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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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The most effective course of treatment for dysprosody has been speech therapy. The first step in therapy is practice drills which consist of repeating phrases using different prosodic contours, such as pitch, timing, and intonation. Typically a clinician will say either syllables, words, phrases, or nonsensical sentences with certain prosodic contours, and the patient repeats them with the same prosodic contours. Treatment following the lines of the principles of motor learning (PML) was found to improve the production of lexical stress contrasts. Once a patient is able to effectively complete this drill, they can start with more advanced forms of speech therapy. Upon completion of therapy, most people can identify prosodic cues in natural situations, such as normal conversation. Speech therapy has proven most effective for linguistic dysprosody because therapy for emotional dysprosody requires much more effort and is not always successful. One way that people learn to cope with emotional dysprosody is to explicitly state their emotions, rather than relying on prosodic cues.
Over time, there have also been cases of people suffering from dysprosody gaining their native accent back with no course of treatment. Since the part of the brain responsible for dysprosody has not definitely been discovered, nor has the mechanism for the brain processes which cause dysprosody been found, there has not been much treatment for the disease by means of medication.
The methods of treatment are being evaluated and changed through several iterations to reach the most beneficial treatment for those with aprosodia. Although the biggest limitation on progress of aprosodia treatment is sample size, some significant data has been found to influence each subsequent phase of study. The Rosenbek lab at the University of Florida is currently in a new phase of treatment study based on combinations of the cognitive-linguistic and imitative therapies delivered in a randomized fashion in an effort to gain more insight into what most prominently affects aprosodia treatment.
The intensity of aphasia therapy is determined by the length of each session, total hours of therapy per week, and total weeks of therapy provided. There is no consensus about what “intense” aphasia therapy entails, or how intense therapy should be to yield the best outcomes. A 2016 Cochrane review of speech and language therapy for people with aphasia found that treatments that are higher intensity, higher dose or over a long duration of time led to significantly better functional communication but people were more likely to drop out of high intensity treatment (up to 15 hours per week).
Intensity of therapy is also dependent on the recency of stroke. People with aphasia react differently to intense treatment in the acute phase (0–3 months post stroke), sub-acute phase (3–6 months post stroke), or chronic phase (6+ months post stroke). Intensive therapy has been found to be effective for people with nonfluent and fluent chronic aphasia, but less effective for people with acute aphasia.> People with sub-acute aphasia also respond well to intensive therapy of 100 hours over 62 weeks. This suggests people in the sub-acute phase can improve greatly in language and functional communication measures with intensive therapy compared to regular therapy.
When addressing Wernicke’s aphasia, according to Bakheit et al. (2007), the lack of awareness of the language impairments, a common characteristic of Wernicke’s aphasia, may impact the rate and extent of therapy outcomes. Klebic et al. (2011) suggests that people benefit from continuing therapy upon discharge from the hospital to ensure generalization. Robey (1998) determined that at least 2 hours of treatment per week is recommended for making significant language gains. Spontaneous recovery may cause some language gains, but without speech-language therapy, the outcomes can be half as strong as those with therapy.
When addressing Broca’s aphasia, better outcomes occur when the person participates in therapy, and treatment is more effective than no treatment for people in the acute period. Two or more hours of therapy per week in acute and post-acute stages produced the greatest results. High intensity therapy was most effective, and low intensity therapy was almost equivalent to no therapy.
People with global aphasia are sometimes referred to as having irreversible aphasic syndrome, often making limited gains in auditory comprehension, and recovering no functional language modality with therapy. With this said, people with global aphasia may retain gestural communication skills that may enable success when communicating with conversational partners within familiar conditions. Process-oriented treatment options are limited, and people may not become competent language users as readers, listeners, writers, or speakers no matter how extensive therapy is. However, people’s daily routines and quality of life can be enhanced with reasonable and modest goals. After the first month, there is limited to no healing to language abilities of most people. There is a grim prognosis leaving 83% who were globally aphasic after the first month they will remain globally aphasic at the first year. Some people are so severely impaired that their existing process-oriented treatment approaches offer signs of progress, and therefore cannot justify the cost of therapy.
Perhaps due to the relative rareness of conduction aphasia, few studies have specifically studied the effectiveness of therapy for people with this type of aphasia. From the studies performed, results showed that therapy can help to improve specific language outcomes. One intervention that has had positive results is auditory repetition training. Kohn et al. (1990) reported that drilled auditory repetition training related to improvements in spontaneous speech, Francis et al. (2003) reported improvements in sentence comprehension, and Kalinyak-Fliszar et al. (2011) reported improvements in auditory-visual short-term memory.
Most acute cases of aphasia recover some or most skills by working with a speech-language pathologist. Recovery and improvement can continue for years after the stroke. After the onset of Aphasia, there is approximately a six-month period of spontaneous recovery; during this time, the brain is attempting to recover and repair the damaged neurons. Improvement varies widely, depending on the aphasia's cause, type, and severity. Recovery also depends on the person's age, health, motivation, handedness, and educational level.
There is no one treatment proven to be effective for all types of aphasias. The reason that there is no universal treatment for aphasia is because of the nature of the disorder and the various ways it is presented, as explained in the above sections. Aphasia is rarely exhibited identically, implying that treatment needs to be catered specifically to the individual. Studies have shown that, although there is no consistency on treatment methodology in literature, there is a strong indication that treatment in general has positive outcomes. Therapy for aphasia ranges from increasing functional communication to improving speech accuracy, depending on the person's severity, needs and support of family and friends. Group therapy allows individuals to work on their pragmatic and communication skills with other individuals with aphasia, which are skills that may not often be addressed in individual one-on-one therapy sessions. It can also help increase confidence and social skills in a comfortable setting.
Evidence dose not support the use of transcranial direct current stimulation (tDCS) for improving aphasia after stroke.
Specific treatment techniques include the following:
- Copy and Recall Therapy (CART) - repetition and recall of targeted words within therapy may strengthen orthographic representations and improve single word reading, writing, and naming
- Visual Communication Therapy (VIC) - the use of index cards with symbols to represent various components of speech
- Visual Action Therapy (VAT) - typically treats individuals with global aphasia to train the use of hand gestures for specific items
- Functional Communication Treatment (FCT) - focuses on improving activities specific to functional tasks, social interaction, and self-expression
- Promoting Aphasic's Communicative Effectiveness (PACE) - a means of encouraging normal interaction between people with aphasia and clinicians. In this kind of therapy the focus is on pragmatic communication rather than treatment itself. People are asked to communicate a given message to their therapists by means of drawing, making hand gestures or even pointing to an object
- Melodic Intonation Therapy (MIT) - aims to use the intact melodic/prosodic processing skills of the right hemisphere to help cue retrieval of words and expressive language
- Other - i.e. drawing as a way of communicating, trained conversation partners
Semantic feature analysis (SFA) -a type of aphasia treatment that targets word-finding deficits. It is based on the theory that neural connections can strengthened by using using related words and phrases that are similar to the target word, to eventually activate the target word in the brain. SFA can be implemented in multiple forms such as verbally, written, using picture cards, etc. The SLP provides prompting questions to the individual with aphasia in order for the person to name the picture provided. Studies show that SFA is an effective intervention for improving confrontational naming.
Melodic intonation therapy is used to treat non-fluent aphasia and has proved to be effective in some cases. However, there is still no evidence from randomized controlled trials confirming the efficacy of MIT in chronic aphasia. MIT is used to help people with aphasia vocalize themselves through speech song, which is then transferred as a spoken word. Good candidates for this therapy include people who have had left hemisphere strokes, non-fluent aphasias such as Broca's, good auditory comprehension, poor repetition and articulation, and good emotional stability and memory. An alternative explanation is that the efficacy of MIT depends on neural circuits involved in the processing of rhythmicity and formulaic expressions (examples taken from the MIT manual: “I am fine,” “how are you?” or “thank you”); while rhythmic features associated with melodic intonation may engage primarily left-hemisphere subcortical areas of the brain, the use of formulaic expressions is known to be supported by right-hemisphere cortical and bilateral subcortical neural networks.
According to the National Institute on Deafness and Other Communication Disorders (NIDCD), involving family with the treatment of an Aphasic loved one is ideal for all involved, because while it will no doubt assist in their recovery, it will also make it easier for members of the family to learn how best to communicate with them.
The two main forms of treatment are cognition based and imitation based. Cognitive treatments attempt to rebuild the "emotional toolbox" of those with aprosodia. The basis for this treatment is the belief that there exists a defined set of emotional responses that can be chosen for a given scenario. Choosing the proper emotional response can very much be likened to choosing the proper word when describing an object, and this deficiency can be likened to Broca's Aphasia but for emotions. Imitative treatments attempt to help "kickstart" the motor systems involved in the production of both vocal and facial emotive gestures. The basis for this treatment is the belief that the pathways responsible for the motor elements of expressive prosody were damaged. It is hypothesized that the motor damage occurs at the level of planning as well as the level of execution.
Dysprosody is an impairment in the prosodic elements such as rhythm, timing, melody, stress, pitch and intonation. It primarily results from neurological damage that can be caused by tumors, stroke, or severe head injury. There have been several hypotheses proposed discussing the area of the brain responsible for prosodic control, but since prosodic elements are so diverse, its organization in the brain is still unclear. There are different types of dysprosody, including linguistic and emotional, which present different symptoms. The only course of treatment proven to be effective is speech therapy, although normal speech may naturally resume. Currently, there has been more research regarding dysprosody's link to other diseases, in particular Parkinson's disease, but also Huntington's disease, and gelastic epilepsy to name a few.