7.2 language disorders

7.2 language disorders

Agraphia → language disorder related to

• in speech

• in writing

Alexia → language disorder related to

• in reading

Aphasia does NOT include language difficulties that are explained only by

• Loss of sensory input, especially vision & hearing

• Motor paralysis or incoordination of mouth (anarthria) or hand (for writing apraxia)

Aphasia → three categories

• Fluent Aphasia

• Nonfluent Aphasia

• Pure Aphasia

Fluent Aphasia

• fluent speech but difficulties in auditory verbal comprehension

• impairment in input or reception of language

• A type: Wernicke’s Aphasia → or sensory aphasia

Wernicke’s Aphasia, or Sensory Aphasia

• Deficits in classifying sounds or comprehending words into coherent speech.

• Production intact → they can speak easily & produce long sentences /the problem is to understand language, sounds & meaning

• Hearing & making sense of speech sound demands the ability to qualify sound

• Typical patient characteristic → Word salad

• Patients confuses phonetic characteristics

• Writing difficulties due to inability to discern phonemic characteristics

Wernicke’s Aphasia, or Sensory Aphasia → typical types of errors which appears in patients

• Neologism → inventing a word that doesn't exist, e.g., “I need my flinder”

• Semantic paraphasias → replacing the intended word with a different, often semantically related, word, e.g., Wants to say “dog” → says “cat.”

• Poor repetition → not able to repeat a word accurately

word salad

• intelligible words strung together randomly → patient may speak fluently, but the content is difficult or impossible to understand

• Neologism

• inventing a word that doesn't exist.

Wernicke’s aphasias can turn into 

• TSA = transcortical sensory aphasia →

  • the repetition is preserved

Transcortical Sensory Aphasia (TSA)

• isolation syndrome

• Ability to repeat & name objects.

• Fluent speech although not logical, without articulatory disorders but not spontaneously.

• Cannot comprehend words even though they can repeat them.

Conduction Aphasia

• Ability to speak, name objects, & understand speech but cannot repeat words.

• Disconnection between “perceptual word image” & motor systems producing the words.

Anomic Aphasia or Amnesic Aphasia

• Ability to comprehend speech, produce meaningful speech, & can repeat speech

• Great difficulty naming objects

Nonfluent Aphasia

• difficulties in articulating

• A person continues to understand speech but has to labour to produce it.

Types of nonfluent aphasias

• Broca’s Aphasia or expressive aphasia

• Transcortical Motor Aphasia (TMA)

• Global Aphasias

Broca’s Aphasia or expressive aphasia → characteristics of patients affected

• Ability to understand speech

• Labors hard to produce speech & speaks in short phrases interspersed with pauses

• Makessound error, repetitious error in grammar & frequently omits function words.

• Can be mild or severe

• Can start being one in an acute moment & can turn into a Transcortical Motor Aphasia

Transcortical Motor Aphasia (TMA)

• Good repetition

• Poor spontaneous production

Global Aphasias

• Labored speech

• Poor comprehension

 Pure Aphasia

• selective impairments in reading, writing, or recognizing words.

Geschwind´s model describes the

• main neuronal pathways involved in language comprehension & production

• how different types of aphasia occur when specific areas or connections are damaged

Key take away from Geschwind´s model

• aphasia results from damage to specific language areas or connections within the network

• each type of aphasia reflects the disruption of a particular step in the pathway from listening to understanding & producing words

NEURAL LANGUAGE NETWORK → Geschwind´s model

• Conceptual center (ideas & meaning)

• Motor center of words (Brocas area)

• Auditory center of words (Wernicke’s area)

• Arcuate fasciculus (connects comprehension & production areas)

• Verbal output (Articulation)

• Verbal input (Auditory)

• Conceptual center (ideas & meaning)

• Elaborates & integrates concepts

Motor center of words (Brocas area)

• Plans & programs the motor sequence for speech production.

Auditory center of words (Wernicke’s area)

• Perceives & analyzes the spoken words.

Arcuate fasciculus (connects comprehension & production areas)

• Essential for repetition & verbal integration.

Verbal output (Articulation)

• Executes the motor program to produce speech.

Verbal input (Auditory)

• Receives & transmits auditory information from spoken words.

Why Broca’s aphasia (non-fluent/expressive aphasia) appears according to Geschwind´s model

• Lesion in the motor center of words (Broca’s area).

• Impairs planning & programming of speech production, resulting in non-fluent, effortful speech.

Why Wernicke’s aphasia (fluent/receptive aphasia) appears according to Geschwind´s model

• Lesion in the auditory center of words (Wernicke’s area).

• Impairs comprehension & analysis of spoken words, resulting in fluent but meaningless speech.

Why Conduction aphasia appears according to Geschwind´s model

• Lesion in the arcuate fasciculus.

• Disrupts the connection between comprehension & production areas, leading to impaired repetition with relatively fluent speech & good comprehension.

Why Transcortical motor aphasia (TMA) appears according to Geschwind´s model

• Lesion between the conceptual center & the motor center of words.

• Disconnects ideas/meaning from speech production, resulting in non-fluent speech with preserved repetition.

Why Anarthria (pure motor speech disorder) appears according to Geschwind´s model

• Lesion between the motor center of words & verbal output.

• Impairs the execution of the motor program for speech (articulation), resulting in severe speech production difficulties (not a true aphasia, as language formulation is intact).

Why Transcortical sensory aphasia (TSA) appears according to Geschwind´s model

• Lesion between the conceptual center & the auditory center of words.

• Disconnects meaning from auditory input, resulting in fluent speech with poor comprehension but preserved repetition.

Why Pure word deafness (auditory verbal agnosia) appears according to Geschwind´s model

• Lesion between verbal input and the auditory center of words.

• Impairs the transmission of auditory information to language areas, resulting in inability to understand spoken language despite normal hearing.

Aphasia results from

• damage to specific ares or connections with the language network

• each type of aphasia reflects the disruption of a particular step in the pathway from understanding to producing words

Fluent aphasias

• speech is fluent & well-articulated, but there are problems with comprehension &/ or word retrieval

  • anomic aphasia

  • conduction aphasia

  • transcortical sensory aphasia

  • Wernicke´s aphasia

Nonfluent aphasias

• speech is slow, effortful & nonfluent, with no problems in production

  • Transcortical motor aphasia

  • Broca´s aphasia

  • Mixed transcortical aphasia

  • Global aphasia