Dr. Ernesto Korenman's presentation about Electro dermal activity biofeedback

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Stress Management and Biofeedback
Workshop
Electro-
Electro-dermal Activity (EDA) Physiology
Sweat Gland Physiology
By: Dr. Ernesto Sh. Korenman, July/2008
July/2008
Dr. Ernesto Sh. Korenman, 2008
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Sweat Glands Skin
• Glands secrete 99 % water with
dissolved salts, traces of ammonia,
and other metabolic by-products.
by-
• Can collectively produce up to 7-8
liters a day. Outermost Layer: Epidermis
• Humans contain about 2.5 million
sweat glands in our body. Middle Layer: Dermis
Deepest Layer: Hypodermis
Blood Vessels
Sweat Gland
Neural innervations
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Control of Eccrine Sweat Glands Sweat Glands: types
• Activation is controlled directly by the • One type of sweat gland occurs in the palms,
Sympathetic Division of the Autonomic Nervous soles, forehead, and armpits
System › Control body temperature
› Function in cold sweats = responses made
when you are frightened, nervous or
• Paradoxically receive primarily sympathetic embarrassed
cholinergic fibers (Acetylcholine releasing)
• Other sweat glands occur on other body
surfaces
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Skin Conductance and sweat
• Skin conductance
begins to change
before moisture
Emotional Sweating level
• As duct fills with
sweat, skin
conductance
increases
Sweat gland
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Sweat Gland response to stressing sound Sweat-
Sweat-emotion link: the Limbic System
Thalamus Cortex
Hyppocampus
Threatening Sound
Amygdala
Thalamus
Auditory Cortex
Hypothalamus
Limbic System Cerebellum
Medulla
• Limbic System activates the sweating pathway controlled by
Hypothalamus the Hypothalamus.
• Affected by, and responds to, emotional stimulus, such as
Sweat Gland response emotionally charged questions
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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EDA electrodes
Electrodermal Activity (EDA)
Recording
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Sweat gland and skin conductance What is skin conductance?
Current (I)
• Resistance R=V/ I (Ohms)
R=
Battery
• Conductance C = 1/ R
Voltage (V) (mho or Siemens)
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Skin conductance/resistance units Sweat and EDA
• Phasic skin conduction response (greater conductance) occurs due to filling
of the sweat ducts in the epidermis and the constant expulsion of fluids from
the sweat pores
• Recovery to tonic levels of skin conductance is attributed to deposition of
moisture on the skin or re-absorption of fluids by the sweat glands
re-
• Amount of sweat delivered to the ducts and number of sweat glands that
are activated influence the amplitude of the conductance response
• Glands on the palmar and plantar surface have been recognized as
responding to emotional stimuli, with the remainder responding to thermal
changes
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Quantification of EDA response (EDR) Skin conductance response
- Latency
- Amplitude
-Recovery
• Skin becomes a better
conductor of electricity
when external stimuli
are presented
Stimulus
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Types of real SCL graph SCL graph
Relaxing
Cumulated
stimuli
Steady Labile Recovery
after stimuli
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Respiration artifact detection Specific (Sp) vs. non-specific response
non-
Specific Non Specific
Non Specific Specific
Specific
Non
Specific
TW=Time Window
Inhale Inhale
Stimulus Stimulus
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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Habituation of SCR to tone SCR to fearful music
=Tone
3 Run1
1.5
0
Skin Conductance
Response (µS)
(µ
3 Run2
1.5
0
3 Run3
1.5
0
10 50 90 130
Time (sec)
Dr. Ernesto Sh. Korenman, 2008 Dr. Ernesto Sh. Korenman, 2008
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The End
Dr. Ernesto Sh. Korenman, 2008
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