Dysprosody

Dysprosody, which may manifest as pseudo-foreign accent syndrome, refers to a disorder in which one or more of the prosodic functions are either compromised or eliminated completely. Dysprosody, which may manifest as pseudo-foreign accent syndrome, refers to a disorder in which one or more of the prosodic functions are either compromised or eliminated completely. Prosody refers to the variations in melody, intonation, pauses, stresses, intensity, vocal quality, and accents of speech. As a result, prosody has a wide array of functions, including expression on linguistic, attitudinal, pragmatic, affective and personal levels of speech. People diagnosed with dysprosody most commonly experience difficulties in pitch or timing control. People diagnosed with the condition can comprehend language and vocalize what they intend to say, however, they are not able to control the way in which the words come out of their mouths. Since dysprosody is the rarest neurological speech disorder discovered, not much is conclusively known or understood about the disorder. The most obvious expression of dysprosody is when a person starts speaking in an accent which is not their own. Speaking in a foreign accent is only one type of dysprosody, as the condition can also manifest itself in other ways, such as changes in pitch, volume, and rhythm of speech. It is still very unclear as to how damage to the brain causes the disruption of prosodic function. The only form of effective treatment developed for dysprosody is speech therapy. Dysprosody is usually attributed to neurological damage, such as brain tumors, brain trauma, brain vascular damage, stroke and severe head injury. To better understand the causes of the condition, 25 cases of dysprosody diagnosed between 1907-1978 were examined more closely. It was found that the majority developed dysprosody after a cerebrovascular accident, while another 6 cases developed after a head trauma. In that same study, 16 of the patients were female, while 9 were male. However, there has been no conclusive evidence that gender affects the onset of dysprosody. There has been no evidence that ethnicity, age, or genetics has any impact on the development of dysprosody. In another reported case in 2004, a patient presented with dysprosody under interesting circumstances. The patient underwent surgery to correct a Reinke's edema, which originates in the vocal folds of the larynx. After the surgery, however, she began speaking in a foreign German accent. Neurological examinations were carried out on the patient through magnetic resonance imaging, but the results were completely normal. The only conclusion the doctors could make was that the surgery somehow changed the patient's vocal identification causing the new voice pattern. It was possible that the patient suffered a lack of oxygen to the brain during the surgery, which would have gone undetected by the resonance imaging, causing dysprosody. Although most causes of dysprosody are due to neurological damage, this case study shows that there can be other causes which are not necessarily neurologically based. Dysprosody is 'characterized by alterations in intensity, in the timing of utterance segments, and in rhythm, cadency, and intonation of words.' These differences cause a person to lose the characteristics of their particular individual speech. While the individual's personality, sensory comprehension, motor skills, and intelligence all remain intact, their grammar as well as vocal emotional capacity can be affected. Prosodic control is essential to speech delivery because it establishes vocal identity, since each individual's voice has unique characteristics. There are two types of dysprosody, linguistic and emotional, that each present with slightly different symptoms. It is possible that one can present with both forms of dysprosody. Dysprosody works on a linguistic level in that it specifies the intent of one's speech. For example, prosody is responsible for verbal variations in interrogative versus declarative statements and serious versus sarcastic remarks. Linguistic dysprosody refers to the diminished ability to verbally convey aspects of sentence structure, such as placing stress on certain words for emphasis or using patterns of intonation to reveal the structure or intention of an utterance. For example, individuals with linguistic dysprosody may have difficulty distinguishing the production of interrogative and declarative sentences, switching or leaving out the expected rising and falling shift, respectively. Thus, linguistic dysprosody alters an individual's vocal identity and impairs verbal communication. Emotional dysprosody deals with a person's ability to express emotions through their speech as well as their ability to understand emotion in someone else's speech. Whenever we speak, whether we realize it or not, there are nonverbal aspects of our speech that reveal information about our feelings and attitude. There has been strong evidence that dysprosody does affect the ability to express emotion, however the severity may vary depending on what part of the brain has been damaged. Studies have shown that the ability to express emotional information is dependent on motor, perceptual, and neurobehavioral functions all working together in a specific way. A person suffering from dysprosody would not be able to accurately convey emotion vocally, such as through pitch or melody, or make any conclusion about another person's feeling through his speech. Regardless of the inability to vocally express feeling through prosodic controls, emotions are still formed and felt by the individual. Since there are many different factors which contribute to emotional understanding of speech, it makes it much more complicated to understand. After experiencing brain injury, some people may begin speaking in an accent not native to their country of origin, as discussed in the preceding sections, but more common forms of dysprosody consist of alterations in vocal pitch, timing, rhythm, and control, not necessarily resulting in a foreign dialect. In addition, there have been some cases in which seizures began to develop in patients also suffering from dysprosody, but no decisive conclusions connecting dysprosody and seizure activity have been made.Dysprosody can last for differing durations, from a few months to years, although the reason seems to be unclear. There are several different types of dysprosody which have been classified. The most common types of dysprosody are associated with dysarthria and developmental coordination disorder, which affect motor processing in speech. Among the most studied types are: