CFS Cognitive and Neurological Aspects of CFS 2 — Questions and Answers
Question 1: Autonomic nervous system dysfunction in CFS most commonly presents as:
- Increased parasympathetic tone causing bradycardia
- Orthostatic intolerance with symptoms worsening upon standing (Correct answer)
- Hypertension and hyperventilation at rest
- Hypothermia and reduced sweating
Correct answer: Orthostatic intolerance with symptoms worsening upon standing
Orthostatic intolerance—where symptoms worsen when standing upright—is the most common manifestation of autonomic dysfunction in CFS, often accompanied by heart rate changes.
Question 2: Postural Orthostatic Tachycardia Syndrome (POTS), which frequently co-occurs with CFS, is characterized by:
- A significant decrease in heart rate when moving from lying to standing
- Blood pressure dropping more than 20 mmHg within 3 minutes of standing
- A heart rate increase of ≥30 bpm within 10 minutes of standing (Correct answer)
- Irregular heartbeat rhythm triggered by orthostatic stress
Correct answer: A heart rate increase of ≥30 bpm within 10 minutes of standing
POTS is defined by a heart rate increase of ≥30 bpm within 10 minutes of standing (or ≥40 bpm in adolescents) without a significant drop in blood pressure.
Question 3: Central sensitization, observed in many CFS patients, primarily affects:
- Peripheral pain receptors in skin and muscles
- Immune system response to pathogens
- Pain processing pathways in the central nervous system (Correct answer)
- Hormonal regulation of pain perception
Correct answer: Pain processing pathways in the central nervous system
Central sensitization refers to amplification of pain signals within the central nervous system, causing heightened pain perception in CFS patients even without tissue damage.
Question 4: Neuroinflammation research in CFS has primarily implicated which type of brain cells in the inflammatory process?
- Astrocytes
- Oligodendrocytes
- Neurons
- Microglia (Correct answer)
Correct answer: Microglia
Microglia, the brain's resident immune cells, have been found to be activated in CFS neuroinflammation studies, suggesting an ongoing neuroinflammatory process.
Question 5: The hypothalamic-pituitary-adrenal (HPA) axis abnormality most commonly found in CFS is:
- Elevated basal cortisol levels
- Blunted or reduced cortisol response to stress (Correct answer)
- Complete cortisol deficiency
- Excessive cortisol response to minor stressors
Correct answer: Blunted or reduced cortisol response to stress
Many CFS patients show a blunted or reduced cortisol response to stress, suggesting HPA axis hypofunction rather than the elevated cortisol typically seen in depression.
Question 6: Sensory hypersensitivity in CFS most commonly includes sensitivity to:
- Taste and proprioception only
- Light (photophobia) and sound (phonophobia) (Correct answer)
- Temperature changes only
- Vestibular stimulation only
Correct answer: Light (photophobia) and sound (phonophobia)
Photophobia (sensitivity to light) and phonophobia (sensitivity to sound) are among the most commonly reported sensory hypersensitivities in CFS patients.
Question 7: Small fiber neuropathy (SFN), found in a subset of CFS patients, affects which type of nerve fibers?
- Large myelinated motor nerve fibers
- Large myelinated sensory nerve fibers
- Small unmyelinated or thinly myelinated nerve fibers (Correct answer)
- Autonomic nerve fibers exclusively
Correct answer: Small unmyelinated or thinly myelinated nerve fibers
Small fiber neuropathy affects the smallest nerve fibers (unmyelinated C-fibers and thinly myelinated Aδ-fibers) responsible for pain, temperature, and autonomic signaling.
CFS Cognitive and Neurological Aspects of CFS 2
Autonomic nervous system dysfunction in CFS most commonly presents as: