Additional exclusion criteria for developmental stuttering only include: language and/or cognitive functioning lower than 1 standard deviation below the age-adjusted mean value on screening tests, left-handedness on the Edinburgh handedness questionnaire; movement disorders (e.g., Huntington disease, chorea, myoclonus, Gilles de la Tourette syndrome, Parkinson's disease, progressive supranuclear palsy, and neuroleptic-induced syndromes), brain tumors, history of traumatic brain injury with loss of consciousness, genetic diseases of the CNS (e.g., chromosomal diseases, metabolic disorders, diffuse sclerosis), chronic infections of the nervous system (e.g., bacterial, vial, parasitic, fungal and yeast), ataxias (inherited and acquired), myopathies (e.g., progressive muscular dystrophies, familial periodic paralysis, congenital disorders of muscle, myoglobinuria, polymyositis), disorders of the neuromuscular junction (e.g., myasthenia gravis), demyelinating diseases (e.g., multiple sclerosis, central pontine myelinolysis), other brain abnormalities, schizophrenia, alcoholism, long-lasting drug dependence, major and/or bipolar depression, obsessive-compulsive disorder, vocal fold paralysis or paresis, joint abnormality, or neoplasm, and history of swallowing disorders, airway obstruction.