What are the 6 clues of HGN?
- CHECK EQUAL TRACKING & PUPIL SIZE. Equal Tracking Yes No. Equal Pupil Size Yes No.
- CLUES: LEFT RIGHT. *Lack of Smooth Pursuit. 2 seconds out; 2 seconds back. *Distinct Nystagmus. @Maximum Deviation. Hold minimum of 4 seconds.
- TOTAL SCORE: (Decision Point: 4; Max: 6)
How many clues do you need for HGN?
How many clues do you need for HGN? There are a total of three clues that can be assessed in this test: lack of smooth pursuit, distinct nystagmus at maximum deviation, and the onset of nystagmus prior to 45 degrees. Each eye is scored independently for three clues in each eye giving a total of six indicators/cues. Click to see full answer.
What drugs cause HGN?
Horizontal gaze nystagmus causes-drugs and medicines: Nystagmus may be due to causes other than alcohol in three to four percent of the population. Some of these causes include seizure medications, phencyclidine (PCP), barbiturates and other depressants.
What is distinct and sustained nystagmus?
Nystagmus is distinct and sustained when the eye is held at maximum deviation for a minimum of four seconds. The angle of onset of nystagmus is prior to 45 degrees. Based on the original research, if you observe four or more clues it is likely that the suspect's BAC is above 0.10.
What causes horizontal gaze nystagmus?
The forms of nystagmus include:
- Infantile. Most often develops by 2 to 3 months of age. The eyes tend to move in a horizontal swinging fashion. ...
- Spasmus nutans. It usually occurs between 6 months and 3 years of age and improves on its own between 2 and 8 years of age. ...
- Acquired. Develops later in childhood or adulthood. ...
What are the clues for HGN?
Horizontal Gaze Nystagmus Test (HGN) The clues are: lack of smooth pursuit of the eyes, distinct and sustained nystagmus at the eyes' maximum deviation and nystagmus starting before the eyes reach 45 degrees. Keep your head still and follow the stimulus with your eyes only. Do not move your head.
How many passes are in HGN?
The HGN test requires a minimum of 14 passes. Two passes for equal tracking, and four passes each for lack of smooth pursuit, nystagmus at maximum... Thank you for your answer.
What are the 8 clues for the walk and turn test?
The eight clues the officer will be looking for are: not keeping your balance while listening to instructions, starting the test before you are instructed to begin, not touching your heel to your toe, stepping off the line, stopping while walking, using your arms for balance, making an improper tum, and taking more or ...
How many total clues are there that an officer can see during the HGN test?
6The clues are checked for in both eyes of the subject, meaning a total of (6) clues are possible to see during the HGN. Based on validation studies and research officers are trained on, if an officer observes 4 or more clues, it indicates that the person's blood alcohol concentration (BAC) is 0.08 grams or higher.Jan 4, 2017
How do you do Sfst?
Standard Field Sobriety Test (SFST) Guide with CluesRemove glasses/ask if wearing contacts (note type of contacts)Position feet together and place hands at side.Keep head still during test.Follow stimulus with eyes only.Position stimulus 12-15" from person's face in front of the subject's nose slightly above eye level.Jun 26, 2012
Do contacts affect HGN?
Early concerns that contact lenses, especially hard contact lenses, may affect the HGN test result led some to provide for the subject to remove the lenses. However, contact lenses, hard or soft, do not affect the test in any way.
How many clues are there in Sfst?
There are a total of 8 clues the officer is looking for. The police officers are taught that if the person demonstrates 2 or more clues on this test or fails to complete it, then there is a 68% accuracy in determining the suspect's blood alcohol content is above 0.10.Aug 19, 2011
How many clues are in walk and Turn Sfst?
eight cluesThere are eight clues associated with the walk and turn test. Two can be assessed in the “instructional stage” (starts too soon, looses balance) and the remaining six in the” walking stage” (misses heel to toe, steps off line, uses arms to balance, stops while walking, too many steps, improper turn).Jul 27, 2016
How many clues are there in one leg stand test?
four possibleIn the One Leg Stand test there are four possible clues of impairment. If the suspect exhibits two clues then the test results indicate that the person is impaired.
Which drugs cause HGN?
Eye Examination Certain drug categories, such as depressants, inhalants, and dissociative anesthetics, may cause HGN and, in higher doses, VGN.
What are the CLUES 3 and 4?
CLUES 3 & 4: Nystagmus in the right or left eye when moved as far as possible to the right or left (i.e. distinct and sustained nystagmus at maximum deviation).
What is horizontal gaze nystagmus?
Horizontal gaze nystagmus refers to an involuntary jerking of the eyes as the eyes gaze toward the side. In addition to being involuntary, the person experiencing the nystagmus is unaware of its occurrence. 3. The HGN test is one of three standardized field sobriety tests. The other two standardized field sobriety tests are.
Is the horizontal gaze nystagmus test valid?
In California, the horizontal gaze nystagmus test is considered a reliable and valid testing procedure. 14 Hence, HGN test results may be admitted in evidence to corroborate or attack the allegation that a particular defendant had been driving under the influence of alcohol. 15.
Why is the horizontal gaze nystagmus test so difficult?
This is probably the most difficult test to administer because the emphasis is on the officer, not the test subject, to get the test correct.
Why do police use horizontal gaze nystagmus?
Ever since police have used Horizontal Gaze Nystagmus in determining impairment, the defense attorneys have wanted to throw the test out as bunk. This is because they know how damaging good HGN testimony can be to proving impairment. Remember, HGN came to police sobriety testing through medical professionals, and scientists. Testing for HGN is well known and accepted in the scientific and medical community.
What test did the defense use in Frye?
The defense attorneys in Frye had attempted to use an “expert” in deception, using a systolic blood pressure test. The Court properly ruled the technique had not been generally accepted in the medical or psychological professions, so any tests or testimony was properly excluded.
Is horizontal gaze nystagmus influenced by optokinetic nystagmus?
The Horizontal Gaze Nystagmus test will not be influenced by optok inetic nystagmus when administered properly.) Physiological Nystagmus is a natural nystagmus that keeps the sensory cells of the eye from tiring. It is the most common type of nystagmus. It happens to all of us, all the time.
Is HGN a clue?
HGN is a very important clue in DUI investigations, but it is only one of many observations to successfully determine if a driver is impaired and to make a successful case for DUI. Nothing in this article qualifies you to administer the test. You must attend a traditional training course for that.
Does alcohol cause vertical gaze nystagmus?
The presence of this type of nystagmus is associated with high doses of alcohol for that individual and certain other drugs. The drugs that cause Vertical Gaze Nystagmus are the same ones that cause Horizontal Gaze Nystagmus.
What is horizontal gaze nystagmus?
Horizontal Gaze Nystagmus is a series of three tests for the smoothness and accuracy of eye movement control. The eye control becomes visibly disrupted to the examiner when a suspect is impaired by alcohol and/or drugs.
How to move stimulus across the subject's visual field?
Slowly move stimulus across the subject’s visual field, documenting where the nystagmus (eyes tick back) begins. Start with left eye, move the stimulus (at least FOUR SECONDS) from center of subject’s head to the 45 degree angle (approximately the outside of the subject’s shoulder)
How to qualify for HGN?
To qualify as an expert, a police officer must establish the he is qualified by his “knowledge, skill, experience, training or education” to provide expert testimony to “substantially assist the trier of fact to understand the evidence or determine a fact in issue.” Although the court did not rule out the possibility that the officer can be considered an expert, the court set a high level of proof. In this case, the court felt that although the officer had attended law enforcement training in DUI offender apprehension and the HGN test, this training was not enough to establish him as an expert.
What is the DTNH22-92-Y-05378?
This document was prepared under Cooperative Agreement Number DTNH22-92-Y-05378 from the U.S. Department of Transportation National Highway Traffic Safety Administration. Points of view or opinions in this document are those of the authors and do not necessarily represent the official position or policies of the Department of Transportation, American Prosecutors Research Institute or National District Attorneys Association.
How are AGN and PAN different?
In comparing AGN and PAN it is evident that both are caused by alcohol, yet their origins and manifestations are very different.15 AGN is a neurological nystagmus while PAN is a vestibular system nystagmus.16 Unlike AGN, PAN manifests itself only when the subject is lying down, with the head turned to the side and the eyes closed.17 At low intensities, PAN stops when the eyes are open.18 Furthermore, PAN changes direction depending on the position of the head while the direction of AGN depends on the direction of the gaze.19 Because of these differences, officers conducting the HGN test are not likely to confuse AGN and PAN indicators.
Is the HGN test a scientific test?
The majority of state courts hold that the HGN test is a scientific test, resting upon the scientific principle that there is a relationship between alcohol consumption and HGN rather than
Is HGN a field test?
HGN admissible as a field test under the Iowa Rules of Evidence . “[T]estimony by a properly trained police officer with respect to the administration and results of the horizontal gaze nystagmus test are admissible without need for further scientific evidence.” State v. Murphy, 451 N.W.2d 154, 158 (Iowa 1990).
Who is the author of Horizontal gaze nystagmus?
The principal author of this guide is James J. Dietrich, who worked earnestly to identify available resources regarding horizontal gaze nystagmus. Jim undertook this task in his position as staff attorney with the American Prosecutors Research Institute’s (APRI) National Traffic Law Center (NTLC). Janice Frost, NTLC’s senior attorney, contributed her trial expertise in compiling sample predicate questions for this guide to assist prosecutors in preparing cases with HGN issues. The final publication is the result of a collaborative process which drew on the knowledge, expertise and patience of many persons, particularly NTLC’s Director, Patricia Gould, NTLC’s Staff Attorney, Penney Azcarate, NTLC’s Administrative Assistants, Alexia L. Williams and Ruth R. Sanderlin, and APRI’s Director of Management and Development, Heike P. Gramckow.
Is HGN evidence admissible at trial?
To date the courts have determined that HGN evidence does meet Frye and is, therefore, admissible at trial; with one exception. 94 Some courts have held that the prosecution failed to
