THE EFFECTS OF BLINDFOLDING AND BLINDNESS ON THE UNSTIMULATED AND CHEWING-GUM-STIMULATED FLOW-RATES OF WHOLE SALIVA

In the early 1970s, Shannon and his colleagues reported that blindfold ing caused a reduction in the flow rate of unstimulated and stimulated parotid and submandibular saliva. A study in three parts was now made to investigate the effects of blindfolding or blindness on the flow r ate of whole saliva. For the first study, unstimulated whole saliva (U WS) was collected for 5 min from 34 individuals and then eight samples of chewing-gum-stimulated whole saliva (SWS) over a 20-min period. Th is was carried out on four separate occasions, on two of which, in ran dom order, the individuals collected the saliva immediately after bein g blindfolded. For the second study, 33 of the individuals repeated th e saliva collection protocol on two occasions, with and without blindf olding, but with an accommodation period of 20 min after blindfolding before beginning collection of UWS and with only three samples of SWS being collected over a 4-min period. The flow rate of UWS while blindf olded was significantly (p < 0.0001) reduced (to 64 and 71% of the flo w rate while sighted, in the first and second studies, respectively), as was the flow rate of SWS (to 81-86%, p < 0.0001; and 91-95%, p = 0. 0014, respectively). For the third study, UWS and SWS were collected f rom 24 blind individuals, ranging in age from 13-73 years, and from 24 age- and gender-matched controls. The flow rates of UWS and SWS were not significantly different in the blind participants and controls. DM FT values were 11.1 +/- 1.4 and 12.3 +/- 1.5 (mean +/- SE) in the blin d and the controls, respectively, and these values were not significan tly different. Thus this study provides no evidence that blind people have lower salivary flow rates or are more susceptible to dental carie s than are people with normal sight.