Table 6 Cross-tabulation of each test measuring global inspiratory, diaphragm and expiratory strength

	Sniff Pnasal		Total
	Normal	Low	Total
Group A: Inspiratory muscle tests
Pimax
Normal	92	17	109
Low	14	59	73
Total	106	76	182
	Sniff Poes
	Normal	Low	Total
Pimax
Normal	94	15	109
Low	19	54	73
Total	113	69	182
	Sniff Poes
	Normal	Low	Total
Sniff Pnasal
Normal	101	5	106
Low	12	64	76
Total	113	69	182
Group B: Diaphragm tests
	Twitch Pdi
	Normal	Low	Total
Sniff Pdi
Normal	52	32	84
Low	34	146	180
Total	86	178	264
Group C: Expiratory muscle tests
	Pemax
	Normal	Low	Total
Cough Pgas
Normal	31	7	38
Low	6	16	22
Total	37	23	60
	Twitch T10
	Normal	Low	Total
Pemax
Normal	30	7	37
Low	13	10	23
Total	43	17	60
	Twitch T10
	Normal	Low	Total
Cough Pgas
Normal	36	2	38
Low	7	15	22
Total	43	17	60

Pimax, maximum inspiratory pressure; Pnasal, nasal pressure; Poes, oesophageal pressure; Pdi, transdiaphragmatic pressure; Pemax, maximum expiratory pressure; Pgas, gastric pressure.