Tongue-palate pressure is a parameter of considerable interest in the field of dysphagia. Maximum isometric tongue-palate pressures (MIPs) decline in healthy aging and in dysphagia. Functional reserve (FR) is the difference between MIPs and swallowing pressures. Reduced FR is thought to constitute a risk for developing functional swallowing impairments. We compare different approaches for calculating FR and recommend an optimal approach. Tongue-palate pressure data were collected from 78 healthy adults ( ; ) during anterior and posterior MIPs, regular (RESS) and effortful (ESS) saliva swallows, and water swallows (4 repetitions per task). Six different measures of reserve were calculated using maximum anterior MIPs or ESS pressures at the top, and mean or maximum RESS or water swallow pressures at the bottom of the range. Correlations with age and MIPs were explored to confirm suitability for measuring FR. The impact of normalization to maximum MIP range was explored. We conclude that an optimal measure of FR involves the comparison of maximum MIP with mean saliva swallowing pressures. This parameter declines with age, but when normalized to an individual’s MIP range, the relationship is no longer evident. This suggests that FR does not necessarily decline in healthy aging. 1. Introduction The ability to generate tongue-palate pressure has emerged as a measure of considerable clinical and research interest in the field of dysphagia over the past two decades. Key to this interest is that tongue strength, measured during maximum isometric tongue-palate pressure tasks (MIPs), appears to decline in healthy aging [1–6]. This has been argued to resemble sarcopenia, a degenerative loss of skeletal muscle mass and strength seen in aging in the limb musculature. Reduced tongue strength has also been observed in adults with dysphagia [7–10]. These observations have prompted research into exercise-based methods for tongue strengthening in the hope that greater tongue strength and endurance will lead to improved swallowing function [9, 11, 12]. Functional reserve is the term coined to describe the difference in pressures generated in maximum isometric pressure (MIP) tasks compared to swallowing tasks. Robbins and colleagues were the first to point out that swallowing pressures appear to be preserved in healthy older adults, even in the presence of reduced MIPs. Reductions in functional reserve, due to reductions in MIPs, were argued to have important clinical implications and to place a person at greater risk of developing functional swallowing impairments,
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