brain damage and recovery Flashcards
what protects the CNS?
bone (skull and spinal vertebrae)/ blood brain barrier
what can cause damage to the CNS?
injury/disease/ age-related changes
who studies brain damage?
Clinical neuropsychologists/ Physiological psychologists
why study brain damage?
Increases our understanding of normal brain function/ to develop new treatments for brain damage
traumatic brain injury
Brain becomes injured by some external mechanical force/ closed head injury: skull not compromised
contusion
closed head injury, damage to cerebral circulatory system
concussion
Disturbed consciousness but no obvious structural damage
contusion symptoms
- loses consciousness
- memory loss
- problems with coordination
- changes in behaviour/ personality
- trouble with speech or vision
- There are instances where seizure occurs
concussion symptoms
- Loss of consciousness is one of the immediate symptoms of a concussion
- tinnitus
- headaches
- dizziness
- slurred speech
- sensitivity to light
- changes In personality
Diffuse Axonal Brain Injury
Diffuse Axonal Injury (DAI) is a traumatic brain injury
Caused by rapid movement of the brain in the skull
where parts of the brain shift during injury
Diffuse Axonal Brain Injury causes
axons rip apart/ neutrons die due to toxic levels of neurotransmitters released/ severe DAI is clinically characterised by a coma lasting 6+ hours
chronic traumatic encephalopathy
A neurodegenerative disorder arising from multiple blows to the head/ protein called Tau forms clumps that slowly spread throughout the brain, killing brain cells.
tumours
A cancerous mass of cells/ Meningiomas grow between the meninges of the brain
and encapsulates tumours
Meningiomas
Easy to identify on a CT scan / They cause symptoms by applying pressure on surrounding areas
Infiltrating Tumours
not encapsulated and grow diffusely through surrounding tissue
metastatic tumours
tumour that spreads from one area to the other
disease and brain damage
cerebrovascular events such as stroke/ neurodegenerative disorders such as Alzheimers disease, Parkinson’s, other dementias..
stroke
Sudden cerebrovascular events that cause brain damage/ 10,000 cases a year in Irish population: of these, 2,000 will die
types of strokes
Cerebral Haemorrhage (e.g. Aneurysm)/ cerebral ischaemia
Cerebral Haemmorhage (e.g. Aneurysm)
Ruptured blood vessel bleeds into the brain
Cerebral Ischaemia
Disrupted blood flow to an area of the brain/
Thrombosis: clot forms, blocks blood flow
Embolism: Clot travels from a larger vessel
Arteriosclerosis: Thickened artery walls prevent blood travelling
Thrombosis
clot forms, blocks blood flow
embolism
clot travels from a larger vessel
Ischaemic Damage
Once ischaemia begins, it is important to receive treatment FAST/ Can take up to two days for damage to fully stop because of Toxic Glutamate Cascade
Ischaemic Cascade and Treatment
Aspirin can prevent or reduce clotting/ Stroke prevention shown to be more successful than treatment
impacts of stroke, depends on location of penumbra
right hemisphere: left side of body damaged
left hemisphere: right side of body damaged, speech disorders
impact of stroke
amnesia
aphasia - affects 1/3 stroke patients
paralysis
coma
Recovery following Stroke
Age, education level, type and severity of stroke all predict recovery/ individuals who have large language-related white matter tracts in the contralateral hemisphere recover faster
Neurodegenerative Diseases
A range of diseases that affect neurons/ Progressive/ incurable/ result in death or degeneration of neurons
Alzheimer’s Disease
Progressive neurodegenerative disorder/ Cognitive impairment, mostly memory-related
Alzheimer’s Disease progress
gradual – typically patients live 8-10 years following diagnosis
Alzheimer Pathology
- Amyloid plaques
- Neurofibrillary tangles
clumps of protein that clog up the brain causing neuronal death
How do we diagnose Alzheimer’s disease?
Plaques and tangles lead to neurodegeneration – cortical thinning, enlargening of ventricles, loss of volume/ hippocampus especially affected
PET to conform diagnosis of Alzheimer’s disease
Positron emission tomography (PET) can measure amount of amyloid plaque in the brain
The Cognitive Reserve Hypothesis
Stern (2002, 2009): Some individuals are “protected” against AD pathology because of their Cognitive Reserve
How does Cognitive Reserve work?
Greater levels of cognitive stimulation result in more effective use of neural networks despite damage
Cognitive Reserve and Alzheimer’s Disease Progression
AD patients with higher CR remained cognitively intact for longer than those with lower CR despite having same amount of AD pathology (Vemuri et al., 2001)
The Rush Religious Orders Study
- from 1994 to 2011
- Cohort study of nuns and priests who agreed to donate their brains at death
- They had amyloid plaques and neurofibrillary tangles despite not having dementia! (Bennett et al., 2006)
- Can amyloid plaques then be reliably used as a diagnostic for AD?
Neural Degeneration
Progressive cell death
Anterode degeneration
Distal (far) part of neuron dies
Retrograde degeneration
Proximal (near) part of neuron dies
Transneuronal degeneration
Degeneration spread from damaged neurons via synapse to other neurons
Neurodegeneration in disease
Occurs in:
Alzheimer’s disease
Parkinson’s disease
Multiple sclerosis
Schizophrenia
Stroke
Ateophy
Tissue loss
What can Myelin can be damaged by?
Stroke
Inflammation
Immune disorders
Metabolic disorders
Nutritional deficiencies
Poisions
Drugs (ethambutol)
Multiple sclerosis
Condition of central nervous system/ immune attack on myelin causing loss of movement, sensation, feelings of pain and vision
How do we treat nervous system damage?
Blocking neurodegeneration/ promoting CNS regeneration/ rehabilitation
Blocking neurodegeneration
Apoptosis inhibitor protein- prevents further neuronal loss ( rat hippocampus, 1999) / nerve growth factors
the insights gained from studying different of brain damage.
Studying different forms of brain damage provides valuable perspectives on normal brain function.
motor Impairments from stroke
stroke can cause damage to specific areas of the brain responsible for motor control, such as the primary motor cortex, premotor cortex, and supplementary motor area. The disruption of these regions can result in motor impairments, including weakness, paralysis, and difficulties in initiating or coordinating movements. Benjamin et al.’s (2020)
What are the cognitive consequences of Traumatic Brain Injury (TBI) according to Smith et al. (2017)?
Memory impairments, attention deficits, and impacts on executive functions.
How do findings from studying brain damage contribute to understanding normal brain function?
Findings from studying brain damage provide insights into the vital role cognitive functions play in everyday activities and offer a lens to appreciate the normal functioning of the brain.
