Since the 1980s, photoacoustic (PA) measurements have been employed for studies related to human skin, such as skin permeation studies. One frequent problem when it comes to in vivo measurements in humans is the poor signal-to-noise ratio (SNR) that may result from different causes, including the movements of the volunteers during measurements. The present work is aimed to analyze the possible influence of ambient music (keyboard played by a musician at the laboratory, at constant sound level) on skin measurements performed in vivo in humans. Analysis was performed through PA measurements employing a tungsten lamp as the light source. Sequential measurements were performed for three different conditions (in random sequence) for each volunteer: 1) with no music; 2) with the volunteer hearing fast music; 3) with the volunteer listening to slow music. Results show that the PA signal level and phase (average values) do not change, but SNR is influenced by the conditions to which the volunteer is exposed: slow music tends to keep SNR at the same level as that presented with no music, while fast music induces a higher fluctuation in the signal, thus decreasing the SNR value.
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