbGaP).

Inclusion Criteria:

• Diagnosis of CMT or HNPP
• Adults age 18 years and older
• Self-Registration at the Inherited Neuropathies Consortium (INC) Contact Registry

Exclusion Criteria:

• Inability to provide informed consent and complete survey
• Inability to read or speak English

The online survey will target adult CMT patients who have self-registered at the RDCRN Inherited Neuropathies Consortium (INC) Contact Registry, a web based contact registry developed and supported by the RDCRN Data Management and Coordinating Center (DMCC), located at the University of South Florida.