What defines the characteristic voice of individuals with hyperkinetic dysarthria?

The characteristic voice of individuals with hyperkinetic dysarthria is defined by a harsh quality and a notable variation in loudness. This dysarthria is often associated with conditions that lead to involuntary movements of the speech mechanisms, resulting in a voice that can be inconsistent and unpredictable. Such involuntary movements can disrupt the control of voicing and intensity, leading to fluctuations in volume and a harsh sound quality. This distinctiveness contrasts with more consistent qualities of voice, such as those seen in other types of dysarthria where pitch and loudness might remain stable. In hyperkinetic dysarthria, the irregular control of vocal fold function contributes significantly to the perception of the voice, making it seem harsher and more variable in terms of loudness.