TABLE 2.

Characteristics of articles retrieved.

Level of Evidence (CEBM)	Experimental Design	Validity Score (PEDro Scale)	Author(s)
lb	RCT	6/10	Schillinger et al11
lb	RCT	7/10	Harén et al12
2b	Prospective randomized controlled clinical trial	6/10	Eisenhart et al2
4	Case study	N/A	Weiss4
4	Pilot study	N/A	Asplund13
4	Case study	N/A	Lancaster & Crow14
5	Animal model	N/A	Déry et al15
5	Animal model	N/A	Knott et al16
5	Animal model	N/A	Hodge et al17
	Oxford Center of Evidence-Based Medicine: Levels of Evidence9,10 1a: Systematic reviews of RCTs 1b: Individual RCTs 1c: All-or-none studies 2a: Systematic reviews of cohort studies 2b: Individual cohort studies or low quality RCTs (< 80% follow-up) 2c: Outcomes research 3a: Systematic reviews of case-control studies 3b: Individual case-control studies 4: Case series, poorly designed cohort or case-control studies 5: Animal and bench research