Table 3.

Summary of studies of neurodegenerative nonverbal oral apraxia (NVOA).

Reference(s)	Key findings re NVOA
Botha (2014)	• Present in 59% of 30 patients with PPAOS or AOS > aphasia • Present in 78% of 9 patients with nfPPA (with no or less prominent AOS) • Associated with bilateral atrophy of SMA and prefrontal cortex anterior to premotor area
(Josephs, Duffy, Strand, Machulda, Senjem, Gunter, et al., 2014; Josephs et al., 2013; Josephs et al., 2012; Josephs, Petersen, et al., 2006; Utianski, Duffy, Clark, Strand, Botha, et al., 2018).	• Prevalence range from 33% to 62% in other studies of PPAOS by Mayo Clinic research group; patient numbers ranging from 7 to 21 • Prevalence does not seem to differ between PPAOS subtypes
Ogar et al. (2007)	• Present in 61% of 18 patients with nfPPA (all with AOS)
(Gallassi et al., 2011; Laganaro et al., 2012; Ricci et al., 2008)	• Frequent co-occurrence of PPAOS and NVOA in case studies
Duffy, Peach, Strand (2007)	• Present in 71% of 7 patients with ALS and AOS+PAA on initial examination; present in all 7 patients on subsequent examination
(Josephs, Duffy, Strand, Machulda, Senjem, Gunter, et al., 2014; Santos-Santos et al., 2016; Utianski, Duffy, Clark, Strand, Boland, et al., 2018)	• Prevalence of NVOA increases over time in PPAOS