Major Changes that Occurs on the Neurological System

Define delirium and dementia specified similarities and differences and describe causes for each one.

Neurological Changes Associated with Aging

As individuals age, significant changes occur in both the central nervous system (CNS) and peripheral nervous system (PNS). These changes can affect cognitive function, motor skills, reflexes, and sensory perception.

Central Nervous System (CNS) Changes

1. Brain Atrophy – The brain decreases in volume and weight due to neuron loss, particularly in the frontal and temporal lobes.
2. Decreased Neurotransmitters – Levels of neurotransmitters such as dopamine, serotonin, and acetylcholine decline, leading to slower cognitive processing and mood changes.
3. Reduced Cerebral Blood Flow – Blood flow to the brain decreases, potentially impairing cognitive function and increasing the risk of stroke.
4. Slower Synaptic Transmission – Reduced synaptic plasticity leads to slower reaction times and impaired memory formation.
5. Accumulation of Neurofibrillary Tangles and Amyloid Plaques – These structural changes, common in conditions like Alzheimer’s disease, contribute to cognitive decline.

Peripheral Nervous System (PNS) Changes

1. Reduced Nerve Conduction Velocity – Slower signal transmission results in delayed reflexes and motor responses.
2. Loss of Sensory Receptors – Decreased tactile sensitivity and proprioception (awareness of body position) increase the risk of falls.
3. Decline in Autonomic Nervous System Regulation – Impaired autonomic function can lead to issues such as orthostatic hypotension and decreased ability to regulate body temperature.
4. Peripheral Neuropathy – Common in aging, especially in individuals with diabetes, causing numbness, tingling, or weakness in extremities.

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Delirium vs. Dementia

Definitions

• Delirium – A sudden, acute disturbance in attention, awareness, and cognition, usually reversible and caused by an underlying medical condition or external factors.
• Dementia – A chronic, progressive decline in cognitive function, including memory, reasoning, and executive functioning, often irreversible.

Similarities

• Both conditions affect cognitive function and can cause confusion, disorientation, and impaired judgment.
• Both are more common in elderly individuals.
• Underlying medical conditions can contribute to both (e.g., infections, metabolic imbalances).

Differences

Feature	Delirium	Dementia
Onset	Sudden (hours to days)	Gradual (months to years)
Course	Fluctuating (symptoms worsen and improve throughout the day)	Progressive (worsens over time)
Reversibility	Often reversible if underlying cause is treated	Irreversible in most cases
Attention	Impaired (inability to focus)	Often preserved until late stages
Memory	Short-term memory loss	Progressive memory decline (short-term first, then long-term)
Hallucinations	Common, especially visual	Less common, but can occur in late stages
Causes	Acute illness, infections, medication side effects, dehydration, electrolyte imbalances, surgery, ICU hospitalization	Neurodegenerative diseases (e.g., Alzheimer’s, vascular dementia, Lewy body dementia)

Causes

• Delirium

  • Infections (e.g., UTIs, pneumonia)
  • Metabolic imbalances (e.g., hypoglycemia, dehydration)
  • Medications (e.g., sedatives, opioids, anticholinergics)
  • Post-surgical complications
  • Substance withdrawal or intoxication

• Dementia

  • Alzheimer’s disease – Most common cause, linked to beta-amyloid plaques and neurofibrillary tangles.
  • Vascular dementia – Caused by stroke or chronic reduced blood flow to the brain.
  • Lewy body dementia – Characterized by abnormal protein deposits in the brain.
  • Frontotemporal dementia – Affects personality and behavior more than memory in early stages.

Understanding these neurological changes and disorders is crucial for healthcare providers, particularly in geriatric and psychiatric care, to ensure proper diagnosis, treatment, and support for aging individuals.