Certain industries require their employees to submit their polygraph examination results. In such cases, it is very important to find a well-certified polygraph examiner to conduct your polygraph examination.
If you are trying to get a lie detector test in Oklahoma keep reading to understand everything you need to know about polygraph examination.
Polygraph:
A polygraph is a lie detector machine that records and measures the physical responses from our body such as,
- Blood volume
- Heart rate
- Sweat levels (Galvanic skin responses)
- Breathing patterns
How does Polygraph testing work?
The person who is taking the test is connected to the polygraph device with sensors attached.
A series of questions will be asked by the examiner. Based on the answers provided the body’s physical reaction will help the examiner determine whether the person is lying or not.
in the body happen due to the sympathetic nervous system, which either marks it as nervous or stressed which generally happens when a person is lying.
We will now discuss more about the tests.
- Skin conductivity
- Heart rate
- Blood volume
- sympathetic nervous system
Electrodermal activity (EDA)
Electrodermal activity (EDA), formerly known as galvanic skin response (GSR), is a measure of the skin’s electrical characteristics that changes with sweat gland activity and is controlled by the sympathetic nervous system. It offers insight into psychological and physiological arousal.
EDA was discovered in 1849 by Dubois-Reymond. Key milestones include:
- In 1878, Hermann and Luchsinger connected EDA to sweat glands.
- In 1879, Vigouroux linked EDA to psychological activity.
- In the early 1900s: C.G. Jung applied EDA to psychoanalysis.
- Wilhelm Reich used EDA to investigate bioelectrical charges between 1935 and 1936.
- EDA assesses variations in skin conductance caused by sweat gland activity, which varies with emotional and sympathetic reactions. These measures can detect arousal, but not specific emotions.
Examples and Uses
EDA reactions can be elicited by pain, fear, or shame stimuli. It is utilized in polygraph testing, biofeedback treatment, neurological evaluations, and stress studies.
Challenges
Both environmental elements like temperature and humidity and interior factors such as drugs and hydration can influence EDA measures. Different body regions can provide different outcomes due to differences in sweat gland concentrations and brain region impacts.
Current Applications
EDA remains a common tool for researching psychophysiological phenomena, and it is increasingly employed in therapeutic settings to measure emotional and cognitive states.
Heart Rate
Heart rate is the frequency of the heartbeat, measured in beats per minute (bpm). It fluctuates with the body’s physical requirements, such as oxygen intake and carbon dioxide excretion. Heart rate is influenced by heredity, physical fitness, stress, food, medicines, hormones, the environment, and sickness.
Normal Heart Rate
The resting adult human heart rate is 60-100 beats per minute.
Ultra-trained athletes have a heart rate of 37-38 beats per minute.
Tachycardia (high heart rate): more than 100 bpm at rest.
Bradycardia is defined as a heart rate of less than 60 beats per minute at rest.
Sleep: 40-50 bpm.
Physiology
The autonomic nervous system influences the sinoatrial (SA) node, which regulates the heart rhythm.
Sympathetic input (accelerans nerve) releases norepinephrine and raises the heart rate.
Parasympathetic input (vagus nerve): Releases acetylcholine, and lowers heart rate.
Regulation
Sympathetic stimulation boosts heart rate by hastening depolarization and contraction.
Parasympathetic stimulation lowers heart rate by delaying depolarization and lengthening repolarization.
Nervous System Influence
- Cardiovascular centers are located in the medulla oblongata and contain cardioaccelerator and cardioinhibitory centers.
- Sympathetic fibers densely innervate the heart, producing norepinephrine to raise the heart rate.
- Parasympathetic fibers release acetylcholine, typically via the vagus nerve, to slow the heart rate.
Input for Cardiovascular Centers:
- Proprioreceptors monitor physical activity and regulate heart rate accordingly.
- Baroreceptors are stretch receptors found in numerous blood arteries that regulate blood pressure.
- Chemoreceptors: Detect metabolic byproducts and oxygen levels and alter blood flow accordingly.
- Limbic system: Emotions influence heart rate, with stress raising and meditation reducing it.
Blood volume (volemia)
Blood volume, often known as volemia, refers to the entire amount of blood (including blood cells and plasma) in an individual’s circulatory system.
Human Blood Volume
Typical Adult: Around 5 liters.
Percentage of Body Weight: Around 7-8% for both males and females.
Regulation: controlled by the kidneys.
Calculation
Blood volume (BV) may be determined using hematocrit (HC), the proportion of blood that is red blood cells, and plasma volume (PV).
= 1 − BV= 1−HC PV
Clinical Relevance
Blood volume measurement can help diagnose and manage disorders like:
- Congestive Heart Failure
- Chronic hypertension.
- Kidney failure.
- Critical care.
Measurement Techniques
Dual Isotope or Tracer Technique
To label blood, two tracers are used: 51Cr-RBC for red blood cells and I-HAS for plasma. Involves injecting, withdrawing, and reinfusing the patient’s blood.
Time: This can take up to six hours.
Classic approach, available since the 1950s. Semi-automated system (BVA-100).
Product: BVA-100 by Daxor Corporation.
Description: This FDA-cleared diagnostic instrument measures Total Blood Volume (TBV), Plasma Volume (PV), and Red Cell Volume (RCV) with 98% accuracy in 60 minutes.
Principle: Injects I-131 albumin and centrifuges microhematocrit.
Process: Five blood samples are collected at 6-minute intervals.
Carbon Monoxide (CO) Rebreathing Method
Sympathetic Nervous System:
The autonomic nervous system is divided into three parts: the sympathetic nervous system (SNS), the parasympathetic nervous system, and the enteric nervous system. The enteric nervous system is sometimes considered a component of the autonomic nervous system and occasionally a separate entity.
Structure
The SNS uses two types of neurons for signal transmission:
pre-ganglionic and post-ganglionic neurons.
Preganglionic neurons originate in the thoracolumbar division of the spinal cord (T1 to L2~L3) and synapse in ganglia with postganglionic neurons, extending to target tissues.
Preganglionic neurons release acetylcholine, which activates nicotinic acetylcholine receptors in postganglionic neurons.
Postganglionic neurons release norepinephrine, which stimulates adrenergic receptors in peripheral target organs.
Organization
The SNS runs from the thoracic to the lumbar vertebrae and links to the thoracic, abdominal, and pelvic plexuses. Sympathetic nerves begin in the intermediolateral nucleus of the lateral grey column, which runs from the first thoracic vertebra to the second or third lumbar vertebra. These nerves leave the spinal cord via the anterior root and enter the anterior rami of spinal nerves. They then split via white rami connections to either paravertebral or prevertebral ganglia.
