Head Repositioning Accuracy During Experimental Neck Pain

Study Overview
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Brief Summary
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This study investigates if/how an experimentally applied neck muscle pain influences head repositioning error in healthy participants.

Detailed Description
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Healthy volunteers will participate in a single session study with a crossover design. During the study healthy participants will be randomized to either receive a injection of hypertonic saline (painful injection) or isotonic saline (control injection) in a neck muscle. Head repositioning accuracy will be assessed with and without performing a cognitive task.

Official Title
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Neck Pain - Motor and Sensory Aspects

Conditions
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Healthy, Neck Pain

Intervention / Treatment
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* Drug: Injection of hypertonic saline
* Drug: Injection of Isotonic saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy men and women aged 18-50 years Right handed Able to speak, read and understand Danish or English Normal pain free neck and shoulder range of motion Exclusion Criteria: Pain from the neck or shoulder area Prior surgery in neck or shoulder Pregnancy Drug addiction defined as the use of cannabis, opioids or other drugs Self reported neurologic, musculoskeletal or mental illnesses

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants will be randomized to either the painful condition or the control condition first before crossing over to opposite condition.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Painful condition<br>Participants will be injected with 0.5ml hypertonic saline (5.8%) into a neck muscle | Drug: Injection of hypertonic saline<br>* Painful condition: Participants will be injected in a neck muscle with 0.5ml of hypertonic saline (5.8%)<br>* Other names: Hypertonic saline (5.8%);|
| Experimental: Control condition<br>Participants will be injected with 0.5ml Isotonic saline (0.9%) into a neck muscle | Drug: Injection of Isotonic saline<br>* Control condition: Participants will be injected in a neck muscle with 0.5ml isotonic saline (0.9%)<br>* Other names: Isotonic saline (0.9%);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in head repositioning accuracy | Participants will be blindfolded and asked asked to, from a neutral position, to move the head into full range of motion before returning to to a neutral position again. The difference between the start and end position will be used as an estimate of head repositioning error. | Within session (session lasts approximately 2 hours) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in perceived pain | Pain will be scored using a scale from 0-10 with 0 being no pain and 10 being worst imaginable pain, by drawing on body charts and choosing words from the McGill Pain Questionnaire. | Within session (session lasts approximately 2 hours) | 
| Change in perceived performance of head repositioning accuracy test | Likert scores of the perceived difficultness (0=no problems, 1=minimally difficult, 2=somewhat difficult, 3=fairly difficult, 4= very difficult, 5=unable to perform) | Within session (session lasts approximately 2 hours) |