Auditory Processing and Language

The angular gyrus plays a role in

reading comprehension by matching words and word sounds (phonemes such as the sound of /ba/) to written symbols of language (graphemes such as b).

Approximately, 50 to 75% of children identified as SLI also develop ...

reading problems (dyslexia) in later years

Wernicke's aphasia is a receptive, fluent aphasia.

This implies reduced comprehension of spoken language with the continued ability to produce speech.

What are the types of aphasia?

Types: Broca's aphasia, Wernicke's aphasia

This area also links A1 to ____________ area which is thought to be contained with the secondary auditory cortex.

Wernicke's

Ear

What is this image?

Brain stem is where you hear things the most NOT

A1

What does SLI look like at different stages of development? Preschool

- Following directions - Delay in developing rules of grammar (irregular forms, tense, number, question forms, pronouns) - Use of language (turn-taking, asking questions, reference, maintaining topic)

What does SLI look like? Early School Years

- Following directions (basic concepts) - Formal grammar - Phoneme grapheme associations - Decoding and blending (rules of phonics)

What does SLI look like? Later School Years and Adulthood

- Higher order language - Decoding - Reading Comprehension - Writing (spelling and formulation of ideas to print).

What does SLI look like at different stages of development? Early Linguistic

- Poor comprehension (understanding words and simple directions) - Delayed language onset (limited vocabulary and slow to combine words)

Broca's area is closely involved in ...

1. fluency of speech 2. grammar 3. syntax In addition to mediating the fluency of speech, Broca's area plays a role in the grammatical and syntactical arrangement of words.

Primary auditory cortex processes The features of sound include;

1. frequency F riends 2. loudness L ike 3. duration D oing 4. change C oke 5. timbre T ogether

Rate Processing Constraint Model Principle 1

1. processing proceeds in a "bottom-up" manner with discrimination of basic acoustic properties supporting language acquisition.

What is aphasia caused by?

Causes: stroke, tumor, brain trauma

Damage to the right hemisphere results in .....

Conversely, right hemisphere damage has the opposite effect: The patient accepts words at face value but loses the nuances of jokes and emotional intention. Impaired harmonic and melodic ability. The ability to appreciate musical tunes may be completely eliminated. Cant understand 80% of nonverbal communication

"I looked through that long pipe thing at the stars" (that is, a telescope). Aphasics may also make phonetic or like-sounding errors, such as "I looked through that telephone at the stars," semantic meaning-related errors, such as "I looked through that barometer at the stars."

Example of something someone with aphasia would say

T/F If articulation is related to a motor impairment of the mouth, tongue, larynx, or pharynx, then it is related to aphasia.

False - it is not related to aphasia. The aphasic impairment is marked by the person's confusion or deficit in choosing the desired sound from all those available in his or her repertoire.

T/F Heschl's area is often smaller in the right hemisphere, sometimes consisting of two gyri to the left's one gyrus.

Heschl's area is often larger in the right hemisphere, sometimes consisting of two gyri to the left's one gyrus.

In order to process speech individuals must hear and respond to transient cues that signal what words are being produced

In everyday language these cues are brief, rapid and successive.

what is anomia aphasia?

In mild cases of anomia, or word-finding difficulties, only a word or two here and there is lost, and the communication can proceed quite normally. In more severe cases, most or all words can be lost.

How does the auditory system differ from the visual system?

In this way, the auditory system differs from the visual system in that each hemisphere receives input from both ears, resulting in bilateral representation of sound.

Wernicke's aphasics usually do not realize their spoken language is meaningless to others (anosognosia for speech).

It is as if they know exactly what is to be communicated, but their delivery is incoherent.

What does having aphasia impair?

It may impair the power to speak, write, read, gesture, or to comprehend spoken, written, or gestured language.

What causes Transcortical Sensory Aphasia?

Lesions in the angular gyrus are the most likely culprits for this aphasia; thus, reading and writing are also affected.

What causes Transcortical Motor Aphasia?

Lesions to the area anterior or superior to Broca's area are associated with this aphasia type.

Wernicke's aphasics, in addition to not understanding what others say, may also not be able to understand what they themselves are saying.

This problem contributes to speaking in the form of a word salad of unconnected words and word sounds. This feature of Wernicke's aphasia is a deficit in putting words together in proper grammatical and syntactical form

T/F One theory of autism considers the idea that autistic people may not be tuned in to the frequency of human speech, but instead have a propensity for lower frequency environmental sounds such as those made by machines.

True

T/F Some bands are more attuned to certain frequencies than others.

True - there is no strict one-to-one correspondence

Damage to Wernickes Area in the left hemisphere results in the partial or total inability to decipher spoken words.

Wernicke's aphasia or Receptive Aphasia BUT they can still decipher emotional tone -- because the speaker's intent, such as anger, sarcasm, or humor, is processed as voice intonation.

Normal vs LLI Subjects on Two Auditory Discrimination Tasks Tallal and colleagues (1985a, 1985b) found impaired RAP in 6 to 8 year old LLI vs. control children in discrimination and identification tasks.

What is this chart showing?

Aphasia:

a disturbance of language usage or comprehension

..some how we all learn language within the first few years of life....

a task we all take for granted" - Charles Yang, 2006, The infinite gift.

Broca's area is primarily involved in ____________ speech and is also closely associated with _________ speech areas in the motor cortex..

expressive motor

In the primary auditory cortex (Heschl's gyrus) sound is

mapped onto "brain space" that is tonotopically arranged.

Right processes non-speech sounds such as...

melody, intonation and referred to as speech prosody.

The right hemisphere may have no speech or understanding of grammatical rules; however, a number of people, and more ________ than ________, have some bilateral representation of speech. Some people, however, have bilateral representation of speech

more women than men

Conduction Aphasia

problem in repeating what others say. In ordinary conversation, expressive speech is fluent but marked with phonemic paraphasias, or errors of word usage of similar-sounding words (such as using the word bark for tarp).

There is strong evidence suggesting that children with SLI differ in their ability to

process "basic sounds" that enter the auditory system in "rapidly succession"

Another problem experienced by many Broca's aphasics is one of articulation

the ability to form phonetic sounds of vowels and consonants, which then are placed in different combinations to form words and sentences

Global Aphasia

the most devastating of the aphasia subtypes because of its profound effect across all areas of speech functioning. There is marked disability in speech production, as well as speech comprehension. Reading, writing, and repetition are also impaired.

Transcortical Motor Aphasia

the patient's halting, nonfluent spontaneous speech; oddly, however, speech becomes fluent if the person merely repeats what another says. Similar to Broca - Speech comprehension is unimpaired and writing may also suffer. Reading comprehension, however, is generally intact.

Damage in Wernicke's aphasia includes

the secondary auditory cortex (Wernicke's area) and some involvement of surrounding structures. These often include the supra- marginal and angular gyri and portions of the middle temporal gyrus.

Rate Processing Constraint Model - Caveat

there is evidence that some children with SLI are impaired in sequencing more slowly presented sounds (Bishop et al., 1999), possibly pointing to a more general deficit in auditory processing.

SLI This classification is applied to children who present with a form of developmental language disorder that can not be attributed

to a known cause such as hearing impairment, mental retardation, childhood schizophrenia, infantile autism, or frank neurological disorders.

Speech understanding, therefore, conveys word analysis, as well as emotional intentions, through ...

tone of voice, pitch, intensity, and rhythm.

Long-latency is

used to assess processing in A1.

These deficits have been reported in adults and children for both _______ stimuli and __________ stimuli

verbal non-verbal

The process of language acquisition is not restricted to the ___ to ____ year period when children actually begin producing words. From birth, infants are predisposed to attend preferentially to the sounds of ___________.

2 to 6 language

Rate Processing Constraint Model Principle 2

2. primary deficit in language impairments may be the inability to integrate and discriminate two or more sensory events which enter the nervous system in rapid succession, in the time window of tens of milliseconds.

Rate Processing Constraint Model Principle 3

3. processing difficulties may be exacerbated if the events are relatively short in the total duration

Humans can detect a wide range of sound from the ____-Hz to the _________-Hz range.

30 20,000

5%-10% So put that number in perspective, that means that while the rate of ASD is currently 1 in 150 children, the rate of SLI is approximately

8 to 11 per 150 children.

Anomic Aphasia

A problem in word finding, or anomia, is the primary, and often only, difficulty in anomic aphasia.

About ___% to _____% of all children beginning school are estimated to have such disorders (Robinson 1987, Tomblin et al. 1997).

About 5% to 10% of all children beginning school are estimated to have such disorders (Robinson 1987, Tomblin et al. 1997).

what parts of the brain are impaired in those with aphasia?

Although cortical damage to the frontal and temporal areas of the left hemisphere causes most aphasias, damage to subcortical tructures of the basal ganglia (specifically the corpus striatum) and the thalamus has also produced aphasia.

How does the ear respond to sound waves?

As the mechanical mechanisms of the middle ear respond to external sound waves, they cause vibrations in the fluid of the inner ear, thus vibrating the hairs of the auditory receptors. These receptors synapse with the auditory nerve.

If a patient is having difficulties processing sound, how can one assess if this is due to a transmission problem in the brainstem?

BAER Finds: Brainstem evoked potentials

What does SLI look like at different stages of development? Prelinguistic

Processing of sounds and syllables Production of sounds and syllables

Transcortical Sensory Aphasia

Severe speech comprehension deficit marks transcortical sensory aphasia. Interestingly, despite being unable to comprehend speech, such aphasics can adequately repeat phrases and sentences presented to them.

However, a subset of children have a protracted and difficult time. These children are said to have "_____________________" (SLI)

Specific Language Impairment - developmental dysphasia.

How does sound enter the ear?

The auditory system contains mechanical receptors designed to detect sound frequency. These hairlike receptors are located in the fluid of the long, coiled, snail-like cochlea of the inner ear.

What is Anomic Aphasia caused by?

This aphasia is a frequent result of widespread brain impairment caused by conditions such as traumatic brain injury and dementias such as Alzheimer's disease.

What is Global Aphasia caused by?

This aphasia is caused by a massive lesion encompassing major portions of the left hemisphere.

The primary auditory cortex of each hemisphere lies deep within the temporal lobe, largely on the medial aspect of the superior temporal gyrus, within the valley of the lateral fissure.

This area is commonly termed Heschl's gyrus and corresponds to Brodmann's area 41.

Wernicke's area lies adjacent to _________ __________ (phoneme - grapheme mapping area) and is connected to ________ area via the a band of fibers known as the arcuate fasciculus (reciprocal interconnection).

angular gyrus Broca's

Deficits in writing are most often associated with lesions to the

angular gyrus, a cortical association area that provides cross- modal integration of visual, tactile, and verbal information.

Wernicke's and Broca's areas are linked by a band of white matter fibers called the ___________ ____________ .

arcuate fasciculus. This allows for close communication between the two areas

Mid-latency evoked potentials

can be used to assess processing in the IC and sometimes the thalamus.

dysarthria or speech apraxia Not like aphasia

caused by paralysis or incoordination of the musculature of the mouth or vocal apparatus

Step 1 The auditory nerve from each ear projects ipsilaterally to the _________ _________ of the medulla

cochlear nuclei

Wernicke's area is responsible for

comprehension

Step 2 From there, each pathway branches to project auditory information to both the ipsilateral and _____________ _________ ___________ nuclei of the medulla.

contralateral superior olivary

The extent of the recovery in aphasia patients largely depends on the

degree of damage.

In the first few weeks after birth, infants can ...

discriminate nearly all the phoneme contrasts (e.g. /pa/ versus /ga/) existing in the human language.

primary auditory cortex This arrangement is - ___________ specific (detection range in humans = 30- 20,000 Hz) - parallels the frequency specific map of the _______

frequency cochlea

Expressive speech links to the __________ __________ (Broca's area), located in the left frontal lobe on the posterior portion of the third frontal gyrus (the inferior frontal gyrus).

frontal operculum

Broca's aphasia most commonly occurs with lesions to the

frontal operculum, but typically also includes lesions to the motor cortex (precentral gyrus or motor strip) and underlying white matter and subcortical structures of the basal ganglia.

Problems with transmission of the signal at any one of these points will result in loss of fidelity of the signal and can cause either _________ or ________ difficulties.

hearing language

The secondary auditory cortex

integrates the features of the sound from the primary auditory cortex.

Individuals with SLI show excessive amounts of ____________ (auditory backward masking) when two auditory stimuli are presented in rapid succession

interference

Auditory system has both ________ as well as _____________ projections (useful for sound localization).

ipsilateral contralateral

Expressive aphasia

is a disorder of speech output. Receptive aphasia implies a difficulty in auditory comprehension.

Fluent aphasia

is characterized by fluent spontaneous speech with normal articulation and rhythm, or fluency in the repetition of words, phrases, or sentences.

Nonfluent aphasia

is difficulty in the flow of articulation, so that speech becomes broken or halting.

Language

is the ability to arrange sounds into infinitely many ways to convey infinitely varied meanings

However, at a very young age (ca 6 months) infants begin to develop phonemic categories ("auditory maps") that correspond to the sounds of their ________ language. This process of "tuning in" to the contrasts present in ones language environment is completed by ....

native the end of the first year

contralateral

opposite side

paragrammatism or extended paraphasia

refers to running speech that is logically incoherent, often sounding like an exotic foreign language.

Most children acquire language

relatively easily and efficiently

tonotopic map

representation in the auditory cortex of different sound frequencies projects onto the auditory cortex, similar to the retinotopic map of the visual system.

semantic rules

rules that govern the meaning of language as opposed to its structure

syntactic rules

rules that govern the ways in which symbols can be arranged as opposed to the meanings of those symbols

ipsilateral

same side

While SLI has traditionally been attributed to delays in the learning of ___________ and ___________ rules critical to development of language (Leonard 1998).

semantic syntactic

Individuals with SLI are selectively impaired in their ability to

separate successive rapid brief sounds of similar frequencies (RAP)

Conduction aphasia is a result of

separation of Broca's area from Wernicke's area by damage of the arcuate fasciculus, the connecting white matter fibers between the two areas.

Left hemisphere is dominant for

speech and the sequences of sounds.

Language is what we use to

tell stories, transmit knowledge, and build social bonds. It comforts, tickles, excites, and destroys.

Step 3 The auditory pathways then course through the lower brainstem and ascend through the ____________, where they are projected to the primary auditory cortex

thalamus