Hyposensitivity: Causes, Symptoms, and Medical Links to Sensory Under-Responsivity

Hyposensitivity (sensory under-responsivity) = diminished detection or reaction to sensory input (touch, temperature, pain, proprioception, vestibular, auditory, visual, olfactory, gustatory). It is a symptom, not a diagnosis.

Common Etiologies

System	Conditions
Peripheral nervous system	Diabetic neuropathy, B12/folate deficiency, chemotherapy (CIPN), toxic (alcohol, heavy metals), hereditary (CMT), compression (carpal tunnel, radiculopathy)
Central nervous system	Stroke (thalamus, parietal), MS (dorsal columns), spinal cord injury, TBI, syringomyelia, posterior cortical atrophy
Medication effects	Opioids, gabapentinoids, TCAs, antipsychotics, anesthetics, anticonvulsants
Developmental	Autism (sensory seeking/under-responsive subtype), SPD, dyspraxia
Aging	Presbyesthesia — ↓ mechanoreceptors, slowed conduction, cortical thinning

Clinical Manifestations

• Touch: Misses light touch, unaware of soiled clothing, high pain threshold (burns, ulcers unnoticed).
• Proprioception: Clumsiness, falls, misjudges force (crushing cups, slamming doors).
• Vestibular: Seeks intense movement (spinning, crashing), poor motion sickness.
• Interoception: Misses hunger, thirst, bladder fullness, heartbeat — Alexithymia link.
• Temperature: Unaware of fever, frostbite risk, scalding bath water.

Evaluation

1. Detailed sensory history (SI profile questionnaires).
2. Neurologic exam: light touch, pinprick, vibration, proprioception, graphesthesia, stereognosis.
3. NCS/EMG, MRI, labs (HbA1c, B12, methylmalonic acid, TSH, SPEP).
4. OT sensory integration assessment (SIPT, SP-2).

Management

• Treat underlying cause: Glycemic control, B12 replacement, medication review, disease-modifying therapy.
• Sensory enrichment (OT): Weighted input, vibration, resistive play, tactile bins — builds cortical maps.
• Compensatory strategies: Visual checks (skin inspection q12h), timers for voiding/eating, thermostatic mixer valves, high-contrast markings.
• Safety engineering: Anti-scald devices, fall alarms, GPS trackers if wandering.

Hyposensitivity is a safety risk — not just "clumsiness." Systematic assessment prevents burns, fractures, pressure injuries, and delayed illness recognition.