The technology of tongue and hard palate contact detection: a review

Table 1 Timeline of modification and development of EPG

Year	Modification and development of EPG	Refs
1974–1978	Europe, EPG developed at Reading University	[14, 15]
1979	Japan, the Rion Co Ltd patented a flexible insulative circuit board and improvement in the fabrication method	[16]
1978	US, Development of Palatometer by Fletcher	[17]
1981	Japan, the Rion Co Ltd patented EPG by introducing a single signal-receiving electrode by a single detector	[12]
1982	The Rion Co Ltd again patented their EPG by improving transmission and receiver from the EPG to the display device	[13]
1989	T-shape cut-out by Hardcastle et al. with flexible circuit design	[4]
1991	The Reading palate improvement in hardware and software design	[18]
2005	Fletcher produced patented three-lobed structure	[19]
2007	Wrench developed and patented articulate-style palate	[3, 20]
2014	Ghovanloo et al. patented wireless Real-time Tongue Tracking	[21]
2018	Development on SmartPalate	[11]

ISSN: 1475-925X