Thirty five studies fulfilled the review inclusion criteria, but only 11 (n=886) achieved a quality rating of sufficient and were included in the review.
Five studies assessed trial swallows using water and reported sensitivity that ranged from 27% to 85% and specificity that ranged from 50% to 88%. LR+ ranged from 2.1 to 3.6 and LR- ranged from 0.2 to 0.8.
Four studies evaluated trial swallows using substances with different viscosities. Sensitivity ranged from 41% to 100% and specificity ranged from 57% to 82%. LR+ ranged from 1.3 to 3.7 and LR- ranged from 0.0 to 0.8.
Three studies assessed oxygen desaturation (≥2%). Sensitivity ranged from 56% to 87% and specificity ranged from 39% to 97%. LR+ ranged from 1.4 to 18.9 and LR- ranged from 0.3 to 0.5.
Three studies assessed a combination of a swallow test and oxygen desaturation. Sensitivity ranged from 73% to 98% and specificity ranged from 63% to 76%. LR+ ranged from 2.5 and 3.3 and LR- ranged from 0.0 to 0.3.
Three studies assessed a range of clinical features that had low sensitivity, low specificity or both. LR+ ranged from 1.1 to 3.2 and LR- ranged from 0.1 to 1.0.
One study assessed a history of poor nutrition and reported LR+ of 2.1 and LR- of 0.7.
Three studies assessed a standardised form to record various clinical features. Sensitivity ranged from 58% to 93% and specificity ranged from 30% to 63%. LR+ ranged from 1.2 to 6.7 and LR- ranged from 0.1 to 0.7.