1. To speak, we use structures on the left side of the brain, which work in synchrony to produce communication.
two. When uttering sentences, Wernicke’s area begins to give feedback on the words, checking whether they sound correctly within the sentence.
3. The Broca area processes language and plans the articulation of the word so that it is pronounced correctly.
4. The motor area triggers the muscular response of the tongue, larynx and lips – essential for pronouncing words in the movement of speech.
5. In people who stutter, the electrical signals between the speech centers follow an imprecise and out of sync sequence. Anomalies such as cracks or broken bundles in the motor area prevent electrical signals from being transmitted correctly.
6. Disturbances in the basal ganglia, responsible for the motor sequence, cause problems in the initiation of speech movements.
7. With irregular commands when pronouncing words and moving muscles, the person stutters. Some people who stutter may also have involuntary movements, such as clicking their tongue or shaking their head backwards. The incidence of stuttering is four times more frequent in men than in women.
Why don’t stutterers stutter when they sing?
Because the part of the brain used for singing is different than for speech. “The brain has two premotor systems: medial and lateral. The first is active when the person speaks and the other when they produce more rhythmic sounds”, explains Cristiane Moço Canhetti de Oliveira, speech therapist. So, even if there is a problem in the speech area, it may not affect singing. Prolonged syllables, emitted during singing, also minimize the problem. The cause of stuttering is still unknown, but it is known to be related to both genetic factors and psychological traits and trauma.
SOURCES Ana Maria Schiefer, speech therapist, doctor in human communication disorders at Unifesp-EPM and professor at Unifesp-EPM; Cristina Dias, speech therapist and master in linguistics from UERJ; and Leila Nagib, professor at the Faculty of Medicine at UFRJ