Children and adolescents who are not doing
well in school and who are manifesting symptoms
of inattentiveness, distractibility,
hyperactivity, disorganization, and poor
continuous task performance frequently receive
the diagnosis of attention deficit-hyperactivity
disorder. We present diagnostic criteria and
representative cases illustrating a condition
that we have designated as primary disorder of
vigilance. This disorder can be included in the
spectrum of specific conditions having
characteristic symptoms that overlap the
criteria for attention deficit-hyperactivity
disorder.
DEFINITIONS
Vigil ance is steady-state alertness,
wakefulness, and arousal-the state of being
watchfül, awake, and alert.1 We have noted
families in which the major symptoms relate to a
basic disturbance in vigilance.2,' Such problems
as poor sustained attention, trouble
concentrating, and difficulty staying awake
(drowsiness or sleepiness) can be the result of
disturbed vigilance. Diagnostic criteria for the
primary disorder of vigilance, established on
the basis of a typical cluster of symptoms seen
in affected children and their family members,
are presented in Table I.
We believe that this condition is a major cause
of school failure, results in conflicts between
child and parent, and is associated with
difficulties in work adjustment and enjoyment of
life. If not recognized and properly treated,
the primary disorder of vigilance can be
severely incapacitating, and the associated
accident proneness can even become fatal. Table
II prescrits a summary of six representative
patients who fulfill the diagnostic criteria
listed in Table I, and shows the coincidence of
this condition with other common childhood
disorders, including depression and epilepsy.
Patient 1 is reported in detail.
CASE REPORT
Patient 1, a boy born after a prolonged labor
with a birth weight of 3600 g, had a normal
early infancy except for mild colic and was
described as a "good infant." He sat at 8
months, walked at 17 months, and rode a tricycle
at 5 years and a bicycle at 7 years. He began
talking at about 3 years of age and was toilet
trained at 4 years of age. Despite these delayed
developmental milestones, he did well in nursery
school and kindergarten. At the age of 7 years 5
months, the Wechsler Intelligence Scale for
Children, Revised Edition (WISC-R), showed the
following scores: Verbal IQ 128 (subtest scores:
Information 13, Comprehension 15, Arithmetic 14,
Similarities 12, Vocabulary 15, Digit Span 8),
Performance IQ 105 (subtest scores: Picture
Completion 11, Picture Arrangement 12, Block
Design 12, Object Assembly 13, Coding 6), and
Full Scale IQ 117. However, elementary school
teachers described him as slow moving, a
dawdler, a procrastinator, not competitive,
immature, a "daydreamer" with poor attention,
easily distracted, lazy, and wanting to avoid
work. He was also described as kind,
affectionate, compassinate, sensitive to the
feelings of others, and a "very good child" who
was never a behavior problem. He enjoyed asking
questions and telling long stories with great
detail.
He was first evaluated at the age of 8 years
9 months, at which time he described himself as
restless, needing to move his legs to keep
himself from falling asleep. He yawned a
lot in school, found school boring, voluntarily
avoided doing things in school because such
tasks produced boredom and sleepiness, and
daydreamed to keep from being bored. He said
reading was boring and put him to sleep, and he
complained that his thoughts would wander,
making it difficult to keep to a task. The
mother reported that he would sleep 12 hours at
night and still take a 2-hour nap during the
day. He was very sleepy in the morning on
arising, and his mother had to coax him to get
up (otherwise he would sleep beyond 10 AM) and
cajole him to dress (often he took 30 minutes to
put on his shoes). He was accident prone, having
sustained fractures of humerus and the clavicle.
He experienced no hypnagogic hallucinations,
sleep paralysis, or cataplexy.
The family history was remarkable for the
mother's sleeping 12 to 14 hours at night, along
with having problems of poor concentration and
difficulty staying awake when not busy. She
complained of being bored and sleepy when riding
in a car, reading a book, or sitting in a
lecture hall or church, and indicated that she
most enjoyed busy activities. A maternal aunt,
maternal first cousin, maternal grandmother, and
maternal great-grandmother had similar
symptoms.
The patient was treated with methylphenidate
(20 mg sustained-release tablet each morning) at
the age of 8 years 9 months, with immediate
improvement; he described himself as alert, his
grades in school improved markedly, and he slept
for only 10 hours a night, with no daytime
napping. During a 4-month period he read 59
books (and received a trophy from the school for
this achievement). He was able to sustain
attention to tasks both in school and at play;
for example, he built a model of the Hoover Dam
out of 25,000 toothpicks, working incessantly on
this project for several days. It was noted by
the mother and teachers (as well as by the child
himself) that as the methylphenidate effect wore
off, he would become sleepy and restless, would
daydream, would have difficulty concentrating,
and would become sleepy after lunch, while
riding in a car, and when still (sitting at a
table, watching television, or listening to a
discussion). His methylphenidate dosage was
adjusted during the following 21 months to 40 mg
at 7 AM, 40 mg at noon, and 20 mg at 4 Pm. This
dosage provided an optimal subjective feeling of
alertness, observed wakefulness, and improvement
in his school performance and play (he became a
competitive Little League football player).
Multiple trials of periods without the use of
methylphenidate resulted in his becoming sleepy,
irritable, easily frustrated, and restless, with
deterioration of his school performance and of
his interest in play. He reported that he could
not concentrate and stated that the
methylphenidaie was necessary keep my brain
awake!"
At the age of 12 years 3 months, the patient
discontinued the methylphenidate regimen for the
2 weeks before formal sleep studies. Without
medication, he was sleepy during the day, very
restless ("hyperactive"), unable to sustain
attention, and irritable, and he had difficulty
falling asleep at night. On the Stanford
Sleepiness Scale, he endorsed items indicating
severe sleepiness and described himself as
fighting off sleep, being woozy in the morning,
and being only somewhat alert by late afternoon.
Polysomnography showed an entirely normal sleep
pattern. On the multiple sleep latency tests,
with five opportunities every 2 hours to fall
alseep, he slept during the first test period at
9 AM (not associated with rapideye-movement
sleep) but not during the other opportunities.
During the Multiple Vigilance Test, he looked
away from the screen much of the time, made a
large number of errors, and was impulsive in his
responses. After hospital discharge,
methylphenidate therapy was restarted, with
continued good response and no apparent side
effects or loss of effectiveness. In addition,
his mother noted a marked improvement in her
alertness and ability to concentrate after she
began taking methylpheniate, 40 mg at 7 Am and
20 mg at noon.
DISCUSSION
Persons with primary disorder of vigilance
are unable to maintain alertness and
wakefulness, and this inability results in
symptoms indicating a short attention spart,
poor concentration, and problems in appearing
and being awake. The diagnostic criteria for
this disorder provide the minimal symptoms found
in affected persons. The most obvious evidence
that the patient is having difficulty staymg
awake and alert is the frequent fidgeting,
yawning, and stretching when sitting still.
In various tasks requiring continuous mental
performance, the person complains of having
trouble concentrating and being bored by the
monotony, loses interest, and often does not
complete the task. A child with the disorder may
resist homework because of difficulty in staying
alert during the required continuous mental
performance. Thus homework can become a major
source of confrontation between child and
parent. Affected children may be quick to start
new activities but will rapidly tire of thent
and quit. They appear disorganized, and imposing
excessive structure, sameness, organization, or
repetitive activity on them results in poor
performance. When participating in highly
repetitive activities or activities requiring
continuous mental performance or continuous task
performance, these children are restless,
fidgety, or talkative, or they move and walk
about in an apparent attempt to maintain
vigilance. If prevented from being active (for
example, in church, in school classes, at the
dinner table, or strapped in a seat belt while
riding in a car), they will stare off, daydream,
show minor restlessness, yawn and stretch, and
finally may fall asleep.
The primary disorder of vigilance appears to
be a lifelong condition that results in varying
behaviors at different ages. Difficulties with
attention begin to be evident in structured
preschool programs. School is characterized by
teacher reports of inattentiveness, daydreaming,
not completing assigriments, and disruptive
behavior characterized by talking, fidgeting,
squirming, and moving about. On the playground
and after school, these children are busy and
active in play. There is increased resistance
toward homework as the volume of routine,
repetitious material increases. When trying (or
forced) to sit at a desk and do homework, the
affected child or adolescent will stare off into
space, daydream, gel up and move about, and
spend an inordinate amount of time attempting to
complete a task. Affected persons eventually
begin to drop out of structured or repetitive
activities and pursue activities and work that
are characterized by variety (specifically,
activities with random variation in routine,
i.e., "orderly randomization"). Most resist
reading, attending lectures, watching
filmstrips, and writing essays, because these
activities promote tedium ("boring,"
"monotonous," "uninteresting"). When asked
directly, they will also indicate that they have
trouble with concentration and attention,
daydreaming, and feeling sleepy. Affected adults
may deny sleepiness but readily admit to boredom
in tasks that are repetitious or require
continuous mental performance, and they often
diligently avoid such activities. The affected
adult commonly falls asleep ("catnaps") when
still (such as while attending church, watching
television or a bail garne, riding in a car, or
reading), but the naps are not refreshing.
Affected persons are often teased by family
members about these naps. Elderly persons may be
described as "sleeping the remaining years
away."
An intriguing and important characteristic of
persons with the primary disorder of vigilance
is a kind, caring, compassionate, and
affectionate temperament. These children and
adolescents never have evidence of conduct
disorder and rarely have discipline problems.
Affected infants enjoy being field, cuddled,
nursed, and loved. Preschool and elementary
school children are usually well liked by their
teachers and peers. Although middle school and
junior high school children may be exasperating
to parents and teachers, they remain
affectionate, caring, kind, and generous in
their compassion for the unfortunate. This
"angelic" nature persists into adulthood.
The mechanism of vigilance is unknown and
thus the genesis of disturbances of vigilance is
speculative. Studies in physiologic psychology
have defined vigilance as sustained attention.
Available tests used to assess vigilance
actually measure sustained attention. No
currently available procedures measure pure
vigilance, which is the positive ability to stay
wakeful, alert, or awake on tasks requiring
continuous mental performance. Vigilance is
considered to be a major component of the
network of sustained or directed attention (or
the "attentional matrix"), which also includes
affect, memory, motivation, and perception.
Vigilance is possibly a right cerebral
hemisphere (posteroinferior parietal lobe)
function. When the attentional matrix is
discussed, words such as "concentration,"
"perseverance," "alertness," and "vigilance" are
used synonymously to describe positive aspects
of attention, whereas "comatose," "stuporous,","
sleepy," and "drowsy" are used as a hierarchical
schema to denote decreased (negative) levels of
attention. We suggest that with the loss of
vigilance, there is diminished ability to
maintain an alert, awake state. If not allowed
to move, fidget, daydream, or be free of tasks
requiring continuous mental performance (or
repetitiveness), the cerebral alerting necessary
to prevent sleep is readily overcome and
brainstem-induced sleep ensues.
Children, adolescents, and their parents who
manifest the primary disorder of vigilance are
free of the rapid eye movement-associated
symptoms of hypnagogic hallucinations, sleep
paralysis, and cataplexy, and they have none of
the narcolepsy findings obtained from
polysomnography, multiple sleep latency tests,
and tests of the DR2 locus of the human
leukocyte antigen. We have seen several families
that have both narcolepsy and the primary
disorder of vigilance in different individuals,
and one young person with both problems. In an
evaluation of vigilance, secondary causes of
lowered vigilance must also be excluded.
Depression metabolic disorders (such as
hypothyroidism and hypoglycemia), seizure
disorders, and the use of illicit drugs and
various medications can all reduce vigilance. In
particular, commonly used anticonvulsant agents,
antihistamines, and both minor and major
tranquilizers often lower vigilance to the point
of causing clinical concern. In a recently
studied group of 100 consecutive children and
adolescents (aged 3 to 17 years) referred to the
Children's Medical Center of Dallas Pediatric
Behavioral Neurology Program, 47 had evidence of
lowered vigilance. Of these, 23 fulfilled the
criteria for primary disorder of vigilance; the
other 24 had sorne other cause for disturbed
vigilance.
The primary disorder of vigilance appears to
be a dominantly inherited condition that is
lifelong and that worsens with age. Although it
is the children and adolescents who may be
brought to clinical attention, their affected
parents, grandparents, and other relatives
usually go unrecogized. An adult having
difficulty with continuous mental performance
and continuous task performance should also be
evaluated for this treatable condition. The
excessive somnolence may not be bothersome in
and of itself, but the consequences of this
disorder can be devastating, including failure
in school and in the workplace. Accidents are
more likely because of delayed reaction time and
falling asleep in dangerous situations (such as
driving a car). If the primary disorder of
vigilance is recognized and appropriately
mariaged, the affected person may be spared much
discomfort.
Treatment of this disorder with a stimulant
medication, either methylphenidate or pemoline,
is often successful when the person is free of
depression (Figure). If depression is present, a
tricyclic antidepressant agent is necessary
(preferably without methylphenidate or pemoline)
until depression has lifted. The less sedative
antidepressant agents seem most effective
(imipramine, desipramine, and protriptyline, in
that order). Management must also include the
offering of instruction and practice in the
context of orderly randomization rather than
structured repetition, reiteration, and
excessive drill, which lower vigilance (creating
boredom, monotony, and the feeling of
sleepiness). Short breaks should be built into
the scheduling of tasks, the number of items per
task should be limited, and scheduled events
should change frequently (preferably in
randomized fashion).
REFERENCES
