The Influence of Sour Taste on Dysphagia in Brain Injury: Blind Study

OBJECTIVE: To verify the influence of sour taste on swallowing and the presence of reflex cough when sour material was swallowed in patients with dysphagia secondary to brain injury. METHOD: Fifty dysphagic brain injury patients who underwent videofluoroscopic swallowing study (VFSS) were recruited. The patients who had shown severe aspiration at 2 ml of liquid were excluded. The dysphagic patients were given 5 ml each of a sour tasting liquid (SOUR) and a thin liquid barium (LIQUID) in random order. An expert analyzed the result of VFSS by reviewing recorded videotapes. Analysis components consisted of the Penetration-Aspiration-Scale (PAS) score, oral transit time (OTT), pharyngeal transit time (PTT), pharyngeal delay time (PDT) and the reflex cough presence. RESULTS: The PAS score for SOUR was significantly lower than the one for LIQUID (p=0.03). The mean OTT for SOUR was significantly shortened compared to that for LIQUID (p=0.03). The mean PTT and PDT were also shortened in SOUR, although the differences were not statistically significant (p=0.26 and p=0.32, respectively). There was no significant difference between SOUR and LIQUID regarding the presence of reflex cough (p=1.00). CONCLUSION: The sour taste could enhance sensorimotor feedback in the oropharynx, thus lowering the chances of penetration-aspiration caused by shortening of the oropharyngeal passage times. There was no significant difference in the presence of reflex cough produced between LIQUID and SOUR.