From Ask Dr Wiki
Submitted by Margo Benjamin, M.D. New York Presbyterian Hospital, Weill Cornell Medical Center
In Kaplan and Sadock's Comprehensive Textbook of Psychiatry prosody is defined as "the emotional tone of language". Indeed it is the melodious quality, the inflections in the voice that reveal the emotional aspects of speech. Prosody is affected by a variety of psychiatric and neuropsychiatric illnesses. During the history taking part of a diagnostic interview, prosody is one of the first characteristics of speech that stands out when it is outside of the normal range. The normal range is quite varied as it is influenced by not only the language that is spoken, but also by regional dialects, cultural backgrounds as well as the content of the speech itself.
Aprosodias are disorders in the ability to express (executive aprosody) or understand (receptive aprosody) the emotional overlay of speech. Aprosodias can be acquired via specific brain lesions. Executive prosody - which can be tested by asking the patient to repeat a neutral sentence with different emotions (anger, fear, sadness) - is affected by lesions of the right premotor cortex or the basal ganglia. Receptive prosody - which can be tested by the examiner repeating a neutral sentence with different emotions and asking the patient which emotion is being conveyed - is affected by lesions of the posterior superior right temporal lobe.
Prosody is affected by many psychiatric illnesses, therefore abnormalities of prosody are not symptomatic of a particular disorder. Patients with severe depression, schizophrenia and those with pervasive developmental disorders often present with characteristic abnormalities of prosody. The severely depressed patient may have a monotonous, affect neutral pattern of speech which is virtually devoid of emotional content. Patients with schizophrenia may present with abnormal modulation of emphasis and volume or unusual accents. Some patients with pervasive developmental disorders - in particular autism and Asperger's disorder have characteristic speech patterns which are monotonous, robotic, or singsong in quality.