. Author manuscript; available in PMC: 2014 Aug 20.

Published in final edited form as: Laryngoscope. 2014 Apr 29;124(8):1862–1868. doi: 10.1002/lary.24539

TABLE III.

Threshold Volume to Elicit PGCR, PUCR, and RPS in Young and Elderly Subjects Using Slow and Rapid Pharyngeal Water Injections.

	Injection	Young, mL (mean ±SD)	Elderly, mL (mean ±SD)	P Value
PGCR	Slow	0.13 ±0.06	0.18 ±0.13	NS
	Rapid	0.07 ±0.03	0.08 ±0.03	NS
PUCR	Slow	0.20 ±0.08	0.20 ±0.13	NS
	Rapid	0.19 ±0.15	0.22 ±0.14	NS
RPS	Slow^*	0.59 ±0.27	0.63 ±0.47	NS
	Rapid	0.38 ±0.19	0.40 ±0.23	NS
HPSV		0.82 ±0.41	0.80 ±0.46	NS

By abolishing RPS with topical pharyngeal anesthesia, HPSV was measured.

During slow water perfusion, RPS was absent in five of 30 injections in the elderly subjects (excluded from analysis of threshold volume).

HPSV =hypopharyngeal safe volume; NS =not significant; PGCR = pharyngoglottal closure reflex; PUCR =pharyngo-UES contractile reflex; RPS =reflexive pharyngeal swallow; SD =standard deviation.