Which of the following statements about jitter and shimmer in voice disorders is true?

The statement that more than average amounts of jitter and shimmer may reflect disorders is correct because jitter and shimmer are quantitative measures used to assess voice quality. Jitter refers to the frequency variation between cycles of vocal fold vibrations, while shimmer refers to the amplitude variation. In healthy voices, these measures are typically lower, indicating stable and consistent vocal fold function. When levels of jitter and shimmer are elevated, it can suggest irregularities in vocal fold vibration that are commonly associated with voice disorders. Therefore, an increase in these measures can point to potential issues with the voice quality, suggesting that the individual may be experiencing a voice disorder or dysfunction.

The other options do not accurately reflect the relationship between jitter and shimmer and voice health. For instance, jitter and shimmer are not reliable indicators for lie detection, nor do higher levels indicate healthy voice functioning. Additionally, while some variation is normal, significant deviations are more likely to suggest problems rather than indicate normal voice qualities.