Treatment Methods of Auditory Comprehension in Individuals with Aphasia

Understanding language is significant to social reciprocity within family, peer groups, professional settings, and everyday society. When an individual is diagnosed with aphasia, specifically Wernicke’s aphasia or global aphasia, there are many challenges ahead of them, including the ability to understand spoken language, as auditory comprehension may an area of deficit. There is ongoing research conducted on treatment methods, delivered by speech-language pathologists, to support and increase auditory comprehension in individuals with aphasia.

Aphasia is an acquired communication disorder, which impairs a person’s ability to process language (Learn about Aphasia). Strokes account for 80-90% of cases of adults with aphasia in the United States. Other causes of aphasia include, infections in the brain, brain tumors, nutritional deficiency, or toxemia (Brookshire & McNeil, 2015). There are two types of stroke or cerebrovascular accident (CVA); ischemic and hemorrhagic stroke. An ischemic stroke occurs in the brain when an artery is blocked which causes the brain to lose bloody supply. On the other hand, a hemorrhagic stroke is when a blood vessel in the brain ruptures. Both ischemic and hemorrhagic strokes can cause aphasia in individuals.

There are eight foremost types of aphasia including; global, mixed transcortical, Broca’s, transcortical motor, Wernicke’s aphasia, transcortical sensory, conduction, and anomic. Each classification of aphasia has defining characteristics, including repetition, fluency, word finding and auditory comprehension, which range in severity dependent on the type of aphasia.

Auditory comprehension is an individual’s ability to understand and process information and language. Auditory comprehension can affect individuals with aphasia ranging from mild (i.e. word level) to severe (i.e. conversation level) causing auditory deficits identified and derived from the Schuell’s classification. These auditory comprehension deficits include; slow rise time, noise build-up, retention deficit, information capacity, and intermittent auditory imperception.

Slow rise time indicate difficulty for individuals to comprehend the final part of the message they are receiving. On the contrary, individuals with noise build-up, often respond more accurately to the beginning part of the receiving message. These individuals often benefit from gradually increasing the length and complexity of the messages. Similarly, retention deficit indicates an individual’s difficulty comprehending messages as related to length and complexity, but the communication breakdown can occur in both the initial and final portions of the message. Information capacity deficit indicate an individual has difficulty receiving and process information at the same time. These individuals benefit from insertions of pauses within a message to process information. Finally, auditory comprehension deficits affect intermittent auditory imperception as auditory processing can be unpredictable. (Weissling, Roberts, Kaploun, 2018).

Auditory comprehension deficits are more common in individuals with global or Wernicke’s aphasia. Studies within the past ten years, have shown a variation of treatment methods to increase auditory comprehension for these individuals. These treatments include but are not limited to, high intensity word-picture identification, use of the pharmaceutical drug called, piracetam, sentence comprehension treatment, and cathodal transcranial direct stimulation of the Wernicke’s area. (Knollman-Porter, Dietz, & Dahlem, 2018).

 As these treatment methods are analyzed, it is important to note the range of deficits for individuals with aphasia, therefore a singular treatment that has not been proven effective with all individuals or resulted in a full recovery of auditory comprehension deficits. However, extensive research studies indicate multiple treatment methods that result in improvements and positive benefits.

As previously mentioned, individuals with aphasia have difficulties with auditory comprehension, awareness of communication breakdowns, and utilization of compensatory strategies. Furthermore, phonological, and semantic processes facilitate discrimination of sounds, and meanings of words, phrases, and sentences, which explains why when auditory comprehension is affected, there is a communication and comprehension breakdown. In 2018, a treatment study completed by Knollman-Porter, Dietz, & Dahlem, examined individuals with severe aphasia and the effects of intense auditory comprehension treatment. These researchers used basic semantic comprehension training methods (i.e. answering yes and no questions, matching words to pictures) as well as word retrieval treatments. The combination of these two treatment methods facilitate an increase in auditory comprehension, word naming, word retrieval for individuals with aphasia. Although the findings of this treatment in this study were found to improve response accuracy for the participants, a larger sample size would be needed to prove efficacy. (Knollman-Porter, Dietz, & Dahlem, 2018)

Another treatment method examined was melodic intonation therapy. The study of this treatment included a participant with global aphasia following a right hemisphere hemorrhagic stroke. This individual completed a 7-week treatment program that used melodic intonation therapy, MIT. Treatment sessions were held five times a week for two and a half hour sessions per day. The Aphasia Diagnostic Profiles, The American Speech Language Hearing Association Functional Assessment of Communication Skills and the Stroke and Aphasia Quality of Life Scale-39 were assessed before and after treatment sessions to observe the treatment related changes. The participant had a positive response to MIT which reflected in the results of the treatment. The individual completed the elementary level in 25 sessions and progressed through the intermediate level until the end of the treatment session cycle at treatment session 30. The Aphasia Diagnostic Profiles suggested that participant had improved auditory comprehension, repetition, phrase length, gestures, and functional communication. Although the results for this individual showed improvements, larger studies sizes are necessary to compare and measure efficacy. Additionally, this study recognized the need to identify individuals who would benefit from this type of treatment. (Morrow-Odom & Swann, 2015)

As melodic intonation therapy may not be a treatment method all individuals with aphasia will benefit from, there are other treatments which use pharmaceutical drugs. In this study, long-term use of the pharmaceutical drug called, piracetam, was examined as a treatment method for improved auditory comprehension for individuals with aphasia. Prior to this study, piracetam has been proved to have mild beneficial effects on post-stroke patients with aphasia. During this study, there were two groups identified; the placebo group and the group receiving the piracetam medication. After six months of treatment, the results of this treatment were analyzed and showed the only significant difference between the placebo group and the piracetam groups were the effect the drug had auditory comprehension. For few individuals who took the piracetam, there was a noticeable difference and improved auditory comprehension. However, all individuals participating in this study experienced a spontaneous recovery, although the degree cannot be determined. While, this treatment method cannot be proven to be effective at this time, there continues to be significant need for a post-stroke medication for individuals to aid in treatment. (Güngör, Terzi, & Onar, 2011)

Another treatment method used for individuals with aphasia is sentence comprehension treatment. This study examined the effect of sentence comprehension treatment on the test of Syntactic Effects on Discourse Comprehension. This treatment study assessed the effects of using different complex syntax within a sentence to improve comprehension of complex passages. There were 40 participants with aphasia who received this sentence comprehension treatment. They were given one of two syntactic comprehension tasks to complete. One task was object manipulation (i.e. picking up a coin off the table) and the second task presented was sentence-to-picture-matching. The results of the sentence comprehension treatment conclude that the individuals were able to comprehend trained sentences regardless of if the task was object manipulation or sentence-picture-matching. Although auditory comprehension improved within trained sentences, this treatment has not been proven to generalize to other activities, sentences, or natural environment settings. (Kiran, Des Roches, Villard, & Tripodis, 2015)

The next treatment study examined for improving auditory comprehension in individuals with aphasia is a cathodal transcranial direct stimulation of the Wernicke’s area. Cathodal stimulation is when anions (-) are discharged into the body as current flows from the cathode (-) through the tissue and back to anode. On the contrary, Anodal stimulation is when cations (+) are discharged into the body as current flows from the anode (+), thought the tissue, and back to the cathode (-). Anodal tDCS is usually used for individuals with aphasia as to stimulate the left hemisphere of the brain. This study is examining the effects by doing the inverse treatment. (Brookshire & McNeil, 2015).

Transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) are approaches which are “non-invasive brain stimulation Brookshire & McNeil, 2015hat have been shown to modulate excitability in the brain” (You, Kim, Chun, Jung, & Park, 2011). This treatment study indicates the use of the transcranial direct current stimulation as is reported by patients to be more comfortable, cover a larger area, concurrently target speech training, and has less side effects compared to the rTMS. “The left superior temporal cortex has been associated with language processing and improved comprehension in patients with aphasia, but activation of the right hemisphere may facilitate transcallosal disinhibition which is less conductive to language recovery in right-handed acute post-stroke aphasia patients.” This treatment study examined the effects of increase auditory comprehension with the stimulation of 21 patients. These patients had global aphasia due to stroke. The results of this treatment indicate the patients made significant improvements in their spontaneous speech, and auditory comprehension over a two-week trial. This suggests greater improvements by suppressing the right hemisphere rather than activating the left hemisphere with anodal tDCS.

Although these treatments are methodical different, they all are targeting the same goal, which is to improve auditory comprehension in individuals with aphasia by creating new neural pathways in the brain. Whether the treatment is through singing, sentence repetition, medication, picture-matching or stimulation, the efficacy for each individual can vary. Continual research of these treatment methods is necessary in order to provide a complete and thorough analysis. Additionally, research should also examine the effects of combination treatment; using more than one treatment method to complement each other and effectively increase auditory comprehension.

References

• Brookshire, Robert H., and Malcolm R. Mcneil. Introduction to Neurogenic Communication Disorders, Elsevier, 2014. ProQuest Ebook Central, https://ebookcentral.proquest.com/lib/novasoutheastern/detail.action?docID=2072455.
• Dickey MW, & Yoo H. (2010). Predicting outcomes for linguistically specific sentence treatment protocols. Aphasiology, 24(6–8), 787–801. https://doi-org.ezproxylocal.library.nova.edu/10.1080/02687030903515354
• Güngör L, Terzi M, & Onar MK. (2011). Does long term use of piracetam improve speech disturbances due to ischemic cerebrovascular diseases? Brain & Language, 117(1), 23–27. https://doi-org.ezproxylocal.library.nova.edu/10.1016/j.bandl.2010.11.003
• Kiran, S., Des Roches, C., Villard, S., & Tripodis, Y. (2015). The effect of a sentence comprehension treatment on discourse comprehension in aphasia. Aphasiology, 29(11), 1289–1311. https://doi-org.ezproxylocal.library.nova.edu/10.1080/02687038.2014.997182
• Knollman-Porter, K., Dietz, A., & Dahlem, K. (2018). Intensive Auditory Comprehension Treatment for Severe Aphasia: A Feasibility Study. American Journal of Speech-Language Pathology, 27(3), 936–949. https://doi-org.ezproxylocal.library.nova.edu/10.1044/2018pass:[_]AJSLP-17-0117
• Learn about Aphasia. (n.d.). Retrieved October 15, 2018, from http://www.aphasia.org/
• Morrow-Odom, K. L., & Swann, A. B. (2013). Effectiveness of melodic intonation therapy in a case of aphasia following right hemisphere stroke. Aphasiology, 27(11), 1322–1338. https://doi-org.ezproxylocal.library.nova.edu/10.1080/02687038.2013.817522
• Weissling, K., Dr., Roberts, E., Dr., & Kaploun, L., Dr. (2018, September 13). History and Classification of Aphasia. Lecture.
• You DS, Kim DY, Chun MH, Jung SE, & Park SJ. (2011). Cathodal transcranial direct current stimulation of the right Wernicke’s area improves comprehension in subacute stroke patients. Brain & Language, 119(1), 1–5. Retrieved from http://search.ebscohost.com.ezproxylocal.library.nova.edu/login.aspx?direct=true&db=ccm&AN=104578364&site=ehost-live