NCT00357058

Role of Brain Region Changes in Tactile (Touch) Ability Following Nerve Block

Completed Last updated 2 July 2017

What this trial tests

trial in Tactile Spatial Acuity in 90 participants. Completed in 28 December 2007.

Timeline

12 December 2001

28 December 2007

Quick facts

Lead sponsor	National Institute of Neurological Disorders and Stroke (NINDS)
Status	Completed
Study type	OBSERVATIONAL
Enrollment	90
Start date	12 December 2001
Estimated completion	28 December 2007
Sites	1 location across United States

Conditions studied

• Tactile Spatial Acuity — all drugs for Tactile Spatial Acuity →
• Healthy — all drugs for Healthy →

Sponsor

National Institute of Neurological Disorders and Stroke (NINDS)

Who can join

18 and older, any sex, with Tactile Spatial Acuity or Healthy. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

This study will examine the role of different brain regions in tactile (touch) ability after application of a tourniquet (inflated blood pressure cuff). When the forearm is deprived of blood for a short period of time, tactile ability in the other hand improves. This study will try to learn what causes this improvement.

Healthy normal volunteers are eligible for this study. Candidates will have a brief medical history and physical examination.

Volunteers will undergo two experiments, described below, that involve the following procedures:

* Ischemic nerve block - A blood pressure cuff is inflated for 35-40 minutes around the elbow area (also around the calf for Experiment 2 - see below). The resulting numbness, tingling, loss of muscle strength, and discoloration of the forearm and hand disappear within minutes after the cuff is deflated.
* Magnetic resonance imaging (MRI) - This test uses a magnetic field and radio waves instead of X-rays to produce images of brain structure and function. The volunteer lies on a stretcher that is moved into the scanner (a cylinder containing a strong magnet), wearing earplugs to protect the ears from loud thumping noises that occur with electrical switching of radio frequency circuits. The subject can communicate with an investigator by intercom at all times during the scan.
* Transcranial magnetic stimulation (TMS) - An insulated wire coil is placed on the patient's scalp. A brief electrical current passes through the coil, creating a magnetic pulse that travels through the scalp and skull and causes small electrical currents in the outer part of the brain. The stimulation may cause muscle hand or arm twitching or transient tingling in the forearm, head or face muscles.
* Tactile spatial acuity testing - The subject's left arm is placed in a cast and the left index finger is immobilized for this test which involves identifying the direction of grooves applied to the finger.

Experiment 1

This experiment measures changes in tactile acuity and brain activation following cuff inflation. The subject lies in the MRI scanner, with the left arm immobilized. Tactile acuity is measured repetitively at the left index finger during placement and inflation of a pressure cuff around the right forearm. The experiment consists of two sessions with the cuff around the forearm and one with the cuff around the calf and lasts from 90 minutes to 2 hours.

Experiment 2

This experiment measures changes in tactile acuity linked to TMS stimulation. The subject sits in an armchair with the left arm immobilized. Tactile acuity is measured repetitively at the left index finger during placement and inflation of a pressure cuff around the right forearm. In addition, TMS pulses (about one pulse per second) are delivered at different locations over the right side of the head for up to 30 minutes. The experiment consists of 10 separate sessions on different days, each lasting about 1 hour.

Publications & conference data

No peer-reviewed publications indexed yet for this trial. Completed trials usually publish results within 12-18 months.