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This article
is a condensed version of a paper written in partial fulfillment
of the requirements for the class of Scientific Evidence and Opinion
Testimony during the Winter Semester of 1999 at the UMKC School
of Law. The extensive footnotes have been omitted.
Every
year, tens of thousands of people die in traffic accidents. Alcohol
is a major contributor in traffic fatalities. Alcohol is the most
abused drug in the United States. The name "alcohol" is
given to a family of closely related and naturally-occurring chemicals.
Every chemical called "alcohol" is made up of molecules
that contain a single oxygen atom and differing numbers of hydrogen
and carbon atoms. Ingestible alcohol is known as ethyl alcohol or
ethanol. Ethanol is the active ingredient in beer, wine and liquors
which impairs driving. Approximately 43% of drivers killed in crashes
have been drinking. Alcohol- related crashes are about nine times
more likely to result in death than crashes without alcohol involvement.
After drinking, drivers are more likely to take excessive risks,
like speeding. Additionally, drinking drivers are more likely to
have slowed reaction times resulting in the inability to slow down
before crashing. Two percent of drivers, on average, on the road
at any given time and driving while intoxicated.
To
combat the serious consequences of driving under the influence,
the National Highway Traffic Safety Administration ("NHTSA")
has developed a battery of field sobriety tests, which are designed
to detect the impaired driver. NHTSA considers the tests "the
most effective procedure[s] for testing drivers at roadside to determine
whether or not they are intoxicated." Many of the most reliable
and practical psychophysical tests use the concept of divided attention.
Divided attention requires an individual to concentrate on two things
at once. Driving is an example of a divided attention task. A driver
must simultaneously control steering, braking and acceleration,
and react appropriately to changing conditions in order to operate
a vehicle safely. Alcohol significantly reduces persons' ability
to divide their attention between tasks. Even while under the influence,
many people can handle a single, focused attention task fairly well,
but cannot satisfactorily divide their attention to handle multiple
tasks at once. Field sobriety tests that simulate the divided attention
characteristics of driving are being used by police departments
nationwide. The best tests use the same mental and physical capabilities
that a person needs to drive safely: information processing; short-term
memory; judgment and decision making; balance; steadiness, sure
reactions; clear vision; small muscle control; and coordination
of the limbs. Two divided attention field sobriety tests that have
been proven accurate and effective in DWI Detection are the Walk-and-Turn
and the One-Leg Stand.
An additional test is the horizontal gaze nystagmus ("HGN").
When used in combination with divided attention tests, HGN helps
police officers correctly distinguish suspects who are under the
influence of alcohol from those who are not. The test is based on
the fact that alcohol affects the automatic tracking mechanisms
of the eyes. Nystagmus is defined as "an involuntary rapid
movement of the eyeball, which may be horizontal, vertical, rotatory,
or mixed." Alcohol slows down the eyes' ability to rapidly
track objects and causes to eyes to oscillate, or "jerk",
before they normally would in a sober person. Alcohol stimulates
the nerve endings, making nystagmus more pronounced in intoxicated
persons. As a person's blood alcohol concentration increases, the
eyes will "jerk" sooner as they move to the side. The
HGN test claims to gauge intoxication by measuring the involuntary
oscillation of the eyes.
The
procedure to be used by police officers is set out by the National
Highway Traffic Safety Administration in the DWI Detection and Standardized
Field Sobriety Testing Student Manual. Prior to administration of
HGN, the eyes are checked for equal tracking ability and equal pupil
size. If the eyes do not track together or if the pupils are unequal
in size, injuries or medical disorders are likely the cause of the
nystagmus. The NHTSA standardized clues include lack of smooth pursuit,
distinct nystagmus at maximum deviation and onset of nystagmus prior
to reaching a 45 degree angle. Standardized administration procedures
include: holding the stimulus 12-15 inches in front of the suspect's
nose; keeping the tip of the stimulus slightly above the suspect's
eyes; always moving the stimulus smoothly; always checking for all
three clues in both eyes; starting with suspect's left eye; checking
the clues in sequence: (1)lack of smooth pursuit, (2) distinct nystagmus
at maximum deviation, (3) onset of nystagmus prior to 45 degrees;
always checking for clues at least twice in each eye. The NHTSA
manual indicates that no other "clues" are recognized
by the NHTSA as valid indicators of HGN. In particular, the NHTSA
does not support the allegation that onset angle can reliably be
used to estimate BAC, and considers any such estimation to be misuse
of the horizontal gaze nystagmus test. The NHTSA sets forth standardized
criteria for evaluating HGN. The maximum number of clues of horizontal
gaze nystagmus suspect can exhibit is six, occurring if the suspect
exhibited all three clues in each eye. If a suspect exhibits four
or more clues, it should be considered evidence that the suspect's
BAC is above .10.
Nystagmus
may be caused by many other factors. The court, in State v. Witte,
251 Kan. 313, 326, 836 P.2d 1110, 1119 (1992) said:
Nystagmus can be caused by problems in an individual's inner ear
labyrinth. In fact, irrigating the ears with warm water or cold
water...is a source of error. Physiological problems such as certain
kinds of diseases may also result in gaze nystagmus. Influenza,
streptococcus infections, vertigo, measles, syphilis, arteriosclerosis,
muscular dystrophy, multiple sclerosis, Korsakoff's Syndrome,
brain hemorrhage, epilepsy, and other psychogenic disorders all
have been shown to cause nystagmus. Furthermore, conditions such
as hypertension, motion sickness, sunstroke, eyestrain, eye muscle
fatigue, glaucoma, and changes in atmospheric pressure may result
in gaze nystagmus. The consumption of common substances such as
caffeine, nicotine, or aspirin also lead to nystagmus almost identical
to that caused by alcohol consumption. (Quoting Pangman, Horizontal
Gaze Nystagmus: Voodoo Science, 2 DWI J. 1, 3-4 [1987])
Also,
a individual's circadian rhythms or biorhythms can affect nystagmus
readings. The body reacts differently to alcohol at different times
in the day. Taking this into consideration, one researcher suggests
the angle of onset should be decreased five degrees between midnight
and 5 a.m. Rouleau, 4 Am.Jur. Proof of Facts 3d 439 § 9, p.
456; Pangman, 2 DWI Journal at 3.
The
NHTSA manual recommends removal of all contact lenses. In addressing
non-alcohol causes of nystagmus the manual only notes, "[n]ystagmus
may be due to causes other than alcohol in three or four percent
of the population." Critics argue that with the numerous causes
of HGN listed above, that the instances of non-alcohol related HGN
is greater than three to four percent. In 1990, the United States
population was 248.71 million people. During that year, 22 million
(8.4%) wore contact lenses. This alone indicates that significantly
more that three to four of the population may have nystagmus unrelated
to alcohol.
Conflict
begins to arises when courts are asked to determine the admissibility
of novel scientific evidence such as HGN. Initially, the court must
ask if evidence is relevant. To be relevant, evidence must be probative
of a material fact. If deemed relevant, the court must address whether
the jury is familiar with the underlying science, as well is determine
whether the "science" is valid. Most jurors are not familiar
with HGN, requiring expert testimony to aid the jury in determining
the test's probative value. Two main approaches have been taken
in evaluating the validity of expert evidence on HGN.
"General
acceptance" was established as the test in Frye v. United States,
293 F. 1013, 1014 (D.C. Cir. 1923), a case which involved the admissibility
of polygraph tests:
Just when a scientific principle or discovery crosses a line between
the experimental and demonstrable stages is difficult to define.
Somewhere in this twilight zone the evidential force of the principle
must be recognized, and while the courts will go a long way in admitting
expert testimony induced from a well-recognized scientific principle
or discovery, the thing from which the deduction is made must be
sufficiently established to have gained general acceptance in the
particular field in which it belongs.
In
recent years, the United States Supreme Court has held that the
Frye standard does not apply to the admission of scientific evidence
in federal courts. The Court held that the Frye standard had been
superseded by the passage of Federal Rule of Evidence 702 and that
proof of scientific validity is to be the standard of admissibility.
Daubert v. Merrell Dow Pharmaceuticals, 113 S. Ct. 2786 (1993).
The decision set forth the following procedure to determine validity:
Faced
with a proffer of expert scientific testimony, then, the trial judge
must determine at the outset, pursuant to Rule 104(a), whether the
expert is proposing to testify to (1) scientific knowledge that
(2) will assist the trier of fact to understand or determine a fact
in issue. This entails a preliminary assessment of whether the reasoning
or methodology underlying the testimony is scientifically valid
and of whether that reasoning or methodology properly can be applied
to the facts in issue. Id. at 2796.
The
Daubert court then suggested the trial judge consider several factors
when determining the admissibility of expert testimony: (1) whether
the evidence has been tested by scientific methodology, (2) whether
the underlying theory or technique has been subject to peer review
and has been published in professional literature, (3) how reliable
the results are in terms of potential error rates and (4) general
acceptance. Id. at 2796.
Continuing
debate on the differences between the two approaches--Frye and Daubert--has
been noted and numerous state courts continue to use the Frye test
despite possessing evidence rules patterned after the Federal Rules
of Evidence. Additionally, the tests are not mutually exclusive.
Under Daubert, general acceptance remains one factor probative of
validity. Application of either the Frye or the Daubert test can
lead to differing opinions on admissibility of HGN testimony.
Research
on HGN is limited. Only three published studies have tested HGN
as a field sobriety test. The Southern California Research Institute
(SCRI) study, entitled Development and Field Sobriety Tests of Pyschophysical
Tests for DWI Arrests, DOT-HS-805-864 (1981) was commissioned by
the National Highway Traffic Safety Administration. The study included
a laboratory and field component. Due to lack of cooperation and
poor performance by participating officers, SCRI concluded the field
study data was not worthy of statistical analysis. After training,
the control group arrested 28.6 percent of "stoppees"
with BACs between .05 percent and .099 percent, while arrest rates
in for other BACs remained the same. Therefore, officers made the
wrong decision to arrest almost 30 percent of the time. This leads
to the conclusion that arrests made based on HGN in suspected zone
of .05 to .099 BAC are the most likely to produce most decision
errors. SCRI recommended that a major effort was needed for a new
field evaluation: "Extremely serious problems result when there
is a lack of interest and cooperation by individual officers, by
supervisory personnel, or by agencies."
The
NHTSA then performed another study, Field Evaluation of a Behavioral
Test Battery for DWI, DOT-HS-806-475 (1993). Officers from four
different states were instructed to administer the test battery
(walk-and-turn, one-leg-stand and horizontal gaze nystagmus) and
also to administer a preliminary breath test (PBT) to every stoppee.
The report did not specifically provide data on HGN, but reported
on the combined procedure. NHTSA claimed an accuracy rate for the
combined procedure of 82 percent, with 16 percent false positives
and 1 percent false negatives. The NHTSA's report cautioned against
using the data as indicative of the accuracy of the tests because
only stoppees asked to participate in breath tests were included
in the data. This factor makes the group sample biased toward high
BAC levels because it did not include all stoppees, it included
only those actually arrested. Additionally, the study did not provide
the actual BAC of those arrested. Without knowing the sample distribution,
any accuracy rate becomes suspect, particularity when the probability
of error is greatest near the legal limit.
A third
study was conducted by George Golding and Robert Dobie, Gaze Nystagmus
and Blood Alcohol, 96 LARYNGOSCOPE 713 (1986). It evaluated 159
DWI suspects and 46 emergency room patients. Seattle Police officers
performed the field evaluation to only those they suspected of driving
under the influence of alcohol, again biasing the data towards high
BACs. Eight of the 159 had a BAC of less than .10, three of which
the officers classified as legally intoxicated.
Researchers
have conclude that the percentages generally cited by court opinions
in support of HGN only exist in NHTSA publications. Joseph R. Meaney,
Horizontal Gaze Nystagmus: A Closer Look, 36 Jurimetrics J.383,
385 (1996). The figures have not been duplicated in field study.
The three studies all conclude that HGN can help officers decide
whether a stop is a good candidate for arrest and subsequent chemical
testing. The three tests also conclude that HGN should only be used
as a tool raising or lowering suspicion of a person's sobriety.
Officers in the field have not been able to show that they can correctly
identify those drivers with actual BACs in the critical range of
.05-.15 percent.
The
NHTSA states that if nystagmus is observed at the 45 degree angle,
a BAC of .10 can be correctly estimated 77 percent of the time.
Alternatively, this indicates that results of HGN are incorrect
23 percent of the time. One researcher indicates that 50-60 percent
of sober individuals who deviate their eyes more than 40 degrees
to the side will exhibit nystagmus, and this type of nystagmus is
indistinguishable from alcohol induced nystagmus. Pangman, 2 DWI
Journal at 2 (citing Toglia, Electronystagmography: Technical Aspects
and Atlas [1976]).
Several
courts have taken these concerns regarding the scientific basis
and validity of HGN, peer review, error rates and general acceptance
into consideration when determining whether its admissibility as
scientific evidence. In Witte, the court held that HGN test results
could not be admitted into evidence at a DUI trial because the Frye
standard had not been met. State v. Witte, 251 Kan. 313, 836 P.2d
1110 (1992) Oklahoma courts agreed, stating HGN does not met Frye
requirements. See Yell v. State, 856 P.2d 996 (Okla. App. 1993).
The Criminal Court of Appeals in Oklahoma stated "a review
of the record in the present case reveals that there was absolutely
no evidence that the reliability of the HGN test has gained acceptance
in the concerned scientific community." In State v. Borchardt,
395 N.W.2d 551 (Neb. 1986), the court came to a similar conclusion.
The court held that it was error to admit HGN test results into
evidence at a DUI trial because the state had not established the
scientific reliability of the test by laying a proper foundation.
By
contrast, the majority of states seems to accept HGN testimony.
One court held that acceptance was predicated on general acceptance
within the relevant scientific communities of optometry, neurology,
behavioral psychology, highway safety and forensic science. State
v. Carlson, 45 Conn.Supp. 461, 720 A.2d 886 (1998). Another court
held simply that HGN testimony was not "scientific" evidence,
therefore did not need to satisfy Frye criteria, and results of
the test were admissible the same as evidence of other field sobriety
tests, such as finger-to-nose, or walk-and turn results. State v.
Bresson, 51 Ohio St. 3d. 123, 554 N.E.2d 1330 (1990).
Perhaps
the best approach to the dilemma of the non-existent proof of reliability
of the determination of a specific blood-alcohol level by HGN is
to admit the evidence, assuming the test was conducted in the prescribed
manner by a properly trained police officer, to show impairment,
but not as evidence of a specific blood-alcohol level.
Editor
AN ADDITIONAL CASE MENTIONED:
On
March 10, 2000, the Supreme Court of Nebraska, in State v. Baue,
258 Neb. 968 (2000) held that the results obtained through the horizontal
gaze nystagmus (HGN) field sobriety test were admissible for the
limited purpose of establishing that the defendant had an impairment
which could have been caused by alcohol. In so doing, the Court
overturned the State v. Borchardt decision mentioned in the above
article.
At
the trial in Baue, the state had called three experts. One was a
research psychologist who had testified on HGN testing in approximately
26 jurisdictions and who had participated in studies leading to
formulation of the 1977 and 1981 NHTSA reports. She had also participated
in a field study for the Colorado Bureau of Transportation in 1995.
She testified that the HGN test "is a valid and reliable means
of determining alcohol impairment." Another expert was an optometrist
and professor of optometry who testified that HGN is intended to
identify an impairment which may be caused either by alcohol or
by other causes, but that performance on the HGN test does not of
itself prove that the subject is intoxicated. The third expert was
the director of training for the Nebraska State Patrol, the agency
that trains officers in field sobriety testing. He, too, was of
the opinion that the test was "a reliable indicator of impairment"
caused by alcohol or other factors.
Based
upon its review of the evidence, the Supreme Court of Nebraska concluded
"that the basic scientific principle upon which the HGN field
sobriety test is based, i.e., that alcohol consumption causes nystagmus,
is generally accepted in the relevant scientific community."
The court agreed, however, that because nystagmus may also be caused
by other factors, intoxication cannot be established by HGN results
alone. Further, the court stated that the HGN field sobriety test
is admissible only for the limited purpose of establishing that
a defendant has an impairment which may be caused by alcohol.
The
court further held, in accord with the majority of jurisdictions,
that "a police officer may testify to the results of HGN testing
if it is shown that the officer has been adequately trained in the
administration and assessment of the HGN test and has conducted
the testing and assessment in accordance with that training."
No additional foundational evidence on the scientific principles
and theory underlying HGN is required.
©
2000 HoltLawFirm, Inc. All rights reserved.
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