Descriptive Study of Receptive Fields in Lower Limb Amputees

Rehaklinik Bellikon35 enrolled

Overview

It has been observed that patients subjected to amputations develop so called receptive fields, which time of occurrence and localization over time are yet not examined systematically. This clinical trial aims to investigate the reliability in detecting these receptive fields as well as their incidence and changes over time. Further it aims to evaluate the acute effect of a stimulating system ("Phantom Stimulator" (Cort X Sensorics, Spaichingen, Germany)) on selected gait parameters measured tough a gait analysis system ("OprtoGait" (Microgate, Bolzano, Italy)) as well as on phantom sensations measured through a questionnaire.

It has been observed that patients subjected to amputations develop so called receptive fields, which time of occurrence and localization over time are yet not examined systematically. A receptive field is defined as skin area anywhere on the same side of the body as the amputation, which when stimulated by others, causes phantom sensations in the amputated extremity. This clinical trial aims to investigate the reliability in detecting these receptive fields as well as their incidence and changes over time. Further it aims to evaluate the acute effect of the stimulating system ("Phantom Stimulator" (Cort X Sensorics, Spaichingen, Germany)) on selected gait parameters measured tough a gait analysis system ("OprtoGait" (Microgate, Bolzano, Italy)) as well as on phantom sensations measured through a questionnaire.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

SCREENING

Masking

SINGLE

Enrollment

Conditions

Lower Limb Amputation Below Knee (Injury)

Interventions

Phantom Stimulator, Cort X Sensorics, Spaichingen, GermanyDEVICE

This system consists of a pressure sensing insole connected to regular TENS-Electrode patches which are applied to the receptive fields of the patients (evoking the sensation of heel and forefoot). The individually adjusted stimulation intensity on the systems regulatory box through a socked screw is set at the beginning of the testing phase, and not changed anymore. The current is applied to mimic the roll-off-sensation while walking. This is done by locating two sets of electrodes on the receptive fields representing the heel and the ball of the foot respectively. Now the current is applied in an alternating manner coordinated with the walking of the participant. The coordination is made able through the pressure sensing insole.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

1. Inclusion criteria for descriptive study: a. Lower limb amputation (independently of side or height of amputation) 2. Inclusion criteria for Phantom stimulator: 1. Receptive fields present at testing day 31 (last regular assessment of the receptive fields) 2. Lower limb amputation below the knee (if both sides the system is applied to the dominant side). 3. Exclusion criteria: 1. Implanted devices (defibrillator or pacemaker) 2. Pregnancy

Outcomes

Primary Outcomes

Description of receptive Fields Size in cm2

The primary outcomes are the changes in size over time. Here the size is described in cm2. The Fields size will be recorded by drawing them on the skin with eyeliner and subsequently taking photos. Later, these photos are analysed with the computer program Photoshop.

Time frame: 4-5 Weeks (7 hours)

Description of receptive Fields Position in % overlapping from first measurement

The primary outcomes are the changes in Position over time. Here the position is described in % overlapping with respect to the first measurement. The Fields position will be recorded by drawing them on the skin with eyeliner and subsequently taking photos. Later, these photos are put together and compared with the computer program Photoshop.

Time frame: 4-5 Weeks (7 hours)

Secondary Outcomes

Change in gait parameters through Phantom Stimulator

The secondary outcomes are the change in selected gait parameters through the application of the stimulating system ("Phantom Stimulator" (Cort X Sensorics, Spaichingen, Germany)). These parameters are measured with the gait analysis system Optogait. The selected parameters are step length (cm), width (cm), cadence (steps/min) and speed (m/s).

Time frame: 1/2 Day (3 hours)

Change in phantom sensations through Phantom Stimulator

The secondary outcomes are the change in phantom sensations through the application of the stimulating system ("Phantom Stimulator" (Cort X Sensorics, Spaichingen, Germany)). These changes are measured through a questionnaire witch uses the Visual Analogue Scale (values from 1 - 10).