Chap 15: Language 1. What evidence indicates that genes contribute to some aspec

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Question

Chap 15: Language 1. What evidence indicates that genes contribute to some aspects of language? 2. Describe the cause and symptoms of Williams syndrome 3. ldentify the symptoms and causes of these type of aphasia 4. Specifically, what are the effects of damage to Broca's area? To 5. Describe the symptoms of deep dyslexia, and the symptoms of 6. What is the "TMS temporary-lesion approach?" What advantages 7. In Sperry's study of split-brain patients, a patient could report (language disorders): paraphasia, agraphia, alexia, apraxia, and global aphasia Wernicke's area? surface dyslexia. Provide examples does this research tool offer? words projected to the left-hemisphere, but not the right hemisphere. Describe what a "split-brain" is, and the resulting deficit 8. Explain the "right-ear" advantage, and why it exists 9. Describe prosopagnosia. 10. How do the Wada test and split-brain studies identify which areas of the brain are involved in prosopagnosia? 11. Explain how each of the following factors can influence recovery of function: type of rehabilitation, age, lesion momentum, trauma versus stroke damage. 12. Describe "constraint-induced movement therapy."

Explanation / Answer

q.1 There is a large literature examining the relationship between different components of the developing language system, both at the species-universal and the individual differences levels of analysis. There is also a growing literature examining the genetic and environmental etiology of different language skills and difficulties (e.g. Stromswold, 2001). However, there is relatively little research that focuses explicitly on the etiology of the relationships between different components of language. One recent example of such a study examined the relationship between lexical and syntactic growth in 2 and 3 year olds, using data from a parental checklist of words and syntactic structures produced by the child (an adaptation of the McArthur-Bates Communicative Developmental Inventory, Dale, Reznick, & Thal, 1998; Fenson et al., 1994). There were strong genetic correlations between vocabulary and grammar at 2 and 3 years of age, indicating that many of the genes influencing individual differences in these two skills are shared. Similarly, strong shared environmental correlations indicated that many of the environments influencing vocabulary and grammar are shared.

q.2

Williams syndrome (WS) is a genetic condition that is present at birth and can affect anyone. It is characterized by medical problems, including cardiovascular disease, developmental delays, and learning challenges. These often occur side by side with striking verbal abilities, highly social personalities and an affinity for music.

Williams syndrome is caused by the spontaneous deletion of 26-28 genes on chromosome #7. The deletion occurs in either the egg or the sperm used to form the child with Williams syndrome. Accordingly, the deletion is present at the time of conception. It is likely that the elastin gene deletion accounts for many of the physical features of Williams syndrome. Some medical and developmental problems are probably caused by deletions of additional genetic material near the elastin gene on chromosome #7. The extent of these deletions may vary among individuals. In most families, the child with Williams syndrome is the only one to have the condition in his or her entire extended family. However, the individual with Williams syndrome has a 50% chance of passing the disorder on to each of his or her children.

COMMON FEATURES OF WILLIAMS SYNDROME INCLUDE:

CHARACTERISTIC FACIAL APPEARANCE

Most young children with Williams syndrome are described as having similar facial features. These features include a small upturned nose, long philtrum (upper lip length), wide mouth, full lips, small chin, and puffiness around the eyes. Blue and green-eyed children with Williams syndrome can have a prominent "starburst" or white lacy pattern on their iris. Facial features become more apparent with age.

HEART AND BLOOD VESSEL PROBLEMS

The majority of individuals with Williams syndrome have some type of heart or blood vessel problem. Typically, there is narrowing in the aorta producing supravalvular aortic stenosis (SVAS), or narrowing in the pulmonary arteries. There is a broad range in the degree of narrowing, ranging from trivial to severe (requiring surgical correction of the defect). Since there is an increased risk for development of blood vessel narrowing or high blood pressure over time, periodic monitoring of cardiac status is necessary.

HYPERCALCEMIA (ELEVATED BLOOD CALCIUM LEVELS)

Some young children with Williams syndrome have elevations in their blood calcium level. The true frequency and cause of this problem is unknown. When hypercalcemia is present, it can cause extreme irritability or "colic-like" symptoms. Occasionally, dietary or medical treatment is needed. In most cases, the problem resolves on its own during childhood, but lifelong abnormality in calcium or Vitamin D metabolism may exist and should be monitored.

LOW BIRTH-WEIGHT / SLOW WEIGHT GAIN

Most children with Williams syndrome have a slightly lower birth-weight than their brothers or sisters. Slow weight gain, especially during the first several years of life, is also a common problem and many children are diagnosed as "failure to thrive". Adult stature is smaller than average

FEEDING DIFFICULTY (GENERALLY LIMITED TO THE EARLY YEARS)

Many infants and young children have feeding problems. These problems have been linked to low muscle tone, severe gag reflex, poor suck/swallow, tactile defensiveness etc. Feeding difficulties tend to resolve as the children get older.

IRRITABILITY (COLIC DURING INFANCY)

Many infants with Williams syndrome have an extended period of colic or irritability. This typically lasts from 4 to 10 months of age, then resolves. Abnormal sleep patterns with delayed acquisition of sleeping through the night may be associated with the colic. Extreme irritability may also be caused by hypercalcemia in some children with WS.

DENTAL ABNORMALITIES

Slightly small, widely spaced teeth are common in children with Williams syndrome. They also may have a variety of abnormalities of occlusion (bite), tooth shape or appearance. Most of these dental changes are readily amenable to orthodontic correction.

KIDNEY ABNORMALITIES

There is a slightly increased frequency of problems with kidney structure and/or function.

HERNIAS

Inguinal (groin) and umbilical hernias are more common in Williams syndrome than in the general population.

HYPERACUSIS (SENSITIVE HEARING)

Children with Williams syndrome often have more sensitive hearing than other children; certain frequencies or noise levels can be painful and/or startling to the individual. This condition often improves with age.

MUSCULOSKELETAL PROBLEMS

Young children with Williams syndrome often have low muscle tone and joint laxity. As the children get older, joint stiffness (contractures) may develop. Physical therapy is very helpful in improving muscle tone, strength and joint range of motion.

OVERLY FRIENDLY (EXCESSIVELY SOCIAL) PERSONALITY

Individuals with Williams syndrome have a very endearing personality. They have a unique strength in their expressive language skills, and are extremely polite. They are typically unafraid of strangers and show a greater interest in contact with adults than with their peers.

DEVELOPMENTAL DELAY, LEARNING CHALLENGES AND ATTENTION DEFICIT DISORDER

Most people with Williams syndrome will have mild to severe learning differences and cognitive challenges. Young children with Williams syndrome often experience developmental delays. Milestones such as walking, talking and toilet training are often achieved somewhat later than is considered normal. Distractibility is a common problem in mid-childhood, which can improve as the children get older.

Older children and adults with Williams syndrome often demonstrate intellectual "strengths and weaknesses." There are some intellectual areas (such as speech, long term memory, and social skills) in which performance is quite strong, while other intellectual areas (such as fine motor and spatial relations) show significant weakness.

q.3 PARAPHASIA

Paraphasias are defined as unintended utterances. In essence, there is a failure of selection at the phonemic level, producing a phonemic (literal) paraphasia (e.g., “I drove home in my lar”) or at a word (lexical) level (e.g., “I drove home in my wagon”), producing a verbal paraphasia (Table 3-3). Paraphasias are said to be neologistic when the unintended word is heavily contaminated with extraneous phonemes and, as a result, contains juxtapositions of sublexical fragments that are not characteristic of the language (phonemic neologisms) and are nonsensical in context

Agraphia

Agraphia may be defined as a loss or impairment of the ability to produce written language, caused by brain dysfunction. Almost without exception, every individual with aphasia shows at least some degree of agraphia, and tests of writing ability can be used as a screening device to detect the presence of aphasia. Caution is necessary, however, because agraphia accompanies many disturbances other than aphasia.13 Abnormalities of constructional skills, visuospatial discrimination, and disturbances of motor skills, such as ataxia, rigidity, spasticity, chorea, myoclonus, and tremor, cause major alterations in the quality of graphic output.

Three variations of agraphia are outlined.13Left frontal (anterior) agraphia is seen in patients with Broca's aphasia, and their written output parallels their verbal output. Words and letters are large and messy with poor spelling, and sentences are devoid of grammatical words (agrammatism). Left parietotemporal (posterior) agraphia is seen in patients with posterior aphasias, and written output parallels their spoken output. Literal and verbal paragraphias as well as empty writing are present. Visuospatial agraphia is most commonly associated with posterior right hemisphere defects causing constructional disturbance. The script is well formed, but there is a tendency for the written line to slant upward and for the left margin to be larger and increasing in size with subsequent lines.

ALEXIA

Alexia is a form of dyslexia caused by a stroke or brain trauma, and it happens on a spectrum, causing problems as minor as difficulty focusing or the inability to read small words to larger issues, like all words suddenly looking like gibberish.

lexia is the term used when someone loses the ability to read or understand words, sentences, or, in some cases, even letters. It is also called visual aphasia or word blindness. This is fairly common after a stroke. It is caused by severe damage to the left side of the brain (the occipital and temporal lobes).

Alexia is a form of dyslexia but dyslexia is developmental, meaning that it does not happen from an occurrence such as a stroke or traumatic brain injury. Alexia is an acquired reading disability as a result of an acquired event such as a stroke. It is most common for alexia to be accompanied by expressive aphasia (the ability to speak in sentences), and agraphia (the ability to write).

All alexia is not the same, however. You may have difficulty with the following:

Recognizing words

Difficulty identifying and reading synonyms

Difficulty with reading despite your ability to sound out pronunciation of words.

Although you can read words, it is too difficult to read for very long.

Blind spots blocking the end of a line or a long word.

Focusing on the left side of the paragraph or page.

Double vision when trying to read.

Reading some words but not others. Of course this makes reading impossible.

A stroke survivor with alexia that can read larger words, but cannot read tiny words such as “it,” “to,” “and,” etc.)

any combination of some of these traits

APRAXIA

Apraxia is a disorder of the brain and nervous system in which a person is unable to perform tasks or movements when asked, even though:

Causes

Apraxia is caused by damage to the brain. When apraxia develops in a person who was previously able to perform the tasks or abilities, it is called acquired apraxia.

The most common causes of acquired apraxia are:

Apraxia may also be seen at birth. Symptoms appear as the child grows and develops. The cause is unknown.

Apraxia of speech is often present along with another speech disorder called aphasia. Depending on the cause of apraxia, a number of other brain or nervous system problems may be present.

GLOBAL APHASIA

Global aphasia is an acquired language disorder involving severe impairments in both comprehension and production.

It is caused by injuries to language-processing areas of the brain, notably Wernicke's and Broca's areas. Most often, the injuries are the result of a large middle-cerebral-artery stroke.

The symptoms of global aphasia reflect processing difficulties in Wernicke's and Broca's areas. These areas would ordinarily assign words and meanings, string words together, and complete other word-based tasks. Thus, the symptoms of global aphasia are impairments in all aspects of word-basedcommunication -- reading, writing, speaking, and understanding speech.

Q.4 There are several areas of the brain that play a critical role in speech and language.

Broca’s (expressive or motor) Aphasia

Damage to a discrete part of the brain in the left frontal lobe (Broca’s area) of the language-dominant hemisphere has been shown to significantly affect the use of spontaneous speech and motor speech control. Words may be uttered very slowly and poorly articulated. Speech may be labored and consist primarily of nouns, verbs or important adjectives. Speech takes on a telegraphic character. People suffering from Broca’s aphasia have great difficulty with repetition and a severe impairment in writing. In some patients, however, the understanding of spoken and written language may be relatively well-preserved. The nonfluent variant of primary progressive aphasia (nfvPPA) is a type of expressive aphasia.

Wernicke’s Aphasia

Damage to the posterior superior areas of the language dominant temporal lobe (often called Wernicke’s area) has been shown to significantly affect speech comprehension. In other words, information is heard through an intact auditory cortex in the anterior temporal lobe, however, when it arrives at the posterior association areas, the information cannot be sufficiently “translated.” In contrast to Broca’s aphasia, the person with Wernicke’s aphasia talks volubly and gestures freely. Speech is produced without effort, and sentences are of normal length. However, the person’s speech is devoid of meaning.

This pattern of receptive aphasia is marked by: