Sensation: Types, Causes, and How It Affects Perception

Sensation is the process by which sensory receptors detect stimuli from the external or internal environment and transmit this information to the brain. It is the first step in perception, allowing the brain to interpret and respond to sensory experiences. Sensation occurs through specialized sensory organs, including the eyes, ears, skin, tongue, and nose.

Types of Sensation

1. General Sensation – Detected by the skin and internal organs:
• Tactile Sensation – Touch, pressure, vibration.
• Pain Sensation – Detects harmful stimuli.
• Temperature Sensation – Hot and cold perception.
• Proprioception – Awareness of body position and movement.
2. Special Sensation – Processed by specific sensory organs:
• Visual Sensation – Processed by the eyes (light, color, shapes).
• Auditory Sensation – Processed by the ears (sound, pitch, volume).
• Olfactory Sensation – Processed by the nose (smell).
• Gustatory Sensation – Processed by the tongue (taste: sweet, sour, bitter, salty, umami).
• Vestibular Sensation – Maintains balance and spatial orientation (inner ear).

Theories of Sensation

1. Specific Nerve Energy Theory – Each sensory nerve transmits only one kind of sensation (Johannes Müller).
2. Gate Control Theory of Pain – Pain perception is controlled by a “gate” in the spinal cord that can be opened or closed.
3. Trichromatic Theory of Vision – The eye perceives color through three types of cone cells (red, green, and blue).
4. Opponent-Process Theory – Colors are perceived in opposing pairs (red-green, blue-yellow, black-white).

Causes of Sensory Disorders

• Neurological Factors – Stroke, multiple sclerosis, nerve damage.
• Metabolic & Deficiency Disorders – Vitamin B12 deficiency, diabetes (neuropathy).
• Infectious Diseases – Meningitis, syphilis, leprosy.
• Aging-Related Degeneration – Loss of hearing (presbycusis), vision (cataracts).
• Trauma & Injury – Spinal cord injury, burns, head trauma.

Clinical Features, Signs & Symptoms of Sensory Disorders

• Numbness, tingling, or loss of touch sensation.
• Pain or hypersensitivity to stimuli.
• Loss of vision, hearing, smell, or taste.
• Dizziness, balance problems, or disorientation.
• Inability to detect temperature or proprioception disturbances.

Investigations

1. Neurological Examination – Tests for sensory deficits (pinprick, vibration, proprioception).
2. Electrophysiological Tests – Nerve conduction studies, EEG, EMG.
3. Neuroimaging – MRI, CT scan to detect brain or nerve damage.
4. Ophthalmic & Audiometric Tests – Eye and ear function tests.
5. Blood Tests – To check for vitamin deficiencies or metabolic disorders.

Treatment & Management

• Medical Management – Treating underlying conditions (diabetes, vitamin deficiencies).
• Physical Therapy – Exercises to improve proprioception and balance.
• Sensory Integration Therapy – Used in sensory processing disorders (e.g., autism).
• Pain Management – Medications, acupuncture, nerve stimulation techniques.
• Assistive Devices – Hearing aids, glasses, prosthetic limbs for sensory loss.

Homeopathic Remedies

1. Agaricus Muscarius – Numbness, tingling, burning sensations in the body.
2. Hypericum Perforatum – Nerve pain, hypersensitivity after injury.
3. Phosphorus – Vision disturbances, light sensitivity, auditory hypersensitivity.
4. Silicea – Weakness of senses, difficulty in perceiving stimuli.
5. Belladonna – Acute sensory hypersensitivity, sudden pain, bright light intolerance

PSYCHOLOGY INCLUDES:-

1. Mind
2. Behavior
3. Sensation
4. Perception
5. Illusion
6. Hallucination
7. Delusion
8. Memory
9. Thinking
10. Motivation
11. Emotion
12. Imagination and Image
13. Intelligence
14. Aptitude
15. Attention
16. Personality
17. Frustration
18. Conflict
19. Anxiety
20. Psychosomatic manifestation
21. Dreams
22. Developmental Psychology