Comfort Thresholds for Repetitive Forces
Comfort During Prolonged Exposure to Repetitive Forces Mimicking Exoskeleton Use
Exoskeletons can be used for rehabilitation, as assistive device for patients, or to support workers during strenuous tasks. To fulfil their purpose, they need to apply forces to the user's musculoskeletal system. The forces are transmitted at skin level through an interface, often in the form of cuffs. Adverse events causing discomfort and injuries to the skin and underlying tissue can be attributed to those interaction forces. While there is some information about safe limit values for impact forces or pressure and shear applied for short durations, little is known regarding comfort and safety thresholds for repetitive forces applied over long durations as is the case in exoskeleton use. This study therefore aims at gaining new knowledge on safe and limit values, based on discomfort (staying below pain threshold), for continuous repetitive shear and normal forces applied through a cuff.
Therefore, the primary objective is to determine comfort thresholds for prolonged exposure to repetitive normal and shear stress exerted to the human thigh via a cuff with straps, using different force patterns comparable to those exerted during exoskeleton use. The secondary objectives are to determine the feasibility of the experiment, the influence of subject characteristics on comfort thresholds, the occurrence of skin injuries or other negative signs, and whether characteristics of muscle activity can be related to discomfort.
Descripción general del estudio
Estado
Condiciones
Intervención / Tratamiento
Descripción detallada
Rationale: Exoskeletons can be used for rehabilitation, as assistive device for patients, or to support workers during strenuous tasks. To fulfil their purpose, they need to apply forces to the user's musculoskeletal system. The forces are transmitted at skin level through an interface, often in the form of cuffs. Adverse events causing discomfort and injuries to the skin and underlying tissue can be attributed to those interaction forces. While there is some information about safe limit values for impact forces or pressure and shear applied for short durations, little is known regarding comfort and safety thresholds for repetitive forces applied over long durations as is the case in exoskeleton use. This study therefore aims at gaining new knowledge on safe and limit values, based on discomfort (staying below pain threshold), for continuous repetitive shear and normal forces applied through a cuff.
Objective: The primary objective is to determine comfort thresholds for prolonged exposure to repetitive normal and shear stress exerted to the human thigh via a cuff with straps, using different force patterns comparable to those exerted during exoskeleton use. The secondary objectives are to determine the feasibility of the experiment, the influence of subject characteristics on comfort thresholds, the occurrence of skin injuries or other negative signs, and whether characteristics of muscle activity can be related to discomfort.
Study design: The study is a cross-sectional intervention study with one measurement session, where participants will provide a continuous comfort rating during exposure to repetitive normal and shear forces.
Study population: The aim is to include 20 healthy participants in total, matching the age groups 18-35 and 55-85.
Intervention: A pre-defined set of prolonged repetitive force patterns will be applied to each participant's thigh though a contact force which is similar to cuffs commonly used in gait exoskeletons. The forces will be applied by a custom made actuated test device and are based on normal use of exoskeletons.
Main study parameters/endpoints: The main study parameter is the level of discomfort as indicated continuously by the participants through a slider with a visual analogue scale. The scale reaches from no discomfort at all to maximum imaginable discomfort. A separate switch which releases all forces if activated by the participant is used to detect onset of pain.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The study is non-therapeutic, so no direct benefits for the participants are involved. The procedures are non-invasive and safety measures are taken to avoid excessive force exertion to the participants or other unsafe situations. Therefore, subjects suffer no negative effects or disadvantages, except for the invested time and the discomfort experienced during the force execution. Pain will be avoided as participants can trigger a release of the forces at any time. Any changes to the participants' skin or other negative signs will be monitored and followed up on until they have resolved.
Tipo de estudio
Inscripción (Actual)
Fase
- No aplica
Contactos y Ubicaciones
Ubicaciones de estudio
-
-
-
Enschede, Países Bajos
- Roessingh Research and Development
-
-
Criterios de participación
Criterio de elegibilidad
Edades elegibles para estudiar
Acepta Voluntarios Saludables
Géneros elegibles para el estudio
Descripción
Inclusion Criteria:
- Between 18 and 35 or between 55 and 85 years of age
- Able to provide informed consent
Exclusion Criteria:
- Unable to follow simple instructions
- Insufficient knowledge of the Dutch or English language to understand the purpose and methods of the study
- skin lesions at the thigh
- sensory impairments
- severe blood pressure fluctuations
- inability to sit in required posture in experiment chair for 60 minutes
- taking blood thinners or showing signs for increased bleeding tendency
Plan de estudios
¿Cómo está diseñado el estudio?
Detalles de diseño
- Propósito principal: Otro
- Asignación: N / A
- Modelo Intervencionista: Asignación de un solo grupo
- Enmascaramiento: Ninguno (etiqueta abierta)
Armas e Intervenciones
Grupo de participantes/brazo |
Intervención / Tratamiento |
|---|---|
|
Experimental: Study group
All participants in the study will receive the same investigational treatment (application of prolonged repetitive forces) and provide continuous comfort ratings.
|
The investigational treatment consists of applying a predefined set of continuous and repetitive forces to the participant's thigh.
It is applied using a custom device that has been designed specifically for this study.
The forces to be applied are based on forces measured during exoskeleton use and will not exceed pain pressure thresholds reported in literature.
The participants will hold an enabling switch at all times which they can activate to release the force exerted to their thigh.
Alternatively, the experimenter can activate an emergency switch if the situation seems unsafe.
|
¿Qué mide el estudio?
Medidas de resultado primarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
|
Perceived discomfort as indicated on a 10 mm visual analog scale (VAS) by the participants, ranking from 'no discomfort' to 'worst imaginable comfort' (10)
Periodo de tiempo: 80 minutes
|
The level of discomfort will be indicated on a VAS as a percentage of maximum imaginable discomfort through a slider that is positioned within reach of the subjects.
It will be synchronized with the forces exerted in relation to time.
The onset of discomfort, i.e. the point at which the slider of the VAS is first moved to a position >0, is recorded as discomfort detection threshold (DDT).
If the participant activates the enabling switch indicating that the force creates pain rather than discomfort, this point is recorded as pain detection threshold (PDT).
|
80 minutes
|
Medidas de resultado secundarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
|
Number of completed test sessions/dropouts
Periodo de tiempo: 160 minutes
|
To investigate feasibility and tolerability of experiments
|
160 minutes
|
|
Occurrence of injuries or other negative signs
Periodo de tiempo: 30 minutes
|
Records of skin changes directly after the sessions and short structured interview on the phone 2-4 days after the intervention
|
30 minutes
|
|
Surface Electromyography (EMG) recordings of Rectus femoris
Periodo de tiempo: 120 minutes
|
Muscle activity
|
120 minutes
|
Otras medidas de resultado
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
|
Height in meters
Periodo de tiempo: 2 minutes
|
Height and weight will later be combined to report BMI in kg/m²
|
2 minutes
|
|
Body weight in kg
Periodo de tiempo: 2 minutes
|
Height and weight will later be combined to report BMI in kg/m²
|
2 minutes
|
|
Age in years
Periodo de tiempo: 1 minute
|
Age will reported as one subject characteristic
|
1 minute
|
|
Gender
Periodo de tiempo: 1 minute
|
Gender will be reported as one subject characteristic
|
1 minute
|
Colaboradores e Investigadores
Patrocinador
Fechas de registro del estudio
Fechas importantes del estudio
Inicio del estudio (Actual)
Finalización primaria (Actual)
Finalización del estudio (Actual)
Fechas de registro del estudio
Enviado por primera vez
Primero enviado que cumplió con los criterios de control de calidad
Publicado por primera vez (Actual)
Actualizaciones de registros de estudio
Última actualización publicada (Actual)
Última actualización enviada que cumplió con los criterios de control de calidad
Última verificación
Más información
Términos relacionados con este estudio
Palabras clave
Otros números de identificación del estudio
- 80800
Plan de datos de participantes individuales (IPD)
¿Planea compartir datos de participantes individuales (IPD)?
Información sobre medicamentos y dispositivos, documentos del estudio
Estudia un producto farmacéutico regulado por la FDA de EE. UU.
Estudia un producto de dispositivo regulado por la FDA de EE. UU.
Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .