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.