stiff muscles, muscle twitching, weakness as muscles decrease in size, affects ability to speak/move/swallow
What does ALS affect in the brain/nervous system?
death of motor neurons in the motor cortex, brain stem, and spinal cord
Assistive technologies using muscles (Hawking's computer device)
relatively simple (uses muscle movements only not direct brain activity) eye-blink/cheek muscle based device to select characters, some predictive text used
Brain Computer Interfaces (BCIs)
use the brain to control an external device (arm, voice, cursor, etc.)
What are functions of BCIs
assist, augment, or repair sensory/motor functions
uses brain activity to control selection of letters on a screen, uses EEG signal
What does the P300 reflect
stimulus categorization/decision making processes
taking brain signals and trying to guess what stimulus the person saw/heard/felt
How do you use fMRI to decode semantics?
put someone in fMRI scanner, show lots of stimuli (audio or visual), figure out which brain area responds to each semantic category, show new stimuli, try to use the brain activity alone to guess what topics were in the stimuli
How do you use ECoG to decode phonemes?
combine brain signals with a language model (like siri's predictive text) to guess which phonemes the person thought of
Are people "left or right brained"?
No this is a fallacy, however some functions are lateralized (may use one side more than other)
Dichotic listening procedure
Present speech stimuli to the two ears, ask the person to attend to the left/right ear. usually easier to perceive speech sounds from right ear (right ear advantage), since this projects directly to the dominant left hemisphere
developed in 1940s to study how epilepsy spread from one hemisphere to another, currently measures language lateralization
How does wada procedure work?
temporarily shut down one hemisphere of the brain by injecting sodium amobarbital into left or right carotid artery, neuropsychologist evaluates patient's ability to speak
Left hemisphere is usually
Left hemisphere processes the ___ ___ of visual field, the right hemisphere processes the __ __ of visual field
right side, left side (opposites)
What are seizures?
excessive, abnormal, synchronous neural activity in the brain
constrained to one area of the brain
involve the whole brain, not localized to one are
consciousness is not impaired, not convulsing
consciousness is impaired, convulsing
Symptoms of a complex partial seizure
person might appear "spaced out"
focal seizures are often preceded by an aura
ex: "I smell burning rubber" or "my right side is warm"
EEG for focal seizure
spike and wave only in some electrodes (one hemispheres)
EEG for generalized
involve the whole brain and are not localized to one area
How does epilepsy cause language delay?
if epilepsy affects dominant (usually left) hemisphere language areas, children may have difficulty acquiring communication skills at a typical rate
Characterized by seizures and EEG abnormalities in temporal lobe. Children start with normal development but then severe progressive decline ~3/4. Difficulties understanding speech, progress to generalized language disturbance. Nonverbal skills generally unaffected.
What is IAP?
intracarotid ambarbital procedure (aka a wada test)
individuals with epilepsy show
a shift to more bilateral/right sided language, but still most are left dominant
difficulty finding words, using the wrong words, but sentence structure may be intact. speech is slow, hesitant, may use only short phrases or single words
lack of understanding, impaired comprehension, cannot monitor and correct speech, speech may be normal rate, grammar intact, but cannot correct mistakes
nonfluent speech, poor comprehension, limited ability to name objects or repeat words
blood supply to part of brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients
bleeding in the brain
Transient ischemic attack (TIA)
mini-stroke, symptoms resolve within minutes but may be a warning that a stroke will occur soon
Symptoms of a stroke
Primary progressive aphasia and difference from normal aging
decline is more rapid than expected for normal age, cognitive/motoric processes not typically affected by age are noticeably impaired
How is primary progressive aphasia different from strokes
most prominent clinical feature in SFA is difficulty with speech/language
How does PPA affect language?
affects core speech-language processes; syntax, semantics, phonology, orthography, motor speech
global, mixed transcortical, broca's, transcortical motor
Where does the lesion occur for Broca's aphasia?
inferior frontal gyrus
characterized by very compressed speech, tendency to omit function words ("a"), simple phrases, agrammatical
Why is telegraphic speech called this?
because when people sent telegrams, they were charged per word
nonwords with no relation to the target ("doflur" instead of "shoe")
substitution of phonemes (phonemic paraphasia) or semantically related words (semantic paraphasia) (ex: bap for map)
reading disorder with two subcategories 1. patients cannot recognize single letters or complete words 2. patients cannot read whole words at a glance but must decipher each letter and put the pieces together
Normal milestones in language development
babbling by 10 months
first words by 1 year - 18 months
usually should have intelligible speech by age 4
Signs of developmental disorder
lack of crying, eye gaze, attention, gesture, play, limited vocab
Difficulties for children with receptive language disorders
understanding gestures, following directions, answering questions, pointing, knowing when to take turn
Difficulties for children with expressive language disorders
asking questions, naming objects, using gestures, putting words together into sentences, learning songs and rhymes, using correct pronouns, knowing how to start a conversation and keep it going, changing how they talk in different situations
Specific Language Impairment (SLI) symptoms
Late to talk, struggle with new words/making conversation, difficulty using verbs/correct tense, grammar/syntax, reduced semantic development, reduced vocabulary production/comprehension, difficulty understanding language especially when spoken quickly
SLI is NOT
general slow development, physical abnormalities of speech, autism, acquired brain damage, hearing loss