Pathophysiology of Neurological Disorders and Consciousness

Consciousness

State of being awake and aware.

Arousal

Level of consciousness supported by RAS.

Awareness

Subjective experience of self and environment.

Coma

Unarousable unresponsiveness with absent awareness.

Brain Death

Total loss of brain function, including brain stem.

Cerebral Death

Permanent damage to brain hemispheres; brain stem intact.

Persistent Vegetative State

No awareness; sleep-wake cycles present.

Minimally Conscious State

Inconsistent but reproducible signs of awareness.

Locked-In Syndrome

Full consciousness but unable to move or communicate.

Delirium

Transient disorder of awareness and cognition.

Dementia

Progressive decline in cognitive function.

Alterations in Arousal

Caused by structural, metabolic, or psychogenic disorders.

Extrapyramidal Motor Syndromes

Movement disorders affecting motor control.

Seizure Disorders

Abnormal electrical activity in the brain.

Ischemic Brain Diseases

Reduced blood flow leading to brain damage.

Intracranial Hemorrhage

Bleeding within the skull affecting brain function.

Selective Attention Deficit

Inability to focus on specific stimuli.

Memory Deficits

Impairment in recording, encoding, or retrieval.

Retrograde Amnesia

Difficulty retrieving past events.

Anterograde Amnesia

Difficulty forming new memories.

Agnosia

Defect in pattern recognition across senses.

Dysphasia

Impairment in language comprehension or production.

Broca's Aphasia

Expressive dysphasia due to left hemisphere damage.

Wernicke's Aphasia

Receptive dysphasia with fluent but nonsensical speech.

Anomic Aphasia

Difficulty naming objects or finding words.

Conductive Dysphasia

Difficulty with verbatim repetition of phrases.

Acute Confusional State

Sudden onset of altered awareness and cognition.

Delirium Clinical Presentation

Includes difficulty concentrating, restlessness, and irritability.

Mild Cognitive Impairment

Intermediate state between normal cognition and dementia.

Neurodegenerative conditions

Irreversible disorders affecting neuronal function.

Alzheimer disease (AD)

Most common cause of dementia, affects memory.

Dementia with Lewy bodies (DLB)

Dementia characterized by abnormal protein deposits.

Frontotemporal dementia (FTD)

Dementia affecting frontal and temporal lobes.

Parkinson disease dementia (PDD)

Dementia occurring in Parkinson's disease patients.

Vascular dementia (VD)

Dementia caused by reduced blood flow to the brain.

Mixed dementia

Combination of Alzheimer's and vascular dementia.

Cognitive impairment

Gradual decline from baseline cognitive function.

Anterograde amnesia

Inability to form new memories post-event.

Declarative episodic memory

Memory of specific events and experiences.

Neuritic plaques

Extracellular aggregates of amyloid beta protein.

Neurofibrillary tangles

Intracellular aggregates of hyperphosphorylated tau protein.

Hypotonia

Decreased muscle tone and resistance to movement.

Hypertonia

Increased muscle tone and resistance to movement.

Spasticity

Increased resistance with sudden tone reduction.

Dystonia

Sustained involuntary muscle contractions.

Akinesia

Lack of movement due to low dopamine.

Chorea

Irregular, non-repetitive movements due to excess dopamine.

Athetosis

Slow, irregular movements affecting hands and fingers.

Ballism

Wild flinging movements of limbs.

Resting tremor

Tremor at rest, disappears with movement.

Postural tremor

Tremor during maintenance of a position.

Intention tremor

Tremor that worsens as movement approaches target.

Tardive dyskinesia

Medication-induced involuntary movements, often irreversible.

Huntington Disease

Genetic disorder causing chorea and cognitive decline.

Cerebral atrophy

Shrinkage of brain tissue due to neurodegeneration.

Executive function impairment

Reduced ability for abstract reasoning and multitasking.

Behavioral symptoms

Changes in behavior and mood in dementia.

Basal Ganglia

Brain region involved in movement regulation.

GABA

Inhibitory neurotransmitter decreased in Huntington's.

Dopamine

Neurotransmitter elevated in Huntington's and Parkinson's.

Parkinson Disease

Neurodegenerative disorder causing motor dysfunction.

Bradykinesia

Slowness of movement characteristic of Parkinson's.

Resting Tremor

Tremor occurring when muscles are relaxed.

Upper Motor Neuron (UMN) Syndrome

Paresis due to pyramidal tract injury.

Lower Motor Neuron (LMN) Syndrome

Weakness due to peripheral nerve damage.

Amyotrophic Lateral Sclerosis (ALS)

Progressive disease affecting motor neurons.

Focal Muscle Weakness

Initial symptom of ALS affecting limbs.

Seizure

Temporary disturbance in brain's electrical activity.

Epilepsy

Enduring predisposition to generate seizures.

Febrile Seizures

Convulsions in children due to fever.

Tonic-Clonic Seizure

Generalized seizure with tonic and clonic phases.

Absence Seizure

Brief unresponsiveness without convulsions.

Myoclonic Seizure

Sudden, brief muscle contractions.

Atonic Seizure

Sudden loss of muscle tone.

Simple Partial Seizure

Localized seizure without loss of consciousness.

Complex Partial Seizure

Localized seizure with altered awareness.

Seizure Triggers

Factors that provoke seizure activity.

tPA

Tissue Plasminogen Activator for ischemic strokes.

Dysarthria

Speech difficulty due to motor control issues.

Dysphagia

Difficulty swallowing often seen in ALS.

Post-Ictal State

Recovery phase after a seizure.

Cognitive Impairment

Difficulty with thinking and understanding.