Table 2.

Summary of methods

Ref.	Study design	Participants	Type of seat	Tilt angles	Timing and order of tilt	Comments	Evidence level
(a) Studies involving posterior tilt
3	Case study	1, 9-year old with CP	Wheelchair including head rest, lateral and anterior trunk support, foot support. 90° seat-to-back angle	0°, 15° and 30° posterior tilt	10 sessions with 20 min at each tilt angle in variable order		5
4	1: Cross-over study	10 adults with MS	Same manual wheelchair	0° and 25° posterior tilt	15 min upright then 15 min tilted		4
	2: RCT	20 adults with MS		0° and 25° or 45° posterior tilt	Upright then tilted. No acclimatization period	Subjects randomly assigned to 25° or 45° tilt angle	2
5, 20	Cross-over study	12 adults with complete SCI	Reclining/tilting wheelchair with seat cushion, arm and foot rests. 100° seat-to-back angle	0°, 10° and 20° posterior tilt	Set order for testing positions. 15 min acclimatization in each position	6 other positions tested within session	4
6	Cross-over study	2 adults with C5 quadriplegia	Subjects’ own wheelchairs with 100° seat-to-back angle	0°, 35° and 45° posterior tilt	Single session with set order for positions: 0°, 35°, 45° and 0° (repeated)	2 other positions tested. Repeated on 3 seat cushions	5
7	Cross-over study	15 children (7–18 years) with myelo- meningocele	Chair with back and head rest, foam cushion on base, 90° seat-to-back angle	0° and 25° posterior tilt	Randomized order for positions with each position repeated twice. 30 seconds data collection in each position	3 other positions also tested	2
15	Cross-over study	16 adults, SCI, motor complete tetraplegia	Subjects’ own powered wheelchairs. 95° median seat-to-back angle	5° median and 45° posterior tilt	Upright for 1 min, then tilted for 1 min	Repeated on 2 seat cushions. Inter-subject position variations	4
16	Cross-over study	18 adults with complete SCI (C5–L2)	Powered wheelchair with 90° seat-to-back angle	5°, 15° and 25° posterior tilt	3 sessions with all conditions tested in random order in session. 15 seconds in each condition	Testing repeated at 3 cushion inflation pressures	2
17	Cross-over study	11 children (4–8 years) with spastic CP	90° seat-to-back angle, head rest, lateral trunk supports, adductor wedge; foot rest	0° and 150 posterior tilt	Single session with random order to positions. 3 min acclimatization in each position	5 other positions also tested	2
19	Cross-over study	20 adults with complete thoracic SCI	Chair with back and foot rests, 100° seat-to-back angle	0°, 7° and 12° posterior tilt	Single session with random tilt order. Each position repeated twice	1 other position tested. Subjects undertook reaching task during measurement	2
21	Cross-over study	14 adults, C6-T10 motor complete SCI	E&J Premier (upright) and Quickie Breezy 500 (4° posterior tilt) wheelchairs. 90° seat-to-back angle	0° and 4° posterior tilt	Single session, with random order for testing chairs. Time in chairs not specified	Additional differences between wheelchairs. Chair with acute seat-to-back angle also tested	4
25	Cross-over study	10 adults with SCI	Subjects’ own wheelchair with seat cushion	0°, 35° and 65° posterior tilt	Single session with set order for positions: 0°, 35°, 65°	Another position also tested	4
27	Cross-over study	12 children (6–18 years) with CP (spastic diplegia)	As in ref. 18. Hip abductor also included	0° and 30° posterior tilt	Single session with random tilt order. 5 min acclimatization in each position		2
29	Cross-over study	6 children with spastic CP, mean age 6 years	Upholstered seat base, foot rests. No back rest nor arm rests	0° and 10° anterior tilt	2–3 min acclimatization, 5 min upright 5 min tilted. Repeated at 3 sessions	Subjects independent sitters and ambulatory	4
(b) Studies involving anterior and posterior tilt
22	Case series	23 children with CP (2–16 years)	Range of seats, providing foot, pelvic and trunk support. Seat-to-back angle ranging from 9° to 130°	0–30° posterior (mean 8°) and 0–15° anterior tilt (mean 8°)	Single session with random order to positions and 5 min in each position	Tilt angles varied between subjects. Seats also varied between subjects and tilts. Repeated with table and abductor	5
24	Cross-over study.	10 children with spastic CP	90° seat-to-back angle, head rest, lateral trunk supports, chest panel, foot rest	0°, 15°, 30° posterior and 15° anterior tilt	Random order to tilt positions, then repeated in reverse order. 5 min acclimatization in each position	3 children with athetoid CP also measured (analysed separately)	2
28	Cross-over study	10 children with spastic CP (4–15 years)	Chair with back rest and foot support. 90° seat-to-back angle changed to 95° for anterior tilt	0°, 5° posterior and 5° anterior tilt	3 sessions with one randomly selected tilt angle per session	Measurements during ‘quiet sitting’ and during upper extremity activity	2
(c) Studies involving anterior tilt
18	Cross-over study	15 children (2–6 years) with developmental delay and/or CP	Adjustable bench with non-skid surface	0°, 20° and 30° anterior tilt	Single session of 30 min. Random order for testing positions with 1 min acclimatization in each position	2 other positions/seats measured. Limited control over bench postures	4
26	Cross-over study	20 adults with complete thoracic SCI	Chair with flat/ramped seat base, foot support, and support behind trunk.	0° and 10° anterior tilt	Single session. Upright then tilted	Base only tilted. Subjects undertook reaching task	4
23	Cross-over study	14 children with CP (5–11 years)	Upholstered seat base, foot rests. No back rest nor arm rests	0°, 10° and 15° anterior tilt	Four 20-minute sessions each at 2 tilt angles (0–10°, 10–0°, 0–15°, 15–0°)	Subjects independent sitters and ambulatory	2

CP, cerebral palsy; MS, multiple sclerosis; SCI, spinal cord injury.