Brain Injury Glossary
Understanding brain injury terminology can feel overwhelming, especially when symptoms are subtle or unfamiliar. This glossary provides medically accurate definitions alongside simple explanations to make neurological concepts easier to understand.
This glossary supports the Brain Injury 101 series and explains common neurological symptoms including memory problems, cognitive fatigue, emotional regulation changes, sensory sensitivity, executive dysfunction, and anosognosia.
Browse by letter
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B |
C |
D |
E |
F |
I |
L |
M |
N |
P |
R |
S |
T
A
Amygdala
Medical definition:
Structure deep within the brain involved in emotional processing, fear response, and threat detection.
Plain language:
Part of the brain’s alarm system.
Why this matters:
Changes may affect emotional reactions and stress responses.
Anosognosia
Medical definition:
Neurological condition in which a person lacks awareness of their own impairment due to dysfunction in brain regions responsible for self-awareness.
Plain language:
The brain cannot recognize that it is injured.
Why this matters:
May affect treatment decisions and safety awareness.
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Anterior Cingulate Cortex
Medical definition:
Brain region involved in emotional regulation, attention, and decision-making.
Plain language:
Helps manage emotions and focus.
Autonomic Dysfunction
Medical definition:
Impaired regulation of involuntary body functions including heart rate, blood pressure, and temperature control.
Plain language:
The body’s automatic systems may not regulate normally.
Atypical Parkinsonism
Group of neurological disorders causing movement symptoms similar to Parkinson’s disease but with different progression patterns.
B
Brain Fog
Medical definition:
Subjective cognitive symptoms including slowed thinking, reduced mental clarity, and impaired concentration.
Plain language:
Thinking feels cloudy or slow.
Why this matters:
May affect work, memory, and daily functioning.
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C
Caregiver Burden
Emotional, physical, and financial strain experienced while caring for someone with chronic illness or neurological injury.
Chronic Traumatic Encephalopathy (CTE)
Medical definition:
Progressive neurodegenerative condition associated with repeated head impacts and abnormal accumulation of tau protein.
Plain language:
Brain condition linked to repeated hits to the head over time.
Cognitive Decline
Gradual reduction in thinking abilities such as memory, reasoning, and attention.
Cognitive Fatigue
Mental exhaustion caused by increased neurological effort required for thinking after brain injury.
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Cognitive Overload
Occurs when incoming information exceeds the brain’s reduced processing capacity.
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Corticobasal Degeneration
Rare neurodegenerative disorder affecting movement and thinking ability.
D
Decision Fatigue
Reduced ability to make decisions after prolonged cognitive effort.
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Disinhibition
Reduced ability to suppress impulsive responses due to frontal lobe disruption.
Dysphagia
Difficulty swallowing caused by neurological impairment.
E
Emotional Dysregulation
Difficulty managing emotional responses due to neurological changes.
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Energy Envelope Theory
Framework describing how individuals function best when activity stays within available cognitive energy limits.
Executive Dysfunction
Impairment in planning, organization, and task completion.
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F
Functional Neurological Disorder (FND)
Neurological condition involving disruption of brain network functioning without structural damage visible on imaging.
Frontotemporal Dementia
Neurodegenerative condition affecting personality, judgment, and language.
I
Impulse Control
Ability to pause before acting or speaking.
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Irritability
Increased sensitivity to stress due to neurological changes.
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L
Lewy Body Dementia
Neurodegenerative disorder associated with abnormal protein deposits affecting cognition and movement.
M
Memory Impairment
Reduced ability to store or recall information.
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Mild Traumatic Brain Injury (mTBI)
Medical classification often including concussion.
N
Neurodegeneration
Gradual loss of brain cell function over time.
Neuroinflammation
Inflammatory response occurring within the brain after injury.
Neuroplasticity
The brain’s ability to form new neural connections after injury.
P
Parkinsonism
Group of movement symptoms including tremor, slowed movement, and stiffness.
Post-Concussive Syndrome
Persistent symptoms lasting weeks or months after concussion.
Prefrontal Cortex
Brain region responsible for decision-making and impulse control.
Processing Speed
Rate at which the brain interprets information.
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R
Reduced Stress Tolerance
Reduced ability to manage cognitive or emotional demands.
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Repetitive Head Impacts
Multiple blows or jolts to the head occurring over time.
S
Sensory Overload
Incoming sensory input exceeds the brain’s processing capacity.
Sensory Sensitivity
Increased neurological response to sensory input.
Social Masking
Effort used to hide cognitive symptoms in social settings.
Subconcussive Impacts
Head impacts that do not cause obvious concussion symptoms but may contribute to long-term neurological changes.
T
Tau Protein
Protein that can accumulate abnormally in certain neurodegenerative conditions including CTE.
Tauopathy
Group of neurological diseases involving abnormal tau protein accumulation.
Traumatic Brain Injury (TBI)
Disruption of normal brain function caused by external force.
Working Memory
Ability to temporarily hold and use information.
