Lecture 7 - Biology & Cognitive Disability Flashcards
What are the 2 branches of cognitive disabilities?
- Genetic/ Pre-birth cognitive disabilities
2 Developmental Cognitive Disabilities
Outline Genetic/ Pre-birth Cognitive disabilities
These are cognitive disabilites caused due to the malformation of the genes you inherit
- this can be caused by things going wrong in the womb, e.g. illness/ viruses
Examples: - Down Syndrome - Fragile X Syndrome - Ceberal palsy - but 1/3 wont have any cognitive defects •You are born with all these
Potentials:
•Tourettes - unclear cause
•Epilepsy - unclear cause that can impact cognitiosn
Outline down syndrome as an example of a cognitive/ pre-birth disability
- Caused by one of your inherited genes doubling - meaning you have a 47th Gene
- 50% chance of passing it on
- 1 in 1000 born every year
- Reduces mortality, to an average age of 47
- Characteristics:
- facial features
- lower IQ
- Delayed in reaching developmental milestones (walking, speech, language etc)
X - is it ethical to find out if your child has it?
What is meant by developmental cognitive disabilities?
- You acquire them later in life, not pre-birth
- If you Develop atypically - youCannot diagnose them until they fail to reach developmental milestones (e.g. walking, speech, language)
Examples:
•ADHD
•Dyspraxia - odd muscle movements, uncontrolled
Potentials:
•ASD - debate about what actually causes it. Is it an ASD gene? No ones found one
- is it parental upbringing/ infantile virus
X - are the causes actually genetics though?
Outline ASD as a developmental cognitive disabiltiy
•It’s on a spectrum ranging from mild to profound
•Symptoms:
- Difficulties with communication (profound might not even be able to talk)
- Repetitive routines, narrow interests, inflexible preferences
•1 in 1000
- more common in males
X - why are numbers increasing, especially with males
- is prevelance increasing
- or are we screening more?
What are the 5 Causes of developmental cognitive disability
Similar to Causes of Broca’s:
- Head injury
- Brain Tumour (younger, healthier are less at risk)
- Stroke (younger, healthier are less at risk)
- Viral infection (unlikely for a young person to get this - could cause Az
- Toxins - drugs, alcohol etc - can kill brain cells
Could lead to problems with: language, reasoning, perception and mental faculties
Outline the first cause of developmental cognitive disabilities: 1. head injury
Head injuries have a wide variation in severity
- Head injury is most common cause of death/ disability in 0-40 year olds
- 0-4 are most common to visit A&E for TBI
- 15-24 are next more common
Can have closed head injury
Outline closed head injury as part of head injuries as a cause for developmental cognitive abilities
Stuff when there is predominantly internal damage - not necessarily any blood or anything
- such as concussion
For instance in a car crash, our brains are in fluid, when we jolt forward - our frontal lobes hit the front of the skull. We then recoil backwards, our occipital lobes then hit the back of the skull
- Causes double damage:
•Vision (Occipital damage)
•Reasoning (Frontal Damage)
individual differences in how we recover from closed head injury/ concussions
- for instance some will recover in weeks/ months, some will take longer
- Depends on the severity of the injury
- also factors like: female, younger, previous concussions - make it longer to recover
Outline A. R. Luria
- the man with a shattered world
Wrote a book called the Man with a shattered world (1987)
- talks about the patient Zasetsky who had shrapnel in his brain - the occipito-parietal lobe, after the Battle of Smolensk
- Luria documented his progression and his symptoms over time and then intensively treated him. Finding that he had:
- Disorientation: couldn’t recognise words, objects, places, directions
- Physically able, but couldn’t move due to his brain damage - i.e. nothing wrong with muscles/ joints
- All but very oldest memories were lost - was unaware he was in a war, and what regiment he was
- Frontal lobes were okay - could reason, problem solve etc. He had consciousness
- he was aware that he couldn’t remember
AFTER 25 YEARS
- Because it was a localised injury, Luria predicted he could use other pathways in the brain to regain the lost functions
- after 25 years of intensive rehabilitation - he regained his memories and his abilities to function as a social person - so much so that he wrote his own autobiography
What was the timeline of Zasetsky - the man with the shattered world
- Initially was completely cognitively disabled
- With rehabilitation he regained functions slowly
- Could eventually write his experiences up into a book
Outline the second cause of developmental cognitive disabilities: Brain Tumours
Two forms: Benign or malign
- Malign (Cancerous) - infiltration of cancer into brain tissue
- Banign (Will stop) - Compresses healthy tissue, pressurises surrounding neurons
- if it grows this can cause lots of problems: painful, and headaches etc
- Can pressurise the meniges - headaches
- Densley packs and compresses neurons to the point where it kills them
- could be pushing them out against the skull
Outline the third cause of developmental cognitive disabilities: Stroke
It is the most common cause of adult acquired disability - can be fatal if not treated quick enough
Strokes = interfer’s with brains blood supply in some way
- starves neurons of oxygen
- without which it will die.
2 Causes:
- Haemorrhage (caused by an aneurism bursting)
- too much blood in the wrong place - Blood clot cuts off blood supply
- too little blood
What are the symptoms of stroke
F.A.S.T - Fatal if not treated fast enough
- Face droops to one side
- Arms - at least one will sag, cannot lift both
- Speech becomes slurred
- Time to call - quicker they get attention the more favourable the consequences
Symptoms & Signs: •Confusion •Unsteadiness •Movement problems •Slurred speech •Emotionality - agitated/ angry
Not always fatal but in top 3 causes of death
- if its so big, nothing you can do, brain cant cope and dies
Outline the first cause of stroke: Haemorrhage
- If there is a weakness in the wall of the artery, it can’t cope with the pressure of the blood - so it balloons out
- but because it’s made from a weakness in the artery, this aneurysm is really thin and could burt - If it does burst, this gets into the brain and the CSF - this stops the neurons chemical communication
- interupts chemical balance between inside and outisde - They cant communicate with anything, including the heart and lungs, so neurons are starved of oxygen and die
Outline the second cause of stroke: Blood clot
If a blood vessel is blocked, it can cause a stroke
THIS IS CALLED: ISCHAEMIA
Blood cannot flow from the heart to the brain, via the common carotid artery
Outline Henry Marsh: Do No Harm
Henry Marsh is a neurosurgeon, and his book: DO No harm (2014) he discuss the difficulty of anuerysm removal surgery - says its very very difficult surgery
- Have to drill into the brain, avoiding arteries, find the aneurysm and clip it
- if it bursts prematurely, its hard to control the bleeding, as the brain swells up
- 1/4 of blood goes to brain so can lose liters of blood in minutes
- if you nick the aneurysm, the same thing can happen
- if you rip it off without removing it safely, causes this
Have to cut off blood supply to aneursym so it shrivels up and falls off
What are the 3 common side effects following a stroke
- Paralysis of one side - might never regain this side
- Memory difficulties - can recover some of these
- Language problems, depends on location and severity of stroke can be:
•Comprehension difficulties: Temporal lobe
•Production difficulties: motor areas
- after rehabilitation can recover some of these difficulties
- articulation may never be as fluid
Outline what is meant by locked-in-syndrome
Occurs when there is such a catastrophic stroke, that a patient only just survives.
They retain the functioning of their vital organs - lungs and heart etc so they can stay alive
- they also often, depending on the stroke, can retain frontal lobe abilities - consciousness and some reasoning, perhaps temporal could be okay too
- They cant move at all apart from one tiny muscle or a finger perhaps
- so they are conscious and can reason, and can try to communicate using this one muscle
But what if they cant move anything, how can we communicate with them and talk to them - check they are alright
Outline the case of Jean-Dominique Bauby
He was an editor of French vogue magazine who suffered a catastrophic stroke whilst driving with his son
- he managed to survive but had locked-in-syndrome
- he lost all ability to move, BUT it turns out his higher cognitive abilities, such as reasoning and consciousness was in tact
- but because he couldn’t move, no one knew this
- until a nurse noticed him blinking at her in a way that seemed purposeful and concious
Developed a way of communicating using eye blinks - blinked for a certain letter - more common letters less blinked
Wrote an auto-biography - turned into a film: The Diving Bell and the Butterfly
- he died the day the film came out
Outline Alzheimers disease as a developmental cognitive disability
- Most common form of dementia - but is fatal
- Cause uncertain - possibly viral
Causes: progressive neuronal damage
- neurons die-> Brain dies-> you die
Other forms of dementia include:
- Wernicke-Korsakoff’s Dementia, Vascular (problem with blood supply), Mixed dementia
Outline both Micro and Macro Neuronal Damage in Alzheimers
Progressive Neuronal Damage occurs at both the Micro and the Macro level:
- Micro level - internal cell disintegration/ tangles
= inside the cell
- Tauopathy - Neurofibrillary tangles
- Each cell has an internal structure - but in Alzheimers these thin rods become tangled - so the cell cannot keep its shape - Macro Level - Amyloid Plaques - ‘Choke cells’
= outside of the cell
- perhaps a virus/ infections causes these foreign objects - a rogue protien that should be there
- these just attach to the cell and choke it to death
ULTIMATELY: the brains structural integrity and neurons are lost - big holes appear in the brain - neurons die, wither and collapse
- ANS keeps going though so the person can survive for a while, it’s just their higher order functions go
What 4 things does Az effect?
Progressive loss of:
- Memory
- Speech
- Motor Coordination (eventually cant move)
- Energy & strenght (body cant cope)
- Higher functions like memory go first
- Confusion and bizzare behaviours, like trying to leave the house
- Body isnt healthy and immune system not as strong, often can cause death via pneumonia etc
What is the prevalence of Az?
At 65%: 1% chance of getting it
By 70-74%: 3% chance of getting it
90+ : 1 in 3 chances (in Europe)
- lifestyle? Viral?
What did Heidi Hamilton (1994) did
Published her book: Conversations with an Alzheimers patient, which tracked Elsie over 13 years, looking at her language development
- identified 10 progressive language decline that developed
what are the 10 language things Hamilton (1994) identified
- Missing words
- Words that don’t mean anything
- Bad format
- Replacement
- Disordered and unspecific sentences
- Neologism & Formulaic Speech
- Loss of comprehension
- Off topic talk
- Interlocutor takes over
- Loss of language
Outline 1. Missing words as part of Hamilton (1994) study
Language decline in Alzheimers starts off with just having a few missing words, and slightly incoherent speech
- Oh….he’s back in a…. just a few… oh a couple….
- Circumlocation: Cant find the right word, so goes round and round looking for the right one
Outline 6. neologism & Formulaic speech
When it is more severe, the patient makes up random/ nonsense words and uses them in their language use - but they are not aware they have made them up
- For instance: they cleb anyway
Formulaic speech: using pre-formed phrases, that likely were learnt early in development, they are often the last things to go as they are so practiced
- e.g. wait a minute, wait a minute
Outline 10. Loss of language
By the latter stages of the disease, all that occurs is a complete loss of language
- doesnt really talk at all, says hmm and smiles but that could be it
