Psycholinguistics/Aphasia

IntroductionEdit

Aphasia is a language disorder caused by damage suffered to certain portions of the brain that are involved in language perception and production. Depending upon the area that is affected, a person suffering from Aphasia may be able to speak fluently but not coherently, and vice versa. Aphasiology is the study of these linguistic deficits resulting from brain damage and through this study, much can be learned and inferred about the normal function of language and its organization within the brain. There are a variety of modern assessment tools through which aphasia can be studied in patients. The prognosis varies greatly and is dependent upon such factors as, site of the stroke, severity of the lesion, the age of the patient, and the type of aphasia acquired.

HistoryEdit

The word “Aphasia” is derived from the Greek word “aphatos”, meaning speechless. [1] Mentions of Aphasia in Greek Medicine are evident in which speechlessness accompanied convulsions are documented as resulting in paralysis of the right side of the body. Aphasia is again shown in literature from the Roman times in which authors such as Soranus of Ephesus noted the impairment of speech following paralysis of one part of the body. [1] Great advancements occurred from the 1800s to the 1860s in which clinical knowledge, theoretical formulation and neuropathology were developed and a working knowledge of the brain as associated with speech disorders was beginning to be understood more scientifically.

The most recent widespread acceptance of the brain's functioning is in the language localization theory in which different sections of the brain are responsible for the functioning of different bodily functions. The birth of this concept came with Franz Joseph Gall's theory of phrenology. Gall proposed that all mental functioning could be located on different sections of the brain and the advancement of a particular area resulted in a visible difference on a person's head. Although Franz Gall's theory of phrenology is now considered a pseudoscience, his localizationist assumptions were evidently working in the right direction as it is now possible to scientifically prove that certain sections of the brain are involved in different bodily functions. [2]

The theory of language localization gained furthur credit with significant findings attributed to Paul Broca in the 1860s. [2] The beginning of comprehensive Aphasia understanding came with Paul Broca’s research and subsequent description of his patient Laborgne's brain. In 1861, Broca published “Remarques sur le siège de la faculté du langage articulé: suivies d' une observation d'aphémie” in which he evidences for the localization of articulate speech in the frontal lobe. [1] Upon Leborgne’s death, Broca performed an autopsy and determined that the damage was suffered to the third convolution of the left frontal lobe, which is now commonly referred to as Broca’s area. [2] Stemming from his influential findings, was a revolution in medical and physioogical thinking as it pertained to the brain and the establishment of cerebral localization. Less than a decade later, Wernicke identified “sensory” aphasia as being localized to the temporal lobe. [1] Ludwig Lichtheim then branched off of Wernicke’s model, naming five other types of aphasia, pure word deafness, conduction aphasia, apraxia of speech, transcortical motor aphasia, and transcortical sensory aphasia.

As the mid 20th century approached, professionals specializing in language began searching for a revised model of understanding normal and abnormal language functioning. One professional by the name of Norman Geschwind formed the Geschwind model. Revisiting language localization theories, the model describes the interconnecting functions of a normally working human brain to produce speech and language comprehension. Aphasias were viewed as occurring along these interconnecting lines, disrupting spoken speech or comprehension, resulting in various symptoms. [1] Although the Geschwind model was a great contribution to the understanding of language, problems with it have been uncovered in recent years and a straying away from this understanding of language functioning has occurred. [3]


Advancements in imaging technology has propelled our understanding of the brain as it pertains to language and disorders such as aphasia. Voxel-based Lesion Symptom Mapping (VLSM) in particular, has allowed for medical professionals to determine more specifically where brain lesions lie and the tasks that are impaired because of them. VLSM's ability to identify white matter regions which can play causal roles in certain cognitive domains allows for professionals closely identify these problem regions. A 'voxel' is the three dimensional analog of a pixel and represents a volume of 1 cubic millimeter; The image produced displays 3 dimensional picture of the human brain as depicted in the picture to the right. Studies using VSLM have suggested that language functions are not as localized as the Geschwind model posits it to be. [4]

Forms of AphasiaEdit

Aphasia can be divided into three category types depending upon the quality of the deficit acquired. Fluent, non-fluent, and pure:

  • Fluent
Fluent aphasias are caused by impairment to language reception. These aphasic individuals have little issue with fluent verbal output but have difficulty in the language that they are speaking, which often seems like nonsense. Some fluent aphasias include: Wernicke’s Aphasia, Conduction Aphasia, and Anomic Aphasia. [5]
  • Non-fluent
Non-fluent aphasias are impaired in their ability to articulate. Unlike some fluent aphasias, non-fluent aphasics retain a relatively intake auditory verbal comprehension. Some examples of non-fluent aphasias include: Broca’s aphasia, Transcortical motor aphasia, and global aphasia. [5]
  • Pure-Aphasia
Pure aphasias display themselves as selective deficits to writing, reading or the recognition of words altogether. Pure aphasias include: Pure alexia, Pure word deafness, and Agraphia. [5]


Types of AphasiaEdit

Broca's AphasiaEdit

Broca's aphasia, also referred to as 'expressive aphasia, occurs as a result of damage to the frontal lobe of the brain. As a result of the deletion of function words (i.e. 'and', 'the'), speech by a Broca's aphasic appears telegraphically. As opposed to wernicke's aphasia, speech is nonfluent, and highly laboured depending upon the severity of the aphasia. [1]

Global AphasiaEdit

This type of aphasia is a result of extensive damage to the language areas of the brain with the impairments appearing globally across all areas of speech processing and production. [1]

Transcortical Motor Aphasia (TMA)Edit

Patients with TMA, also referred to as adynamic aphasia, display nonfluent speech as well as phonemic and global paraphasias and the omission of function words. This aphasia results from damage, typically caused by a stroke, of the anterior superior frontal lobe. [1]

Wernicke's AphasiaEdit

Wernicke’s Aphasia occurs as a result of damage to the temporal lobe of the brain. Patients exhibit fluent speech and paraphasias and in some types are unable to comprehend speech as well as produce comprehensible speech. [1]

Conduction AphasiaEdit

Conduction aphasia, also referred to as 'associative aphasia', is a fluent disorder caused by damage to the left hemisphere of the brain above and below the posterior sylvian fissure. Auditory comprehension remains fairly intact in these individuals, with speech production being mostly affected. Speech repetition is poor, and spontaneous speech production is laboured, with frequent substitution of words or transposing of sounds. As opposed to wernicke's aphasia, patients with conduction aphasia are often aware of their mistakes and make efforts at correcting their errors. [6] [1]

Anomic AphasiaEdit

Anomic aphasia occurs as a result of damage to the language areas outside the perisylvian circle. Characteristic of this aphasia is difficulty in word retrieval, while fluent and well-articulated speech remains intact. [1]

Transcortical Sensory Aphasia (TSA)Edit

TSA patients display damage to the temporal occipital parietal junction located behind Wernicke's area. [6]

TSA differs from Wernicke's aphasia in that, although they are both fluent disorders, TSA sufferers have fluent and usually comprehensible speech, save for semantic paraphasia in which similar words are substituted for an item. Auditory comprehension is often severely impaired. [1]


  • The following table separates the different types of aphasias, identifies the area of the brain affected and then names the deficits incurred by each.
Disorder Site of Lesion Spontaneous Speech Speech Comprehension Repetition Naming
Broca’s aphasia Left frontal cortex rostral to base of motor cortex Nonfluent Relatively intact Poor Poor
Global aphasia Anterior and posterior language areas Nonfluent Poor Poor Poor
Transcortical motor aphasia Areas anterior and superior to Broca’s areas Nonfluent Relatively intact Intact Poor
Wernicke’s aphasia Posterior part of the superior and middle left temporal gyrus and left temporoparietal cortex Fluent Poor Poor Poor
Conduction Aphasia Temporoparietal region, above and below posterior Sylvian fissure Fluent Relatively intact Poor Intact
Anomic Aphasia Posterior part of the superior and middle left temporal gyrus and left temporoparietal Fluent Relatively intact Intact Poor
Transcortical sensory aphasia Posterior to Wernicke’s area around boundary of occipital lobe Fluent Poor Intact Poor

(From Biological Psychology by Klein, Stephen B., © 2000.) [3]

Signs and SymptomsEdit

Individuals may experience one or many of the following symptoms of an acquired aphasia due to stroke or brain damage:


  • Disturbances in Naming 'Paraphasia' :

Paraphasia refers to the inability to use correct words in speech through substitution of other words in a way that makes speech incomprehensible. In normal human speech, the ability to quickly retrieve words from a mental lexicon makes it easy for speech to sound fluid, well- structured and effortless. This process of selecting a word, termed ‘word finding’, is automatic for most of the population of normal speakers, but for aphasics displaying paraphasia, this process is greatly impaired resulting in the substitution of random words for the intended word. It is called ‘global’ aphasia when an aphasic substitutes an entire word and ‘semantic’ aphasia when a word belonging to the same semantic field is substituted. [1]


  • Disturbance of Fluency:

Aphasic patients are grouped into two categories: fluent, and non-fluent. Fluent aphasics retain the ability to speak in continuous strains of words, with the meaning of the uttered words being the point of issue. Non-fluent aphasics, such as Broca’s aphasics, suffer from low speech rate, short sentence length, with the production of sentences, and even single words being laboured. [1]


  • Disturbance of Repetition:

In some aphasia patients, the ability to repeat words may be lost. More specifically, impairment of the ability to repeat indicates that the damage to the brain is located in the perisylvian region of the dominant hemisphere. Conversely, patients suffering from transcortical aphasia repeat too frequently, and engage in a echolalia, meaning they repeat what is being said to them without knowledge that they are doing so. [1]


  • Disturbance of Grammatical Processing 'Agrammatism' :

Agrammatism refer to an aphasic’s inability to speak correctly in terms of grammatical morphemes. As a result of this, free grammatical morphemes, as well as inflectional affixes which indicate tense or aspect, are not present in speech. Sentences are oversimplified with the omission of these function words, resulting in a telegraphic speech. Also, these patients have difficulty with questions or complex sentence, such as passive sentences. The severity of the aphasia predicts the amount of errors an aphasic makes in this area. [1]


  • Disturbances of Reading and Writing:

Certain Aphasias can affect reading and/or writing as well as speech production and processing. Reading and writing are not necessarily affected together or even equally when the pairing does occur, however, in some aphasias, all of the above are affected together, only in varying degrees of intensity. [1]


  • Apraxia of Speech:

This type of Apraxia, also referred to as dyspraxia, occurs when the brain is damaged in a way that disrupts voluntary movement involved in speech production. When patients with Apraxia are asked to perform a physical command, they are unable to do so even though the command is understood and the speech muscles are not impaired due to paralysis. Two types of Apraxia exist: Acquired Apraxia of Speech, and Developmental Apraxia of Speech. The focus, as it related to Aphasia, is in acquired apraxia of speech as it is a result of sustaining injury to the central nervous system. [1]


TreatmentsEdit

Learning ExerciseEdit

1. The following youtube clips show different situations in which people suffer from aphasia. During the first segment, you encounter councilman Ken Albrecht. Given the way he speaks during therapy, what type of Aphasia does he likely have? As well, referring back to the table on the types of aphasia, what type of Aphasia does the man in the second clip suffer from?

http://www.youtube.com/watch?v=Bk13HLma2CI

http://www.youtube.com/watch?v=ZDbSh5DoVJA&feature=related

2.Refer back to the readings of this chapter. What is the primary issue with the Geschwind model?

3.Watch the following video: http://www.youtube.com/watch?v=NUTpel04Nkc

  • What qualities of Broca’s aphasia does Charles display?
  • Why is it that he has such an issue with the simple sentence concerning the leopard and the lion?
  • What types of symptoms would you be witnessing if Charles was suffering from Conduction Aphasia?

4. What does the study of Aphasias tell us about the brain and language?

5. What recent advancements have made it possible to study the brain in detail?

6. As a doctor you encounter a patient who begins to describe experiencing what you suspect to be a stroke. Upon studying their behaviour, you come to find that their fluency of speech is normal, but their ability to name things is greatly impaired and proves to be laboured and frustrating for the patient. What type of aphasia has this patient experienced? What part of the brain was likely damaged due to the stroke?

7. If the temporoparietal region of the brain is damaged, what type of aphasia is a patient suffering from and what would their symptoms be?

ReferencesEdit

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 Damasio, A. R. (1998). Signs of aphasia. In M. T. Sarno (Ed.), Acquired aphasia (3rd ed.). (pp. 25-41). San Diego, CA US: Academic Press. doi:10.1016/B978-012619322-0/50005-1
  2. 2.0 2.1 2.2 Nadeau, S. E. (. )., Gonzalez Rothi, Leslie Janine (Ed.), & Crosson, B. (. ). (2000). In Crosson B. (Ed.), Aphasia and lanaguage: Theory to practice. New York, NY US: Guilford Press.
  3. 3.0 3.1 Jay, Timothy B. (2003). The Psychology of Language. Upper Saddle River, New Jersey US: Prentice Hall.
  4. Piras, F., & Marangolo, P. (2007). Noun-verb naming in aphasia: A voxel-based lesion-symptom mapping study. NeuroReport: For Rapid Communication of Neuroscience Research, 18(14), 1455-1458. doi:10.1097/WNR.0b013e3282ef6fc9
  5. 5.0 5.1 5.2 Tesak, J., & Code, C. (2008). Milestones in the history of aphasia: Theories and protagonists. New York, NY US: Psychology Press.
  6. 6.0 6.1 http://www.nidcd.nih.gov/health/voice/aphasia.html

Autism and LanguageEdit

Autism Spectrum Disorder

Autism Spectrum Disorder encompasses five neurobiological disorders in which there is a marked impairment in social and communication abilities. Included in this grouping are: Autistic Disorder, Asperger’s Disorder, Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), Childhood Disintegrative Disorder and Rett’s Disorder. Each of these disorders begin in childhood and results in an atypical development which impairs several areas of the child’s functioning. Each case of ASD is different from the next, with degrees varying from mild to severely impaired. Language abilities are affected by varying degree of ASD, with the exception of those suffering from Aspergers. Individuals with the higher functioning ASD retain their linguistic as well as proper cognitive development. Although the research poured into understanding ASD has been substantial, our understanding of the disorder and how it truly functions largely remain a mystery.


Autism

The word Autism means “autos” and “self” in Greek, which refers to how individuals with autism seem to exist in a world of their own, often times unable to communicate and interact with others. Autism is highly variable in nature. The disorder first appears in childhood, with a diagnosis usually occurring by two or three years of age. A triad of symptoms must be present for the child to be classified as autistic, and they include; impairments in social interaction, restricted interests/repetitive behaviour, and lastly, impairments in communication. While not all individuals with autism suffer from language impairments, the majority do, with varying degrees of severity existing among the autistic population. As well, many aspects of language abilities are affected by varying degree of autism, as well as non-verbal communication methods such as gesturing, normal facial expression and eye contact with other individuals.


Autism and Language

Language impairments in individuals with Autism often present itself early in life with delayed onset of babbling and diminished responsiveness; however, not every child with autism will have issues concerning language. Typically, as the child grows older, communication becomes further impaired as the individual with autism are less likely to communicate with their caregivers and other children. Some autistic individuals are incapable of speech entirely, while others are able to speak rather normally. Often, autistic communication presents itself in echolalia in which the autistic individual repeats another person’s words, or reverses their pronouns. Two forms of echolalia exist: Immediate echolalia refers to the immediate repetition of a word, whereas delayed echolalia results in the repetition of a phrase or word after a delay. Research also suggests that autistic children may have difficulty in developing symbols in language, further impairing their language abilities. The autistic’s difficulty in relating to others impairs their language in speaking with others. Meaning, rhythm, bodily language and the nuances of vocal tones are all area of speech in which autistics may have varying levels of difficulty.


Patterns of Language


Repetitive or rigid language: Individuals with autism will often speak words or phrases that have little contextual meaning to the conversation, or will repeat words heard by other people during conversation, called echolalia. Echolalia may also occur after watching television programs in which the child repeats portions of the dialogue. Some autistic individuals may also speak with a high pitched voice.


Intense focus on a single subject: Some individuals with autism may hold intense interest about a single subject or event in which they prefer to revisit through conversation with others Difficulty with non-verbal language: Because of the nature of autism, people sufferings from it are often unable to properly use gestures which add to conversational speech. They lack eye contact, and the normal interactive social nuances which often time leads the autistic individual to act in frustration with inappropriate behaviour or unusual vocal outbursts.


Fragmented language development: Autistic individuals who are fortunate to develop language abilities often develop them at an abnormal rate. While one area may be highly developed, another may be lacking. For example, some children may be able to read by the age of 5, but may have little comprehension about what they have just read.


Therapies and Tools

The primary form of therapy to aid in language development is through a Speech Language Pathologist. An SLP begins by evaluating the child’s speech and language comprehension, then from this evaluation develops a specialized program in order to improve one or many of the language areas affected. Early and intensive intervention is believed to be best by many professionals.


Picture Exchange Communication System (PECS)

  • The PECS is used as a means of alternative communication for autistic individuals. Developed in 1985, PECS was formed to teach functional communication behaviour to children with autism. It acts as a way for those with autism to initiate conversation through the indication of a picture associated with the desired action or object. Small thumbnail pictures depict the actions and/or objects that the individual uses or does in everday life. The picture to the right contains functional pictures such as "boots", "jacket", and the action of "washing hands" that a person with autism may select and hand to their caregiver in order to indicate that they would like their boots, jacket or want to wash their hands.


Speech Generating Devices (SGD)

  • Speech Generating Devices are systems that enable nonverbal individuals to communicate via software installed on PCs, PDAs or other electronic devices. The device can have a speech output in which the words entered are said electronically, allowing for these nonverbal individuals to actively participate in society. One study suggested that 86% of studies concerning the positive effects of SGD were evident, giving credibility to SGD as a viable option for communicating with individuals with autism.


  • Every so often, an underestimated autistic individual surfaces and changes the way in which the world views the mysterious world of autism. One such person is Carly Fleischmann who has astounded professionals upon learning to use a computer to communicate with the outside world- exposing a hidden intellect. To read more about Carly's breakthrough story, visit http://carlysvoice.com/


References

1. Butz, J. (2009). Speech therapy. In E. A. Boutot, M. Tincani, E. A. Boutot & M. Tincani (Eds.), Autism encyclopedia: The complete guide to autism spectrum disorders. (pp. 65-69). Waco, TX US: Prufrock Press.

2. Charlop-Christy, M., Carpenter, M., Le, L., LeBlanc, L. A., & Kellet, K. (2002). Using the picture exchange communication system (PECS) with children with autism: Assessment of PECS acquisition, speech, social-communicative behavior, and problem behavior. Journal of Applied Behavior Analysis, 35(3), 213-231.

3. Jurgens, A., Anderson, A., & Moore, D. W. (2009). The effect of teaching PECS to a child with autism on verbal behaviour, play, and social functioning. Behaviour Change, 26(1), 66-81.

4. Sloman, G. M. (2011). Training paraprofessionals to implement the picture exchange communication system (PECS). ProQuest Information & Learning). Dissertation Abstracts International Section A: Humanities and Social Sciences, 71 (8-)

5. van, d. M., & Rispoli, M. (2010). Communication interventions involving speech-generating devices for children with autism: A review of the literature. Developmental Neurorehabilitation, 13(4), 294-306.

6. http://www.nidcd.nih.gov/health/voice/autism.asp