Clinical trial NCT05582616: The Safety and Feasibility of tDCS Combined With Conservative Treatment for Cervicogenic Headaches
Official title: The Safety and Feasibility of Transcranial Direct Current Stimulation Combined With Conservative Treatment for Cervicogenic Headaches
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Cervicogenic Headache
Keywords: Transcranial Direct Current Stimulation
Physiotherapy
Lead sponsor: University of Calgary
Sponsor class: OTHER
Collaborators: name: Alberta Health services
First posted: 2022-10-17
Enrollment: 32
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Double blind randomized placebo controlled clinical trial.
Primary purpose: TREATMENT

Brief summary: Annually, up to 150,000 individuals are affected by cervicogenic headaches (CGH) in Canada with many of these cases being chronic. Current treatments for CGH are limited in efficacy and durability - indicating a dire need for novel interventions in this population. Transcranial direct current stimulation (tDCS) and physiotherapy have a high degree of safety and have been studied as interventions for many other chronic pain conditions and headache disorders. We propose to study the feasibility and safety of tDCS alongside physiotherapy for CGH further in a randomized sham controlled trial.

Detailed description: Annually, up to 150,000 people in Canada and experience cervicogenic headaches (CGH) with many of these patients suffering from chronic CGH. CGH is a pain disorder where pain is perceived in the head but caused by dysfunction of the cervical spine and its anatomical structure. More specifically, the pathogenesis of CGH is due to the convergence of nociceptive afferents from the upper three cervical nerves and trigeminal nerves onto second-order neurons in the trigeminocervical nucleus. The pain signaling resulting from this is also modulated through sensorineural pathways involving the thalamus and the sensorimotor cortex. As such symptoms of CGH include restricted movement, local tenderness of the upper cervical spine joints, musculoskeletal impairments, headache, local pressure hyperalgesia and bilateral thermal hypoesthesia. To date, there is no "cure" for chronic CGH and current treatment entails trial and error with behavior management, environmental modifications and medications. Consequently, there is a significant need for new approaches to symptom management in order to help improve functional impairment and disease burden associated with treating CGH. Transcranial direct current stimulation (tDCS) and physiotherapy have a high degree of safety and have been studied as an intervention for many other chronic pain conditions and headache disorders, including arthritis and migraines, demonstrating considerable potential. The investigators propose to study the safety and feasibility of tDCS alongside physiotherapy as a treatment for CGH in a randomized sham controlled trial.

RESEARCH QUESTIONS AND OBJECTIVES

The overall objective is to study the feasibility and safety of tDCS applied to the primary motor cortex in patients with CGH and to explore whether active tDCS augments the effect of rehabilitation therapy.

Specifically the objectives are:

Primary Objective: To determine whether active tDCS is feasible and safe compared to sham when administered with rehabilitation therapy for patients with CGH when administered 3 times per week over the course of 6 weeks. Safety will be measured through serious adverse events (defined as events requiring medical attention). Feasibility will be measured by recruitment (greater than 30%), retention (greater than 80%), and adherence (greater than 70%). These outcomes will be measured throughout the treatment process up to immediately post-treatment.

Secondary Objective: To determine what secondary outcomes such as quality of life, headaches, pain sensitivity, neck mobility, anxiety, and depression improve with active tDCS treatment in individuals suffering with CGH. Quality of life will be measured via the European Quality of Life Five Dimension (EQ-5D), headache intensity, frequency, duration, and impacts on life will be measured via headache diaries and the Headache Intensity Test - 6 (HIT-6), headache effects on participant function will be measured via the Headache Disability Index (HDI), neck pain intensity will be measured through the numeric pain rating scale (NPRS), pain sensitivity will be measured via the Pain Sensitivity Questionnaire (PSQ), pain impacts on quality of life will be measured through the patient reported outcomes measurement information system - pain interference scale (PROMIS-PI), neck mobility will be measured through various motor control, strength, and endurance tests, feelings of depression will be measured via the PHQ-9 and anxiety via the GADS-7 before treatment after treatment and at 6- and 12- weeks post treatment.

Third objective: To explore whether the effects of active tDCS will augment the effects of rehabilitation therapy in treating individuals with CGH.

METHODS

This study will be a double-blind, sham-controlled, concealed allocation, randomized, clinical trial.

Clinical Assessments: Demographic information will be collected two weeks prior to starting the study including age, sex, education, headache history, concussion history, past medical history, medication use, and family medical history. Baseline questionnaires will be completed including 2-weeks of Headache Diaries Headache Impact Test - 6 (HIT-6), Rivermead PPCS questionnaire (RPQ), Headache Disability Index (HDI), European Quality of Life Five Dimension (EQ-5D), patient health questionnaire-9 (PHQ-9), generalized anxiety disorder scale-7 (GADS-7), Patient Reported Outcomes Measurement Information System Pain Interference Sub-scale (PROMIS-PI), the Pain Catastrophizing Scale (PCS), and the Numeric Pain Rating Scale (NPRS). Furthermore the following baseline neck mobility assessments will be used: the Craniocervical Flexion Test (CCFT), the Cervical Extensor Endurance Test (CEET), the Dynamometry Neck-Strength Assessment (DNSA), a range of cervical motion assessment (ROM), and a manual examination of the cervical joints (MECJ). Patients will keep a two-week baseline headache diary before treatment, 2 weeks during treatment, 2 weeks following tDCS, and for 2 weeks before the 6 and 12 week follow up assessments (total of 8 weeks). Patients will be reassessed at the completion of their tDCS treatment, and at 6- and 12-weeks post-treatment. The assessments administered at each follow up are: 2-week Headache Diaries, RPQ, HIT-6, HDI, EQ-5D, PHQ-9, GAD-7, NPRS, PCS, PROMIS-PI, CCFT, CEET, DNSA, ROM, and MECJ.

tDCS Protocol: Patients will engage in a six-week treatment protocol with 3 sessions per week (18 treatments). This was chosen to give participants at least a day between each session in order to minimize discomfort and because the number of sessions is consistent with previous migraine literature. The primary motor cortex (M1) will be the treatment target given previous literature highlighting reduced pain sensitivity and improved motor learning outcomes following tDCS stimulation of this region. M1 will be found through measurements of the head; more specifically the point halfway between the nasion and inion as well as halfway between the left and right tragus will be found, from here we will move down 20% of the distance between the left and right tragus while staying on the line between tragi. The anode will be placed over the M1 while the cathode will be placed over the super orbital region; each electrode will be held in place with a strap and will make as much contact with the skin as possible. tDCS will be delivered via two 35cm2 surface sponge electrodes at an intensity of 2mA in the active group and 0mA in the sham group. There will be a 30 second fade in and fade out period before and after stimulation with 20 minutes of active stimulation. In the sham condition, participants will only experience the 30 second fade in period and then the stimulator will be turned off. Previous sham studies have demonstrated the efficacy of this blinding method.

Physiotherapy Protocol: Participants will engage in a six-week physiotherapy program which will occur immediately following each tDCS session. The exercises to be used focus on head and back strength and motor control and were assembled by a licensed physiotherapist based on previous physiotherapy protocols for treating CGH. The exercises are performed at a level that is pain-free and are progressed when goals are reached (approximately every 2 weeks). Participants will also be expected to increase daily physical activity levels to 30 minutes per day for at least 5 days a week as a part of the physiotherapy program. This will be tracked using an exercise diary to be completed by participants each day.

Statistical Analysis: Summary statistics will be done and reported so that feasibility and safety can be assessed and future studies can use the results presented for power calculations.

Eligibility criteria: Inclusion Criteria:

* Diagnosed with cervicogenic headaches based on International Headache Society Guidelines lasting greater than 12 weeks
* The International Headache Society Guidelines are as follows: A) Presence of a headache fulfilling criterion C; B) Clinical and/or imaging evidence of a disorder or lesion within the cervical spine or soft tissues of the neck, known to be able to cause headache; C) Evidence of causation demonstrated by at least two of the following: (a) Headache has developed in temporal relation to the onset of the cervical disorder or appearance of the lesion; (b) Headache has significantly improved or resolved in parallel with improvement in or resolution of the cervical disorder or lesion; (c) Cervical range of motion is reduced and headache is made significantly worse by provocative maneuvers; (d) Headache is abolished following diagnostic blockade of a cervical structure or its nerve supply.
* Average pain score ≥ 4/10 and Neck Disability score ≥ 28/50

Exclusion Criteria:

* Known cervical spine pathology (such as tumours or fractures)
* Nerve root pain/sensory loss
* Muscular or joint inflammatory conditions
* Neurological or psychiatric conditions
* Undergone recent surgery (within prior year)
* Have contraindications to tDCS (metal or electronic implants in the brain/skull; metal or electronic implants in other sites on the body; surgical procedures involving the head or spinal cord; skin problems such as dermatitis, psoriasis or eczema; epilepsy or a previous convulsion/seizure; fainting spells or syncope; pregnancy or any chance of pregnancy; previous electrical or magnetic stimulation)

Primary outcomes:
measure: Feasibility of tDCS through recruitment rate, retention rate in the study, and adherence rates to both tDCS and exercise therapy.
timeFrame: To be assessed throughout the 6 weeks of treatment and at post-treatment follow-up.
measure: Safety of tDCS through adverse events and transient changes in adverse effects within each tDCS session.
timeFrame: To be assessed throughout the 6 weeks of treatment up to the post-treatment follow-up.
measure: Craniocervical Flexion Test (CCFT)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
Secondary outcomes:
measure: European Quality of Life Five Dimension (EQ-5D)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Headache Impact Test 6 (HIT-6)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Headache Disability Index (HDI)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Pain Catastrophizing Scale (PCS)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: PROMIS Pain Interference Scale
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Cervical Extensor Endurance Test (CEET)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Dynamometry Neck-Strength Assessment (DNSA)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Patient health questionnaire 9 (PHQ-9)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Generalized anxiety disorder scale 7 (GADS-7)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Cervical Flexor Endurance Test (CFET)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Numeric Pain Rating Scale (NPRS)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Range of Motion of Cervical Joints (ROM)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
measure: Manual Examination of Cervical Joints (MECJ)
timeFrame: To be assessed at baseline, immediately after treatment and at 6 and 12 weeks post treatment.
Other outcomes:
measure: Headache Diary
timeFrame: To be completed 2 weeks prior to treatment, 2 weeks after treatment, 2 weeks prior to 6 week assessment, and 2 weeks prior to 12 week assessment for a total of 8 weeks.
measure: Exercise diary
timeFrame: To be completed each day for the duration of treatment (6 weeks).
Locations:
city: Calgary
country: Canada
facility: University of Calgary
state: Alberta
Study officials:
affiliation: University of Calgary
name: Chantel T Debert, MD MSc FRCPC CSCN
role: PRINCIPAL_INVESTIGATOR
References:
citation: Langer L, Levy C, Bayley M. Increasing Incidence of Concussion: True Epidemic or Better Recognition? J Head Trauma Rehabil. 2020 Jan/Feb;35(1):E60-E66. doi: 10.1097/HTR.0000000000000503.
citation: Barnsley L, Lord S, Bogduk N. Whiplash injury. Pain. 1994 Sep;58(3):283-307. doi: 10.1016/0304-3959(94)90123-6. No abstract available.
citation: Sjaastad O, Fredriksen TA, Batnes J, Petersen HC, Bakketeig LS. Whiplash in individuals with known pre-accident, clinical neck status. J Headache Pain. 2006 Feb;7(1):9-20. doi: 10.1007/s10194-006-0270-x. Epub 2006 Feb 20.
citation: Lord SM, Barnsley L, Wallis BJ, Bogduk N. Third occipital nerve headache: a prevalence study. J Neurol Neurosurg Psychiatry. 1994 Oct;57(10):1187-90. doi: 10.1136/jnnp.57.10.1187.
citation: Lindblom U, Verrillo RT. Sensory functions in chronic neuralgia. J Neurol Neurosurg Psychiatry. 1979 May;42(5):422-35. doi: 10.1136/jnnp.42.5.422.
citation: Becser N, Sand T, Pareja JA, Zwart JA. Thermal sensitivity in unilateral headaches. Cephalalgia. 1998 Dec;18(10):675-83; discussion 657. doi: 10.1046/j.1468-2982.1998.1810675.x.
citation: Bogduk N, Govind J. Cervicogenic headache: an assessment of the evidence on clinical diagnosis, invasive tests, and treatment. Lancet Neurol. 2009 Oct;8(10):959-68. doi: 10.1016/S1474-4422(09)70209-1.
citation: Bogduk N. Cervicogenic headache: anatomic basis and pathophysiologic mechanisms. Curr Pain Headache Rep. 2001 Aug;5(4):382-6. doi: 10.1007/s11916-001-0029-7.
citation: Dumas JP, Arsenault AB, Boudreau G, Magnoux E, Lepage Y, Bellavance A, Loisel P. Physical impairments in cervicogenic headache: traumatic vs. nontraumatic onset. Cephalalgia. 2001 Nov;21(9):884-93. doi: 10.1046/j.1468-2982.2001.00264.x.
citation: Manchikanti L, Pampati V, Kaye AD, Hirsch JA. Cost Utility Analysis of Cervical Therapeutic Medial Branch Blocks in Managing Chronic Neck Pain. Int J Med Sci. 2017 Oct 15;14(13):1307-1316. doi: 10.7150/ijms.20755. eCollection 2017.
citation: Frazer A, Williams J, Spittles M, Rantalainen T, Kidgell D. Anodal transcranial direct current stimulation of the motor cortex increases cortical voluntary activation and neural plasticity. Muscle Nerve. 2016 Nov;54(5):903-913. doi: 10.1002/mus.25143. Epub 2016 May 20.
citation: Rroji O, van Kuyck K, Nuttin B, Wenderoth N. Anodal tDCS over the Primary Motor Cortex Facilitates Long-Term Memory Formation Reflecting Use-Dependent Plasticity. PLoS One. 2015 May 21;10(5):e0127270. doi: 10.1371/journal.pone.0127270. eCollection 2015.
citation: Zaninotto AL, El-Hagrassy MM, Green JR, Babo M, Paglioni VM, Benute GG, Paiva WS. Transcranial direct current stimulation (tDCS) effects on traumatic brain injury (TBI) recovery: A systematic review. Dement Neuropsychol. 2019 Apr-Jun;13(2):172-179. doi: 10.1590/1980-57642018dn13-020005.
citation: Wessel MJ, Zimerman M, Hummel FC. Non-invasive brain stimulation: an interventional tool for enhancing behavioral training after stroke. Front Hum Neurosci. 2015 May 15;9:265. doi: 10.3389/fnhum.2015.00265. eCollection 2015.
citation: O'Connell NE, Marston L, Spencer S, DeSouza LH, Wand BM. Non-invasive brain stimulation techniques for chronic pain. Cochrane Database Syst Rev. 2018 Apr 13;4(4):CD008208. doi: 10.1002/14651858.CD008208.pub5.
citation: Begemann MJ, Brand BA, Curcic-Blake B, Aleman A, Sommer IE. Efficacy of non-invasive brain stimulation on cognitive functioning in brain disorders: a meta-analysis. Psychol Med. 2020 Nov;50(15):2465-2486. doi: 10.1017/S0033291720003670. Epub 2020 Oct 19.
citation: Stilling JM, Monchi O, Amoozegar F, Debert CT. Transcranial Magnetic and Direct Current Stimulation (TMS/tDCS) for the Treatment of Headache: A Systematic Review. Headache. 2019 Mar;59(3):339-357. doi: 10.1111/head.13479. Epub 2019 Jan 23.
citation: Rahimi MD, Fadardi JS, Saeidi M, Bigdeli I, Kashiri R. Effectiveness of cathodal tDCS of the primary motor or sensory cortex in migraine: A randomized controlled trial. Brain Stimul. 2020 May-Jun;13(3):675-682. doi: 10.1016/j.brs.2020.02.012. Epub 2020 Feb 14.
citation: Andrade SM, de Brito Aranha REL, de Oliveira EA, de Mendonca CTPL, Martins WKN, Alves NT, Fernandez-Calvo B. Transcranial direct current stimulation over the primary motor vs prefrontal cortex in refractory chronic migraine: A pilot randomized controlled trial. J Neurol Sci. 2017 Jul 15;378:225-232. doi: 10.1016/j.jns.2017.05.007. Epub 2017 May 3.
citation: Dunning JR, Butts R, Mourad F, Young I, Fernandez-de-Las Penas C, Hagins M, Stanislawski T, Donley J, Buck D, Hooks TR, Cleland JA. Upper cervical and upper thoracic manipulation versus mobilization and exercise in patients with cervicogenic headache: a multi-center randomized clinical trial. BMC Musculoskelet Disord. 2016 Feb 6;17:64. doi: 10.1186/s12891-016-0912-3.
citation: Fernandez M, Moore C, Tan J, Lian D, Nguyen J, Bacon A, Christie B, Shen I, Waldie T, Simonet D, Bussieres A. Spinal manipulation for the management of cervicogenic headache: A systematic review and meta-analysis. Eur J Pain. 2020 Oct;24(9):1687-1702. doi: 10.1002/ejp.1632. Epub 2020 Jul 20.
citation: Chaibi A, Russell MB. Manual therapies for cervicogenic headache: a systematic review. J Headache Pain. 2012 Jul;13(5):351-9. doi: 10.1007/s10194-012-0436-7. Epub 2012 Mar 30.
citation: Debarnot U, Neveu R, Samaha Y, Saruco E, Macintyre T, Guillot A. Acquisition and consolidation of implicit motor learning with physical and mental practice across multiple days of anodal tDCS. Neurobiol Learn Mem. 2019 Oct;164:107062. doi: 10.1016/j.nlm.2019.107062. Epub 2019 Aug 1.
citation: Lefebvre S, Laloux P, Peeters A, Desfontaines P, Jamart J, Vandermeeren Y. Dual-tDCS Enhances Online Motor Skill Learning and Long-Term Retention in Chronic Stroke Patients. Front Hum Neurosci. 2013 Jan 9;6:343. doi: 10.3389/fnhum.2012.00343. eCollection 2012.
citation: Hatem SM, Saussez G, Della Faille M, Prist V, Zhang X, Dispa D, Bleyenheuft Y. Rehabilitation of Motor Function after Stroke: A Multiple Systematic Review Focused on Techniques to Stimulate Upper Extremity Recovery. Front Hum Neurosci. 2016 Sep 13;10:442. doi: 10.3389/fnhum.2016.00442. eCollection 2016.
citation: Antal A, Alekseichuk I, Bikson M, Brockmoller J, Brunoni AR, Chen R, Cohen LG, Dowthwaite G, Ellrich J, Floel A, Fregni F, George MS, Hamilton R, Haueisen J, Herrmann CS, Hummel FC, Lefaucheur JP, Liebetanz D, Loo CK, McCaig CD, Miniussi C, Miranda PC, Moliadze V, Nitsche MA, Nowak R, Padberg F, Pascual-Leone A, Poppendieck W, Priori A, Rossi S, Rossini PM, Rothwell J, Rueger MA, Ruffini G, Schellhorn K, Siebner HR, Ugawa Y, Wexler A, Ziemann U, Hallett M, Paulus W. Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. Clin Neurophysiol. 2017 Sep;128(9):1774-1809. doi: 10.1016/j.clinph.2017.06.001. Epub 2017 Jun 19.
citation: Cote P, Yu H, Shearer HM, Randhawa K, Wong JJ, Mior S, Ameis A, Carroll LJ, Nordin M, Varatharajan S, Sutton D, Southerst D, Jacobs C, Stupar M, Taylor-Vaisey A, Gross DP, Brison RJ, Paulden M, Ammendolia C, Cassidy JD, Loisel P, Marshall S, Bohay RN, Stapleton J, Lacerte M. Non-pharmacological management of persistent headaches associated with neck pain: A clinical practice guideline from the Ontario protocol for traffic injury management (OPTIMa) collaboration. Eur J Pain. 2019 Jul;23(6):1051-1070. doi: 10.1002/ejp.1374. Epub 2019 Feb 28.
citation: Rani M, Kaur J. Effectiveness of different physiotherapy interventions in the management of cervicogenic headache: a pilot randomized controlled trial. J Man Manip Ther. 2022 Apr;30(2):96-104. doi: 10.1080/10669817.2021.1962687. Epub 2021 Aug 10.
citation: Houts CR, McGinley JS, Wirth RJ, Cady R, Lipton RB. Reliability and validity of the 6-item Headache Impact Test in chronic migraine from the PROMISE-2 study. Qual Life Res. 2021 Mar;30(3):931-943. doi: 10.1007/s11136-020-02668-2. Epub 2020 Oct 20.
citation: Eyres S, Carey A, Gilworth G, Neumann V, Tennant A. Construct validity and reliability of the Rivermead Post-Concussion Symptoms Questionnaire. Clin Rehabil. 2005 Dec;19(8):878-87. doi: 10.1191/0269215505cr905oa.
citation: Jabbari S, Salahzadeh Z, Sarbakhsh P, Rezaei M, Farhoudi M, Ghodrati M. Validity and Reliability of Persian Version of Henry Ford Hospital Headache Disability Inventory Questionnaire. Arch Iran Med. 2021 Oct 1;24(10):752-758. doi: 10.34172/aim.2021.111.
citation: Robinson-Papp J, George MC, Wongmek A, Nmashie A, Merlin JS, Ali Y, Epstein L, Green M, Serban S, Sheth P, Simpson DM. The Quantitative Analgesic Questionnaire: A Tool to Capture Patient-Reported Chronic Pain Medication Use. J Pain Symptom Manage. 2015 Sep;50(3):381-6. doi: 10.1016/j.jpainsymman.2015.03.013. Epub 2015 Apr 23.
citation: Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001 Sep;16(9):606-13. doi: 10.1046/j.1525-1497.2001.016009606.x.
citation: Lowe B, Decker O, Muller S, Brahler E, Schellberg D, Herzog W, Herzberg PY. Validation and standardization of the Generalized Anxiety Disorder Screener (GAD-7) in the general population. Med Care. 2008 Mar;46(3):266-74. doi: 10.1097/MLR.0b013e318160d093.
citation: Young IA PT, DSc, Dunning J PT, DPT, Butts R PT, PhD, Mourad F PT, DPT, Cleland JA PT, PhD. Reliability, construct validity, and responsiveness of the neck disability index and numeric pain rating scale in patients with mechanical neck pain without upper extremity symptoms. Physiother Theory Pract. 2019 Dec;35(12):1328-1335. doi: 10.1080/09593985.2018.1471763. Epub 2018 Jun 1.
citation: James G, Doe T. The craniocervical flexion test: intra-tester reliability in asymptomatic subjects. Physiother Res Int. 2010 Sep;15(3):144-9. doi: 10.1002/pri.456.
citation: Sebastian D, Chovvath R, Malladi R. Cervical extensor endurance test: a reliability study. J Bodyw Mov Ther. 2015 Apr;19(2):213-6. doi: 10.1016/j.jbmt.2014.04.014. Epub 2014 Apr 18.
citation: Versteegh T, Beaudet D, Greenbaum M, Hellyer L, Tritton A, Walton D. Evaluating the reliability of a novel neck-strength assessment protocol for healthy adults using self-generated resistance with a hand-held dynamometer. Physiother Can. 2015 Winter;67(1):58-64. doi: 10.3138/ptc.2013-66.
citation: Cleland BT, Galick M, Huckstep A, Lenhart L, Madhavan S. Feasibility and Safety of Transcranial Direct Current Stimulation in an Outpatient Rehabilitation Setting After Stroke. Brain Sci. 2020 Oct 9;10(10):719. doi: 10.3390/brainsci10100719.
citation: Osman A, Barrios FX, Kopper BA, Hauptmann W, Jones J, O'Neill E. Factor structure, reliability, and validity of the Pain Catastrophizing Scale. J Behav Med. 1997 Dec;20(6):589-605. doi: 10.1023/a:1025570508954.
citation: Stark RG, Reitmeir P, Leidl R, Konig HH. Validity, reliability, and responsiveness of the EQ-5D in inflammatory bowel disease in Germany. Inflamm Bowel Dis. 2010 Jan;16(1):42-51. doi: 10.1002/ibd.20989.
citation: Harris KD, Heer DM, Roy TC, Santos DM, Whitman JM, Wainner RS. Reliability of a measurement of neck flexor muscle endurance. Phys Ther. 2005 Dec;85(12):1349-55.