Editing Vocal cord nodule (section)

=== Acoustic signs ===
Major acoustic signs of vocal fold nodules involve changes in the frequency and the intensity of the voice. The fundamental frequency, an acoustic measure of voice pitch, may be normal. However, the range of pitches the individual is capable of producing may be reduced,<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /> and it may be especially difficult to produce pitches in the higher range.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /><ref name="pmid19779347" /> The intensity of the voice, an acoustic measure of amplitude or loudness, may also be normal.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /> However, the individual's amplitude range may be reduced as well.<ref name="Verdolini et al 2014 Vocal Fold Nodules" /><ref name="Colton et al 2006 Nodules" /> Perturbations or variations in frequency, known as [[jitter]], and in amplitude, known as shimmer, may be increased.<ref name="Colton et al 2006 Nodules" />