That happens when the speech muscles and nerves fail to function properly, which make it harder for the brain to coordinate with the various parts of the speech mechanism in the body. This stammering type is referred to in speech pathology terms as a neurogenic disorder. It usually occurs in children as well as adults who have brain injury or those who have suffered from stroke. In rare cases, lesions or structural flaws in the part of the brain that takes charge of a person’s motor speech trigger this neurogenic condition.
Scientists explain that some forms of stammering originate from the brain’s activities such as reasoning and thought. This type of stammering is called psychogenic disorder. Compared to other forms of stammering discussed earlier, the psychogenic origin rarely affects people’s speech. It happens to people who have undergone extreme mental stress or trauma or those who have certain types of mental disorder.
However, experts believe that these emotional and mental problems lead to stuttering instead of causing the speech condition. For example, people who usually stammer may have to endure several emotional troubles like speaking on the telephone or in public. Others dread meeting new people. In some cases, people stammer when they are intensely excited, enraged, scared, or shocked. Aside from these extreme emotions, fatigue, intense pressure, and self-consciousness may also increase a person’s tendency to stutter while speaking.
Interestingly, many people who usually stutter can speak fluently when they talk to themselves, speak with a few friends, or sing with a crowd or group. The reason for that is still unclear, though.