Thicker is better? Impact of food consistencies on aspiration detection using IDDSI levels.

Background/purpose: Water is the most commonly, and often the only tested material in swallow screening. Our objective is to assess the impact of food consistencies on the reliability of trial swallows in predicting aspiration in dysphagic patients, utilizing the International Dysphagia Diet Standardisation Initiative (IDDSI) levels.

Methods: All trial swallows were evaluated using 5 ml of standardized test food with IDDSI levels of 0, 2, 4, 5. The flexible endoscopic evaluation of swallowing was used as the basis for comparison. The sensitivity, specificity, and predictive values of commonly used direct clinical signs for the detection of aspiration were analyzed, including cough with swallow (choking) and post-swallow voice change (wet voice).

Results: IDDSI 2 test food demonstrated the highest accuracy for detecting aspiration when using both clinical signs of cough (91%) and wet voice (83%). Despite reduced risk of aspiration, the percentage of silent aspiration among aspirators was significantly higher when tested with higher IDDSI levels of test food.

Conclusion: The diagnostic accuracy of commonly-used clinical signs for the indication of aspiration is significantly affected by food consistency. Test foods with varying consistencies, particularly those at IDDSI level 2, should be considered during clinical swallow examinations, especially for screening purposes.