Neuropsychology Flashcards
Alcohol: Acute Effects, Long-term effects, Tolerance, Identification of Problem use
Alcohol:
• It’s widely available, socially acceptable
• Understanding of what is a typical or standard drink
Acute effects: • Slows reaction times • Reduces inhibitions • Sedative • Impairs memory • Slurring of speech • Deterioration of skilled performance
Long-‐term risks/ consequences
• Organ damage (liver/brain); liver metabolizes alcohol
• Development of dependence
Tolerance:
• Continued use produces neuroadaptation
• Larger quantities required to experience drug effects
Identification of problem use:
• Quantity/frequency measure
• Problems experience over lifetime: Michigan Alcoholism Test
- Identification of recent problems: Alcohol Use Disorders Identification Test, AUDIT
- Biochemical markers: Gamma gluteryl transferase (GGT); how your liver is responding to metabolizing the alcohol
Ecstacy: Acute Effects, Long-term effects, Tolerance, Identification of Problem use
- Synthetic drug 3,4-‐ methlyenedioxymethampthetamine (MDMA)
- Street names: XTC, pills, eggs, doves, MDMA
- Illegal use: no quality control, drug substitution
Acute effects:
Euphoria, increased closeness with others
Tongue and cheek chewing, teeth grinding
Nausea and anxiety
Increased body temperature
Ecstasy:
• It is ingested and absorbed in the small intestine
- Short Term: changes brain chemistry, behaviour
- Long Term: changes brain structure, behaviour
- Brain Areas Affected by Ecstasy: neocortex, basal ganglia, hypothalamus amygdala, hippocampus
- Effects serotonin nerve pathways in the Brain: Ecstasy blocks the transporter neuron; there will be an increased level of Serotonin in the presynaptic cleft
- Life threatening Effects (dose dependent): hyperthermia, arrhythmias (irregular heart beat), renal failure (kidney failure)
- Short Term Effects after Ecstasy is gone: During ecstasy there is an increase in the amount of serotonin molecules-‐ elevated mood. After ecstasy there is a depletion of serotonin in the synaptic junction-‐ producing feelings of depression, irritability.
Long Term Effects of Ecstasy: Animal Studies Indicate Neurotoxicity
- BRAIN STRUCTURES
- Brain CHEMISTRY
- Psychological Changes
Brian chemistry changes:
• Serotonin reduced
• Serotonin metabolites
Brain structure changes:
• Serotonin transporters reduced
• Serotonin nerve terminals degenerate (even after multiple years from taking the ecstasy)
Psychological changes
• Ecstasy may damage brain areas controlling memory leading to memory impairment: hippocampus and neocortex
Nulsen on Ecstasy:
Nulsen et al. (2010): working memory was more affected than short term memory in high dosage, long term users. Short memory wasn’t related to ecstasy use.
A brief history of Neuropsychology:
In the early 1800s the dominant view was that the brain worked as a single organ. At this time Franzgall made three assumptions:
- Specific brain areas control particular aspects of mental life
- Brain areas, like muscles, get better as people use them
- As the brain areas grow larger, they create corresponding bumps in the skull that can be studied
- This assumption led to practice of phrenology (determining a persons psychological state by their head shape
• Only the first assumption proved true, but was disregarded because of Gall’s other mistaken assumptions.
Classical Neuropsychological Cases Phineas Gage:
• Railroad worker who sustained an injury when a iron pole went through his scull
• Tamping iron injury 1848
• He lived on surprisingly but resulted in profound personality changes
• Reconstruction of site of injury
Frontal lobe
Reenactment of Phineas Gage case [VIDEO]
- Was initially a balanced, normal man, in charge cause he was able to make rational decisions
- Frontal cortex: assigns priority to messages
- Limbic system and frontal cortex keep thought and process in equilibrium
- After Gages accident his limbic system and the frontal cortex and the link between them is damaged
• He didn’t experience pain: usually the pain messages reach the frontal cortex via the spinal cord and using Substance P at the synapses – must reach a certain threshold to be released
- Pain resisting endorphins diminished the passage of Substance P across the synaptic gap – blocking the pain signals
• How did the severing of his frontal cortex and limbic system (physical changes in the brain) completely change his character?
- The limbic system is free to fire its emotions and behavioral messages without the restraint of the limbic system
- Behaviour becomes unpredictable and erratic: anger, rapid switch between emotions
- He never regained intellectual and emotional self control, balance or sense of judgment
- His communications with humans was less adequate, yet his communications with animals increased
- He died 12 years after the accident
- Areas most seriously damages: both prefrontal cortical areas (mostly left) – connected with areas involved in emotional processing
In 1861 French surgeon Paul Broca encountered a patient named Tan (Leborgne)
• Tans autopsy revealed brain lesions that were linked to Tan’s speech disruption (couldn’t speak except the word ‘Tan’)
• Broca’s discovery (and his respected status) revived support for localization of function.
- Localization of function: the idea that specific psychological function can be affected by damage to specific brain area.
LOCALISATION of SPEECH Production
Tans brain
• Damage was due to an variation in the area related to speech in the frontal cortex (Broca’s area)
Lesion Analysis
• Experimental neuropsychologists look at the results of brain damage to understand the localization of function
• Lesion analysis must address the question of exactly what function has been damaged
- Determine all the abilities needed to complete a task and identify which ones have become dissociated.
What disorder can be caused by brain damage or disjunction?
AMNESTIC DISORDERS
Explain AMNESTIC DISORDERS
Involve memory loss
• ANTEROGRADE amnesia – difficulty forming new long-‐term memories after damage to the hippocampus
• Famous case of patient H.M. has provided a wealth of information:
Regions of the hippocampus were removed to control his epileptic fits
He was unable to learn anything new following the operation: spent the rest of his life in a nursing home.
Many other mental capacities remain in tact
New habits and skills can be learned as a result of new experiences
Other causes of anterograde amnesia include infections, strokes and Alzheimer’s disease
- KORSAKOFF’S Syndrome-‐ damage to the medial dorsal region of the thalamus
- Caused by depletion of thiamine, a result of alcoholism
- It is due to drinking alcohol without eating properly – it occurs very rapidly (one can wake up one morning with no recollection or memory
- Seen as irreversible but patients can recover if the disease is found early
• Result of thiamine deficiency is anterograde amnesia with an additional feature:
- Confabulations: the creation of false memories, which as recalled by the patient as being real
Neuropsychological TESTING (2WAYS)
Two common approaches:
- Individualized assessments:
• Uniquely tailored to a patient
• Allows measurement of specific problems - Standardized test battery:
• Designed to complement each other and comprehensively address psychological functioning
• Carefully prepared and validated
• Examples: Wechsler Audit Intelligence Scale
Both test approaches are often used together to pinpoint where difficulties in the brain lie
Causes of Brain Damage and Dysfunction: STROKE
• Stroke: a loss of blood supply to some part of the brain, resulting in disruption of some aspect of behaviour or mental processes
- Involves little or no pain, often leading to a costly delay in treatment
- Recovery of function is possible, but the extent is dependent on numerous factors:
o Speed of medical treatment
o Where the stroke occurred in the brain
o Health of remaining brain tissue.
Causes of Brain Damage and Dysfunction: TRAUMA
Trauma: an impact on the brain causes by a blow or sudden, violent movement of the head
- Causes the brain to slide within the cerebrospinal fluid and hit the skill
- Amount of damage depends on the force of the trauma
- Damage can be widespread and cause diffuse deficits that are difficult to specify (leads to slowing of information processing.
• Trend of blast-‐Induced Neurotrauma (in soldiers) - Regions of damage: site of impact and region of brain opposite to this.
Causes of Brain Damage and Dysfunction: NEURODEGENERATION: define, examples
• Define: a gradual process of cell damage in the brain usually caused by disease.
• Most prominent neurodegenerative diseases
- Parkinson’s disease, Alzheimer’s disease and Huntington’s disease
o Each effects a particular type of cell, causing them to stop working properly
The famous case study of Tan was undertaken by Paul Broca. His study of Tan identifies the biological underpinnings of language production.
The way a clinical neuropsychological assessment of a new patient would be:
He would start with a standard broad based battery of tests, then move onto specific tests for the patient, based on findings from the initial battery of tests.
The patient HM is a famous case study example of anterograde amnesia, the inability to form new memories.
DISORDERS OF PERCEPTION • Involve impairments in the ability to organize, recognize, interpret and make sense of incoming sensory information “What” and “Where” Visual Pathways • Where system: up the parietal lobe • What system: down the temporal lobe
Explain AGNOSIAS
• Damage to the “what” visual pathways:
Visual agnosia: a condition in which a person no longer knows what objects are based on their appearance
Can still see, describe and draw objects
Can’t be cured so people use other senses as compensatory
E.g. Oliver Sack book: mistook his wife for a hat
• Case Study: Behrmann et al. (1992) Patient Kevin Chapell is unable to recognize objects after an car accident
Sees colours and shapes punctuated by familiar faces
Can’t read words or music anymore
Picks up small components of an object and uses memory and touch to infer what it is
Can sees faces in entirety but not objects as the part that processes faces isn’t damaged
Explain Simultanagnosia
Simultanagnosia
- Damage to the “where” visual pathways
- Simultanagnosia: a condition in which a person can see parts of a visual scene but has difficulty perceiving the whole scene
- Damage or dysfunction on the upper region of the parietal lobes
Explain HEMINEGLECT
Hemineglect:
• Hemineglect: a condition that involves difficulty in seeing, responding to, or acting on information coming from one side of the world.
• May see both sides of the world but are likely to pay attention to one side of the world and ignore the other
• Often occurs after a stroke
• Damage or dysfunction to the parietal lobes
DISORDERS OF LANGUAGE: Broca’s aphasia:
• Broca’s aphasia: loss of fluent speech
Halting and effortful speech
Phonemic paraphasias: words that sound like the words they are trying to say
Tendency to use concrete words only: don’t use connecting words, adjectives, only nouns
DISORDERS OF LANGUAGE: Wernicke’s Aphasia
• Wernicke’s Aphasia: loss of ability to understand written or spoken language and to produce sensible speech:
Fluent and effortless speech that has no meaning
Semantic paraphasias: use a word that means the same as the word you are trying to say
Tendency to use adjectives, adverbs and articles
What happens in RIGHT HEMISPHERE DAMAGE
2) in particular (DISORDERS OF LANGUAGE
- Less common forms of language disorders
- Aprosodia: loss of the ability to use tone of voice to express meaning or to understand other people’s tone of voice
Expressive aprosodia:
o Difficulty expressing tone of voice when speaking
o Able to understand and use cues from other people’s tone of voice
Receptive aprosodia:
o Difficulty understanding the meaning of other peoples tones of voice
o Able to use tone of voice correctly when speaking
Disorders of Language: Stroke
- Sudden damage or death of the cells in a localized area of the brain, due to inadequate blood flow
- Haemorrhage or thrombosis in the main arteries of the brain can cause this oxygen starvation
- Areas of the brain affected by the stroke depend on the particular artery that is affected
• Brain damage caused by strokes tends to be more specific than brain damage caused by a trauma such as a head injury
- Stroke patients may show very specific kinds of neuropsychological deficits, because in strokes only the area in and around a disrupted blood supply is likely to be affected. People with head injuries, in contrast, may display deficits that are far more diffuse, harder to specify, and involve more aspects of functioning, because the damage and disruption caused by the trauma may be more widespread. In short, strokes tend to cause more localized damage, whereas traumas tend to cause more generalized damage.
Disorders of Language: Stroke
- Sudden damage or death of the cells in a localized area of the brain, due to inadequate blood flow
- Haemorrhage or thrombosis in the main arteries of the brain can cause this oxygen starvation
- Areas of the brain affected by the stroke depend on the particular artery that is affected
• Brain damage caused by strokes tends to be more specific than brain damage caused by a trauma such as a head injury
- Stroke patients may show very specific kinds of neuropsychological deficits, because in strokes only the area in and around a disrupted blood supply is likely to be affected. People with head injuries, in contrast, may display deficits that are far more diffuse, harder to specify, and involve more aspects of functioning, because the damage and disruption caused by the trauma may be more widespread. In short, strokes tend to cause more localized damage, whereas traumas tend to cause more generalized damage.
