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Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
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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. Essentially, people diagnosed with the disease 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 disease 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.
Given the previously stated signs and symptoms the following behaviors are often seen in people with aphasia as a result of attempted compensation for incurred speech and language deficits:
- Self-repairs: Further disruptions in fluent speech as a result of mis-attempts to repair erred speech production.
- Speech disfluencies: Include previously mentioned disfluencies including repetitions and prolongations at the phonemic, syllable and word level presenting in pathological/ severe levels of frequency.
- Struggle in non-fluent aphasias: A severe increase in expelled effort to speak after a life where talking and communicating was an ability that came so easily can cause visible frustration.
- Preserved and automatic language: A behavior in which some language or language sequences that were used so frequently, prior to onset, they still possess the ability to produce them with more ease than other language post onset.
People with aphasia may experience any of the following behaviors due to an acquired brain injury, although some of these symptoms may be due to related or concomitant problems such as dysarthria or apraxia and not primarily due to aphasia. Aphasia symptoms can vary based on the location of damage in the brain. Signs and symptoms may or may not be present in individuals with aphasia and may vary in severity and level of disruption to communication. Often those with aphasia will try to hide their inability to name objects by using words like "thing". So when asked to name a pencil they may say it is a thing used to write.
- Inability to comprehend language
- Inability to pronounce, not due to muscle paralysis or weakness
- Inability to speak spontaneously
- Inability to form words
- Inability to name objects (anomia)
- Poor enunciation
- Excessive creation and use of personal neologisms
- Inability to repeat a phrase
- Persistent repetition of one syllable, word, or phrase (stereotypies)
- Paraphasia (substituting letters, syllables or words)
- Agrammatism (inability to speak in a grammatically correct fashion)
- Dysprosody (alterations in inflexion, stress, and rhythm)
- Incomplete sentences
- Inability to read
- Inability to write
- Limited verbal output
- Difficulty in naming
- Speech disorder
- Speaking gibberish
- Inability to follow or understand simple requests
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:
- Flaccid dysarthria is characterized by little control over pitch and voice volume, reduced speech rate, and impaired voice quality
- Hypokinetic dysarthria is characterized by harsh voice quality, monotone, reduced volume and breathiness
- Ataxic dysarthria is characterized by harsh voice quality, reduced speech rate, and poor volume and pitch control
- Developmental verbal dyspraxia is characterized by monotone and poor volume control
There can also be some emotional and mental side effects to dysprosody. Each individual has a distinct voice characterized by all the prosodic elements. Once a person loses control of the timing, pitch, melody, etc. of his speech, he can also feel a sense of loss of personal identity, which can sometimes lead to depression.
Aprosodia is a neurological condition characterized by the inability of a person to properly convey or interpret emotional prosody. Prosody in language refers to the ranges of rhythm, pitch, stress, intonation, etc. These neurological deficits can be the result of damage of some form to the non-dominant hemisphere areas of language production. The prevalence of aprosodias in individuals is currently unknown, as testing for aprosodia secondary to other brain injury is only a recent occurrence.
One cause of aprosodia is suffering brain trauma to one of several specific areas of the brain, resulting in the inability to properly process or convey
emotional cues. This brain damage can occur in the form of ischemic damage from stroke, removal during surgery, brain lesions, or trauma such as a localized bullet wound. It is worth noting however, that this localization occurs over a range of areas that can vary from person to person and more research is required to further define these areas. Diagnostic confirmation of aprosodia using brain scanning techniques is a relatively recent occurrence, at least with respect to quantitative specificity. As brain imaging techniques are refined to allow for greater temporal and spatial resolution, it is hoped that more will be able to be learned about aprosodias at a functional anatomical level.