Carbon Monoxide Headquarters

Glossary:


ACGIH - American Conference of Governmental Industrial Hygienists.

Acute - A condition involving relatively brief periods of time. For CO exposure, acute is defined as an exposure of up to 10-15 hrs or less, involving one major exposure.

ADD - Attention Deficit Disorder

ADHD - Attention Deficit Hyperactivity Disorder

Affect - The outward, often facial, manifestations of subjective feelings or emotions.

Agnosia - Inability to perceive objects through otherwise normally functioning sensory channels.

Akinesis - Inability to initiate changes in activity and to perform ordinary volitional movements rapidly and easily. It is the most disabling feature of Parkinson's disease.

Alzheimer's Disease - About 55% of dementia are due to early- or late-onset Alzheimer's disease; involves the abnormal production of the protein amyloid.

Amnesia - Loss of memory function; short-term, longterm, or both; can be transient or lasting.

Amygdala (amygdaloid nucleus) - Coordinates autonomic and endocrine responses in conjunction with emotional states; part of the limbic system.

Anemic Hypoxia - A condition in which the arterial PO2 is normal, but the amount of hemoglobin available to carry O2 is reduced and/or the ability to release O2 to the tissues is impaired.

Angina - Pain, usually in the chest, but sometimes in the neck, arm, jaw, etc. resulting from inadequate blood flow to the heart muscle (coronary ischemia).

Anhedonia - An inability to experience pleasure.

Aphasias - Disturbances of language ability. An inability to understand or produce language, not related to sensory or motor deficit.

Aphonia - Inability to speak or produce normal speech sounds.

Apraxia - Inability to perform complex acts requiring sequences of muscle contractions or a planned strategy. Loss of a motor skill not explained by simple weakness or previously existing incoordination.

Asphyxia - Suffocation, decrease in the oxygen content, and increase in carbon dioxide content of the blood. Term includes all causes of tissue hypoxia, including exposure to asphyxiant gases (low O2), narcotic gases such as CO and HCN.

Asterixis - Quick arrhythmic movements that occur due to brief interruptions in background tonic muscular contractions. A neurological sign characterized by flapping of the hands, associated with toxic or metabolic encephalopathy.

Ataxia - Abnormalities in the execution of voluntary movements. Muscle incoordination, especially affecting gait.

Athetosis - Inability to sustain muscles of the fingers, toes, tongue or any other group of muscles in one position; maintained posture is interrupted by continuous slow, purposeless movements.

Autistic - Refers to autism. Marked disturbances in relating to, and apparent unawareness of others and one's environment.


Balint's syndrome - Condition of psychic paralysis or visual fixation, optic ataxia, and disturbance of visual attention. Due to bilateral damage to the parietal-occipital regions, causing problems with visually guided motor movments.

Basal Ganglia - Made up of the caudate nucleus and putamen (known together as the corpus striatum) and the globus pallidus. Roles in regulating movement and cognition. Damage to it causes seizure disorders, multiple-sclerosis-type disorders, decrement in intellectual capacity, judgment, ability to concentrate, memory, speech capability.

b.i.d. - Twice daily

Brainstem Auditory Evoked Potentials - The cortical effects of auditory stimuli are recorded and analyzed.

Broca's area - Region of the frontal lobe on left, that makes spoken language possible.


Carboxyhemoglobin (COHb) - Combination of CO with hemoglobin in the blood, which prevents O2 attachment to hemoglobin and thus transport of O2 to the tissues.

Catatonic - Any of several striking motor abnormaliti, generally described as related to a psychosis, including extreme excitement, stupor, negativism, rigidity, or posturing.

Caudate Nucleus - Part of basal ganglia; damage causes forms of aphasia.

Cephalea (cephalgia) - Headache, pain in the head.

Cerebral Cortex - Expansive mass of brain tissue covering the older parts of the brain including cerebral hemispheres and formed of sulci, consisting of 4 parts (frontal, parietal, occipital, temporal); 6th division of the CNS; involved in vision, hearing, learning, memory, association, etc.

Cerebral Depression - Condition in which the electrical activity (EEG) of the cerebral cortex shows mainly slow wave activity, typical of semiconscious or unconscious state.

Cerebellum - Occupies most of the posterior cranial fossa; damage produces ataxia, slurring of speech.

Cerebral Hemispheres - Made up of the basal ganglia, hippocampus and amygdala; overlaid by cerebral cortex; affects emotion, learning

Cheyne Stokes - Characterized by rhythmic waxing and waning of the depth of ventilation, with a regular pattern of apnea, hyperventilation, etc.

Chorea - Widespread arrhythmic movements of a forcible, rapid, jerky, restless type; movements are irregular and variable, but continuous. They may be simple or quite elaborate, and affect any part of body. Can be caused by damage to the caudate nucleus.

Choreiform - Writhing

Chronic - A condition involving relatively long periods of time. For CO exposure, chronic is defined as an exposure of 10-15 hrs or more, and may involve one or cycles of exposure.

Cingulate Gyrus - This area, together with the parahippocampal gyrus and the olfactory bulbs, comprises the limbic cortex, which modifies behavior and emotions.

CNS Depressant - A substance that causes sedation of the central nervous system.

Cog Wheel Regidity - A condition in which a limb moves about its axis with uneven resistance.

Coma - A state of altered consciousness, sharing some characteristics with sleep, but not usually arousable from, unlike sleep.

Concentration - The amount of one substance mixed with another substance, usually stated as mass per volume (eg. mg/L or mg/m3), or volume per volume (ppm or percent).

Confabulation - Creation of inaccurate memories or fabrications, unconsciously, to substitute for unrecalled events.

Congenital - Present at birth, but not necessarily implying genetic or familial transmission.

Constructional Apraxia - Loss of the ability to produce or copy drawings, shapes, or designs.

Continence - The ability to control voluntarily one's urination or defecation.

CT (or CAT) - Computed tomography, or Computed axial tomography. Multiple radiographs of body structure assisted by computer analysis.


Dementia - An organically caused mental disorder characterized by loss of previously held mental abilities, including intellect, memory, and judgment.

Dentate Nuclei - One of three deep nuclei within the cerebellum.

Depression - A sad, despairing, or discouraged mood; such a mood or feeling sufficient to be a symptom or a mental disorder; a syndrome characterized by depressed mood.

Diencephalon - 5th division of the CNS.

Diplopia - Double vision.

Dose - The amount of substance to which an individual is exposed.

Dysarthria - Difficulty speech production; related to anatomical or coordination deficit.

Dyscalculia - Inability to carry out mathematical calculations.

Dysfluency - A disturbance of language fluency.

Dyskinesia - A movement disorder involving involuntary muscle contractions; may be mild or severe (eg. hemiballismus).

Dyslexia - Disorders with reading; congenital or acquired. Difficulty understanding or manipulating words that is not related to education or intelligence.

Dysphagia - Difficulty swallowing.

Dyspnea - Difficulty in breathing

Dyspraxia - A disturbance in the programming, control, and execution of volitional movements. Usually resulting from any condition affecting the cerebral hemispheres.

Dyssomnia - A disorder of sleep, whether organic or functional.

Dysthymia - Mental depression, any intellectual anomaly

Dystonia - Abnormally increased muscular tone that causes fixed abnormal postures; sometimes shifting postures result from irregular, forceful twisting movements that affect the trunk and extremities. A persistent attitude or posture in one or other of the extremes of athetoid movement, produced by co-contraction of agonist and antagonist muscles in one region of the body.


ECG - Electrocardiogram. Record of heart electrical activity, usually obtained from electrodes located on the surface of the body.

Echolalia - Limited ability to speak unless spoken to; response usually a direct echo of examiner.

Edema - Accumulation of an excessive amount of fluid in cells, tissues or body cavities.

EEG - Electroencephalogram. Record of brain electrical activity, usually obtained from electrodes located on the surface of the skull.

Emesis - The act of vomiting.

Encephalopathy - Damage caused to the brain by whatever mechanism.

EPA - Environmental Protection Agency (U.S.A.)

Epilepsy - An intermittent derangement of the nervous system due presumably to a sudden, excessive, disorderly discharge of cerebral neurons.

Erythema - Reddening of the skin in response to heat.

Etiology - Cause.

Extra-pyramidal Signs - Many different phenomena which are due to primary deficits (negative symptom), or new disinhibited actions that have appeared due to lesions associated with the basal ganglia.


Fornix - A pathway of nerve fibers that transmits information from the hippocampus and other limbic areas to the mamillary body.

Frontal Lobe - Area of cerebrum; speech production, the elaboration of thought and emotion, and skilled movements are controlled here.


Gilles de la Tourette's syndrome - A syndrome of facial and vocal tics with onset in childhood, progressing to generalized jerking movements in any part of the body, with echolalia and coprolalia.

Globus Pallidus - Part of the basal ganglia. Damage can result in flexion dystonia, impaired postural reflexes.

Gran Mal - A form of seizure including both loss of consciousness and generalized movements.

Gray Matter - Made up of groups of neuron cell bodies.


Haber's Rule - Principle that toxicityin inhalation toxicology depends on the dose available and that the product of concentration and exposure time is a constant.

Habit Spasms - Seemingly voluntary movements but which individuals feel compelled to do to relieve tension (eg. sniffing, clearing of throat, pulling on collar).

HBO - Hyperbaric Oxygen (therapy).

Hemiballismus - Hyperkinetic movement disorder characterized by violent flinging motions in the arm contralateral to a lesion in or near the subthalamic nucleus. May be due to damage in basal ganglia.

Hemiplegia - Damage to the motor areas on one side of the brain can lead to paralysis of the opposite side of the body. Paraplegia affects both sides.

Hippocampus - Part of the limbic system; involved in learning and memory storage, the recognition of novelty, and the recollection of spatial relationships; damage produces effects on short- to long-term memory, limbic system.

Histotoxic Hypoxia - A condition in which the amount of O2 delivered to the tissues is adequate, but due to the action of a toxic agent such as HCN, the tissue cells cannot make use of the O2 supplied to them.

Hyperacusis - Overarousal; hypersensitivity to sensory stimulation, especially sounds.

Hypercapnia - Increased blood CO2 concentration.

Hyperglycemia - Blood glucose concentration elevated above normal values (90-108 mg/dL).

Hyperventilation - Increased rate and depth of breathing, ie. increased respiratory minute volume (RMV), in response to increased CO2 hypoxic hypoxia, HCN, exercise, heat, or pulmonary irritant receptors.

Hypervigilance - A condition of emotional and physiological preparedness, to an unnecessary extent, in anticipation of an anxiety-producing stimulus.

Hypoglycemia - Blood glucose concentration depressed below normal values (90-108 mg/dL).

Hypokinesis - Abnormally decreased mobility; abnormally decreased motor function or activity.

Hypothalamus - Controls pituitary; regulates temperature, heart rate, blood pressure, food and water intake (autonomic functions, multi-glandular control); constitutes less than 1% of brain.

Hypoxia - A reduction in the amount of oxygen available for tissue respiration, due to Anemic Hypoxia, Histotoxic Hypoxia, Hypoxic Hypoxia, Ischemic Hypoxia.

Hypoxic Hypoxia - A condition in which the PO2 of th arterial blood is reduced as a result of a low atmospheric oxygen concentration or impairment of gas exchange in the lung, due to bronchoconstriction or respiratory tract damage or disease.


Immediate Memory - In the mental status examination, the portion of memory that exists a few seconds after an event.

Incapacitation - An inability to perform a task caused by exposure to a toxic substance, etc. It could be due to physical (ie. physiological) incapacitation or behavioral incapacitation.

Incidence - In epidemiology, the number of new cases that occur over a given period of time.

Incontinence - Inability to control urination or defecation.

Intention Tremor - A tremor (ataxic, kinetic) that occurs during willed movement; usually during the most demanding phases of movement.

Intoxication - A state in which a subject is adversely affected by a toxic substance.

Ischemic Hypoxia - A condition in which blood flow to a tissue is so low that adequate O2 is not delivered to it despite a normal PO2 and hemoglobin concentration.


Kluver-Bucy Syndrome - Primitive impulse control; symptoms associated with memory defect and other changes; caused by loss of both temporal lobes.


Labile - Rapidly shifting; unstable.

Lacrimation - The production of tears; tearing.

LC50 - Lethal Concentration 50%. The concentration that causes the deaths of 1/2 of the animals exposed to a toxicant for a specified time, expressed as vol./vol. (ppm, %), or mass/volume (mg/L).


Mamillary Body - Acts as a relay station, transmitting information to and from the fornix and thalamus.

MCS - Multiple Chemical Sensitivity. Usually an increased sensitivity to a broad range of chemicals, fumes, hydrocarbons, more complex organic chemicals, etc. which induces various symptoms.

Medulla Oblongata - 2nd division of the C.N.S.

Melancholia - Severe, anhedonic depression.

Memory - Involves several stages. Immediate events are held in sensory memory (seconds), which is then either transferred to short-term memory (minutes-hours) or is forgotten. ST-memory then goes through transfer consolidation and becomes Long-term memory, which can be retrieved (months-years). It is distributed in many areas of the brain.

Meningitis - Infection of the brain casued by a bacterium or virus.

Micrographia - Characterized by very small, cramped handwriting.

Mid-brain - 4th division of the C.N.S.

Migraine - A familial disorder characterized by periodic, commonly unilateral, pulsatile headaches which begin in childhood, adolescence, or early adult life and recur with diminishing frequency during advancing years.

MRI - Magnetic resonance imaging; formerly known as nuclear magnetic resonance). Study of body structure by computer interpretation of the radio frequency radiation from various atoms induced by powerful magnetic fields.

Multiple Sclerosis - Most common disablbing disorder of the CNS affecting the young.

Munchausen's Syndrome - A factitious disorder or set of symptoms.

Mutism - Unable to speak, inarticulate; inability or refusal to speak.

Myoclonus (Clonus, Polymyoclonus) - Very brief, involuntary, random muscular contractions. Myoclus can occur spontaneously at rest, in response to sensory stimuli, or with voluntary movements. Rhythmic or arrhyhthmic series of brief, shock-like (unidirectional) contractions of a group of muscles.

Myonecrosis - Death of muscle cells.


Narcosis - Literally "sleep induction". This can describe CNS depression causing reduced awareness, intoxication, and reduced escape capability, leading to loss of consciousness and death in extreme cases. CO, HCN, CO2, and low O2 cause narcosis.

Neurasthenia - "weakness". This is an historic term used for persons with unexplained chronic fatigue and lassitude. Accompanying these symptoms were usually nervousness, irritation, anxiety, depression, headache, insomnia, and sexual disorders.

Neuroleptic - Antipsychotic medication; also, a neuroleptic medication.

Neuropsychology - That branch of clinical neuroscience that deals with the objective measurement of cognition, memory, and sensory and motor functions of the body, and where present, rehabilitation of impairment [Neuropsychologists normally hold a Ph.D. degree].

Neurotic - Internal, unconscious conflict; also refers to a neurosis.

NIOSH - National Instititute for Occupational Safety and Health (U.S.A.)

Nystagmus - A specific, rhythmic motion of the eyeballs, sometimes in response to certain neurologic tests. Can result from chronic CO exposure.


Occipital Lobe - Area of cerebrum at back of brain; detects and interprets visual images.

OSHA - Occupational Safety and Health Administration (U.S.A.)


Paraphasia - The misuse of spoken words, or word combinations; a form of aphasia. Literal paraphasia - use of unrelated word; semantic paraphasia - use of similar word with different meaning.

Paraphrasia - Condition characterized by loss of ability to use words correctly and coherently

Paraplegia - Damage to the middle or lower area of the spinal cord can cause paralysis of both legs and possibly part of the trunk; control of the bladder and bowel may also be affected, causing incontinence.

Paresthesias - Abnormal or morbid sensation; burning, prickling, etc.

Parietal Lobe - Area of cerebrum; sensations such as touch, pressure, pain, and temperature are both perceived and interpreted.

Parkinson's Disease - Degenerative condition of the brain (1 in 200 people >60 yrs. age); causes weakness and stiffness in muscles and interferes with speech, walking and performance of daily tasks; often accompanied by hand tremor.

Parkinsonism (Parkinsonian) - Relating to symptoms displayed in Parkinson's disease.

Pathognomonic - A symptom or sign that is found in only one disease or disorder, and in no other.

Pathophysiology - Organic abnormality related to disease.

PEL - Permissible exposure limit.

PET Scan - Positron Emission Tomography. Use of elemental isotopes produced by a cyclotron that decay, releasing positrons (positive electrons) which are then used to visualize metabolic function (usually of brain).

Phalen Sign - Sensing of paresthesias in the territory of the median nerve on wrist flexion.

Pons (+ cerebellum) - 3rd division of the C.N.S.

Propriocepticeptive Sense - Awareness of the position and movement of our limbs, fingers, and toes.

Premorbid - Before the onset of illness.

Prognosis - A prediction of the outcome of an illness or disorder, based on clinical experience with similar cases.

Pseudodementia - A dementia-like syndrome not actually related to organic illness.

Psychomotor - Skills involving a series of coordinated movements.

Psychomotor Agitation - Continuous activity related to emotional distress.

Psychomotor Retardation - General slowing of emotional and physical responses.

Psychosomatic - Refers to the interaction between the mind and body, especially illnesses in which emotional disorder or conflict gives rise to, or significantly affects, physical signs or symptoms.

Psychotic - Serious impairment in reality testing, with inaccurate perceptions and/or thoughts about external reality.

Purkinje Cells - A type of cell found in the cerebellar cortex.

Putamen - Part of basal ganglia.


Quadriplegia (tetraplegia) - Damage to the spinal cord in the lower neck can cause paraylsis of the whole trunk plus arms and legs; all four limbs are affected.

q.i.d. - four times a day


Radiograph - An photographic picture of hard and sof tissue made using x-rays.

REM - Rapid Eye Movement; the sleeping state involves both REM and non-REM sleep.

Remote Memory - In the mental status examination, memory for items or events that occurred in the distant past.

Respiratory Minute Volume (RMV) - Volume of air breathed each minute, usually in liters/minute. RMV = Tidal Volume x Respiratory Rate.

Rest Tremor - Occurs when the limb is in an attitude of repose; diminished by willed movement (Parkinsonian).

Reye (Reye-Johnson) Syndrome - Special type of non-icteric hepatic encephalopathy occurring in children and adolescents; characterized by brain swelling.

Rhabdomyolysis - An acute, sometimes fatal disease characterized by the destruction of skeletal muscle.

Rigidity - Muscle tone is high and there is continuous contraction and resistance to passive movement

Romberg's Sign - Inability to balance on two feet with eyes closed; then referred to as positive (+).


SEM - Scanning Electron Microscopy.

Sign - Any objective evidence or manifestation of an illness or disordered function of the body.

Sleep Apnea - Any of several physiologically based conditions in which one stops breathing while asleep.

S.O.B. - Shortness of Breath. Related to dyspnea.

Somatic - Refers to the body or human biology.

Somnolence - Sleepiness, abnormal drowsiness

SPECT Scan - Single photon emission computed tomography. A technique evolved from PET, using isotopes that are incorporated into biologically active compounds. Technique allows the study of cerebral blood flow, tissue metabolism, neuroreceptors, and metabolism of glucose and amino acids.

STEL - Short-term exposure limit

Stereognosis - The faculty of perceiving and understanding the form and nature of objects by the sense of touch.

Stroke - Interruption or loss of brain function due to blockage or rupture of a blood vessel.

Stuporous - Physically and verbally unresponsive, especially because of an illness, intoxication, injury, or altered state of consciousness.

Subacute - Having the potential to become acute; likely to become acute.

Substantia nigra - An area of the midbrain. Lesions can result in akinesia. Due to tremor at rest of Parkinson's disease

Subthalamic nuclei - An area within the basal ganglia

Sympathomimetic - A substance whose action mimics that of the sympathetic nervous system.

Symptom - An outward manifestation of pathological condition, perceived by the patient, especially a subjective complaint.

Syncope - Faint; loss of consciousness

Syndrome - A group of symptoms and/or signs associated with each other, sometimes suggesting a particular disorder or diagnosis.

Synergism: - A condition where the toxic effects of two or more substances acting together is greater than the sum of the effects of each substance acting alone.


Tachycardia - Increase in heart rate

Tachypnea - Increase in breathing rate.

TEM - Transmission Electron Microscopy.

Temporal Lobe - Area of cerebrum; recognition of specific tones and loudness takes place here; also, this area plays a role in memory storage.

Thalamus - Part of cerebral hemispheres; process information reaching the cerebral cortex from rest of C.N.S.

Tic - Characterized by stereotyped, purposeless, and irregularly repetitive movements. Gilles de la Tourette's syndrome is the most common and severe form of multiple tic disorder.

Tidal Volume (TV) - The volume of air inhaled or exhaled during each respiratory cycle.

t.i.d. - three times a day.

Tinel's Sign - Cutaneous tingling sensation produced by pressing on or tapping the nerve trunk that has been damaged or is regenerating following trauma; tingling upon percussion of a regenerating nerve.

Tinnitus - Sounds in the ears - ringing, buzzing, humming, whistling, roaring, hissing, clicking, chirping, or pulse-like sounds have been reported.

Titibulation - Rhythmic oscillations of the head and trunk.

TLV - Threshold limit value.

Toxicity - The nature and extent of adverse effects of a substance upon a living organism.

Tremor - Rhythmic oscillations of a part of the body around a fixed point; usually involve the distal parts of limbs, the head, tongue or jaw.

Tricyclic - In psychopharmacology, a class of antidepressant medications.

TWA - Time weighted average.


Unconscious - Out of awareness; not under voluntary control; that part of the psyche not available to voluntary control or awareness.


Ventricles - Fluid-filled chambers in the brain. Fluid produced in the lateral ventricles drains via the interventricular foramen into the third ventricle, then flows through the cerebral aqueduct and into the fourth ventricle, located in the front of the cerebellum.

Vertigo - A feeling of dizziness, usually including the sensation that one's environment or oneself is spinning.

Visual Tracking - Following objects with one's eyes.


White Matter - Composed mainly of myelin-covered axons, or nerve fibers, that extend from the neuron cell bodies.

WHO - World Health Organization.


...... last changed 04/26/02



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