Table 3.

Summary of studies reporting SNIP outcomes

Author year	Data source, territory, population	N	Age	SNIP outcome data reported
Chabanon 2018 [44]	NatHis-SMA	81	Adults and children	SNIP % predicted values, median (IQR)
	Belgium, France, and Germany			•Type 2 SMA, non-sitter (n = 15): 35 (22–64)
	Types 2 and 3 SMA			•Type 2 SMA, sitter (n = 9): 33 (26–56)
				•Type 3 SMA, non-ambulant (n = 9): 56 (27–99)
				•Type 3 SMA, ambulant (n = 10): 45 (35–76)
				•Overall (n = 43): 39 (28–60)
				Patients > 6 years of age performed SNIP assessments in the sitting position which were captured with the MicroRPM device; the best results of three measurements were selected for analysis
Kapur 2019 [42]	Children attending the Children’s Health Queensland, Brisbane, Australia	25	Children	SNIP median Z score (IQR) (n = 14) from a cross-sectional study
	Types 1–3 SMA			•Type 2 SMA: –2.53 (2.61)
				•Type 3 SMA: –1.32 (2.47)
				•All patients: –2.06 (2.87)
				Median Z scores were lower in patients who needed NIV (results displayed graphically); p = 0.25
				Children who refused to perform a respiratory test were not forced. Standard testing methods were used
Veldhoen 2022 [7]	Patients enrolled in this study were participating in a prospective, population-based prevalence cohort study on SMA in the Netherlands (Wadman 2017, 2018, 2020)	57	Adults and children	SNIP, median (cmH2O):
	Types 1–3 SMA			•Type 1c SMA: 33
				•Type 2a SMA: 44
				•Type 2b SMA: 59
				•Type 3a SMA: 58
				•Type 3b SMA: 55
				Results also reported graphically in box plots
				There was a significant trend of increasing SNIP with less severe SMA types (p = 0.0053)
				All SNIP outcomes were below 75 cmH2O, which is considered the lower limit of normal

Abbreviations: IQR = interquartile range; NatHis = natural history; NIV = non-invasive ventilation; SMA = spinal muscular atrophy; SNIP = sniff nasal inspiratory pressure.