Analysis of voice change during cellular phone use: a blinded controlled study

It is a growing belief that cellular phone use may be hazardous to the voice. This study aims to assess voice production in different conversational scenarios to identify any changes in vocal production that may be specific to cellular phone use. Twenty healthy participants were randomized to seven conversational scenarios: quiet conditions face to face; quiet conditions over a landline; quiet conditions using a cellular phone (QCP); quiet conditions using cellular phone with earpiece (QCPE); noisy conditions face to face (NFF); noisy conditions using cellular phone (NCP); and noisy conditions using cellular phone with earpiece (NCPE). In each condition, participants performed spontaneous speech, a standardized reading passage, and sustained voicing. Sound pressure levels (dB SPL) and fundamental frequencies (F(0)[Hz]) were measured. Subjects completed a 100-mm visual analog scale measuring vocal effort after each speaking scenario. Statistical analysis was performed using analysis of variance (ANOVA). There was a significant difference in dB SPL and F(0) between all quiet conditions relative to all noisy conditions (P<0.001). There was no difference in cellular phone use relative to any other conversational condition in mean dB SPL, respective of ambient noise. Vocal effort was rated greater for noisy conditions compared with quiet conditions. Cellular phone use does not lead to a significant change in voice production relative to other speaking conditions. Voice problems associated with cellular phone use may simply be a function of the increased amount of voice use and increased vocal loudness (Lombard effect) associated with speaking in noisy situations rather than a variable inherent to the phone.