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(Received October 28, 1968; revision accepted for publication March 25, 1969.) This work was supported by a Grant from the Vancouver Foundation.

ADDRESS: (J.U.C.) Department of Paediatrics, 715 West Twelfth Avenue, Vancouver 9, British

Columbia, Canada.

365

A

CLINICAL

APPROACH

TO

THE

MEASUREMENT

OF

CEREBRAL

DYSFUNCTION

John U. Crichton, M.B., M.R.C.P.(E), and Harley P. Mackoff

Department of Paediatrics, University of British Columbia, Vancouver, British Columbia

ABSTRACT. Cerebral dysfunction is seldom

mea-sured by objective means. Previous attempts to do so have mainly been concerned with abnormalities

of motor behavior, though some attempts at

mea-surement of attentional factors have been made.

Because oculomotor hyperkinesis might involve

both these facets of cerebral dysfunction,

electro-oculography was used in the present study to record

eye movements in different groups of subjects.

Twenty-five children aged 6 to 12 years with no

known neurological disease, 25 children aged 5 to

11 years with minimal cerebral dysfunction, and

16 children aged 5 to 14 years with more gross

forms of neurological disease were tested.

The ability of these children to fix a target

vis-ually over a period of 120 seconds (when a visual distraction was provided) was found to distinguish

normal children from those with cerebral dysfunc-tion when the total duration of fixation on the

tar-get was used as a measurement. The duration of

the first fixation was statistically significanfly longer and the number of discrete fixations was signifi-candy fewer in the normal children, but the range of measurements was too great for these variables to be of use in an individual case. Among normal children, ability to attend to the task was found to improve with increasing age, and girls were found to be better performers than boys of the same age.

The method is potentially useful not only as a

diagnostic aid but also in the assessment of prog-ress, whether the children are treated or not.

Pedi-atrics, 44:365, 1969, ATfENTION, CHRONIC BRAIN

DAMAGE, ELEcTRO-OCULOCRAPHY, MOVEMENT

DIS-ORDERS-HYPERKINESIS.

I

N minimal cerebral dysfunction, as in

other conditions, the behavioral mani-festations are usually described in clinical

terms but not expressed in any objective

terms of measurement. Stevens, et al.1

de-vised a battery of tests related to the motor

and perceptual skills of the children, and

this battery could be used in distinguishing children with minimal cerebral dysfunction

from a group of normal controls. Their tests

did not measure pure factors and involved

motivation, perception, and attention in

most instances. These measurements are

concerned with various aspects of skills

which may be affected by minimal cerebral

dysfunction, but others have attempted to

measure spontaneous motor activity. The

following techniques have been used:

1. Ounsted2 recorded, by admittedly

crude means (i.e., timed clinical observa-tions), the spontaneous activity of

hyperki-netic epileptic children and attempted to

quantify it. Later, his co-workers (Hutt, et

al.3) devised a system for scoring the

be-havior of children in a “free-field” setting;

an observer recorded the behavior of the

child on tape (using a stylized dictation),

and this was subsequently analyzed.

2. A school desk with modified

ballisto-cardiograph has been used by Foshee to

measure total body movement of a subject

during performance of a set task.

3. Ellis and Pryer5 devised a special

room in which the moving child, by

break-ing light beams from photoelectric cells, ac-tivated a counting mechanism.

4. Schulman and Reisman#{176} developed

the actometer-a device by which a limb

activates the self-winding mechanism of a

watch modified to score the activity in

terms of a period of time. Such devices

were later used by Millichap and Boldrey7 in a controlled study of the effect of drugs on the condition, but these devices are ex-pensive and difficult to obtain.

Increased motor activity in minimal

(2)

I)ala

Number of Children

rouj A Group B Group (I

22 ‘25 23 16 15

Average age 9 yr, 1 mo 8 yr. 8 mo 7 yr, 10 mo 7yr, 8 mo 9 yr, 3 mo 8 yr. ii me

Age range 6-12 yr 6-12 yr 5-11 yr 5-11 yr 5-14 yr 5-14 yr

Average total duration of fixation (sec.)

Range

112.9

95.9-120

112.5 95.9-120

72.7 0-116.6

73.6 24.8-116.6

75.2

12.9-118.8

72.6 12.9-118.8

Averagefirstfixation(sec.)

Range

38.2

1.0-120

36.2

1.0-120

8.6 0-93.3

8.9 0-93.3

12.0

0-53 .0

9.8

0-53.0

6.0 6.3 11.5 11.9 11.4 11.7

1-13 1-13 3-22 2-22 2-21 2-21

Eyes UpEyes Down Eyes to Right Eyes to Left

3

Fic. 1. Electrooculogram: eye movements performed on request. Average number of

fixations Range

TABLE I

AVERAGE VALUES

Figures in italics represent those used for statistical purposes to control age factor.

bral dysfunction is closely associated with

changes in attention, namely,

impulsive-ness, distractability,#{176} and reduction of at-tention span itself. One aspect of particular

#{176}Distractability: a manifestation of

uncontrol-lable hyperresponsiveness to external stimuli

(Browning’).

interest is oculomotor hyperkinesis and

motor impersistence of the eye muscles. If

there is a connection between oculoniotor

hyperkinesis and generalized hyperkinesis,

this might at least account for the

short-ened attention span in hyperkinetic

chil-dren. One of the variables observed by

#{149}#{128}J( #{149}

2

#{149} #{149}- 4p

3

cT

(3)

ARTICLES

* Figures are calculated on the sample excluding for statistical analysis subjects at extremes of age (italics).

n.s. = not significant.

Hutt, et al. was visual fixation

(

defined as fixations which lasted 1% seconds or more). The duration of these fixations varied in the normal children in a manner commensurate with their surroundings, but in the

brain-damaged group it tended to be

compara-tively inflexible and unrelated to any

envi-ronmental change. These authors also

found that attention span (defined as the

duration of serial contact with the same

stimulus irrespective of how these contacts

were made) in brain-damaged children

varied little in different environmental cir-cumstances, whereas it would vary

accord-ing to the complexity of the environment in

normal children.

In the course of clinical examination of

children with cerebral dysfunction, as with

young children, it is commonly observed

that ophthalmoscopic examination is

diffi-cult because the child tends to look directly

at the ophthalmoscope light, despite

in-structions to the contrary. It was thought

that measurement of such a tendency might

be a valid measure of the degree of

abnor-mality present, whether it be thought of as

hyperkinesis of the ocular musculature, lack

of attentiveness, distractability,

impulsive-ness, or motor impersistence. Accordingly, a

simple clinical test was devised in an

at-tempt to measure these manifestations of

minimal cerebral dysfunction; a deliberate

TABLE II

SEX DIFFERENCE: STATISTICAL ANALYSIS5

Data Male Female Value

Group A Normal

number of children 12 12 13 10

average total duration offixation averagefirstfl.xation time averagenumberof fixations average age 110.lsec 30.3 sec 6.9 8 yr, 2 mo

11O.lsec

30.3 sec 6.9 8 yr, 2 mo

115.2sec 45.6 sec

5 9 yr, 1mo

115.2sec 48.2 sec

5.4

8 yr, 6 mo

t=1.62pn.s.

t=0.74n.s. t=1.25n.s.

t =0.65 n.s.

Group B minimal cerebral dysfunction

number of children 19 18 6 5

average total duration of fixation

average first fixation time

average number of fixations average age

78.9 sec 9.5 sec 12.6 7 yr, 11 mo

73.4 sec

9.5 sec

11.6

7 yr, 10 mo

70.6 sec 6.0 see 13.1 7 yr, 11 mo

74.4 sec 7.2 sec

12.8 8 yr. 5 mo

t= -0.07 n.s. t= -0.23 n.s. t= -0.50 n.s. t= 0.77 n.s. Group C other

neurological disease

number of children 10 9 6 6

t= -1.46 u.s.

t= -1.79 p 0.1

t=0.3n.s.

t= 0.27 n.s. average total duration

of fixation

average first fixation time

aserage number of

fixations average age

84.6 sec 15.3 sec

10.4 9 yr, 3 mo

81.4 sec 18.5 sec

10.8

8 yr. 9 mo

59.4 sec 6.5 sec

10.9 9 yr, 1 mo

59.4 sec

6.5 sec

(4)

3

T.C. 0.3

1 sec.

oo

C

o

GROUP

A

Normal

GROUP

B

-

MCD

#{163}

GROUP

C

-

Other

Neurological

Problems

O 0 0

0 0

0

U 0 000

U

U

0

U 0

U

4

U

#{163}

0

U #{163}

In

120

z

O

110-

I-<

100->< 9

#{176}80-z

070-

I-<

60-c

50--J

<

40-

230-0 0

0 0 0 0 U .0 U

U

#{163}

U

*

#{163}

0

#{163}

U

#{163}

#{163}

0 7

I U U

8 9 10

AGE

(YRS.)

11 12 13

Fic. 3. Graph showing total duration of fixation plotted against age in normal and abnormal children.

CEREBRAL DYSFUNCTION

>

1. 0

0

.. 2

#{149}!bg.

3

#{149}#{149}Zl:O_l\#{149}(41>#{243}

Fic. 2. Electrooculogram: sample trace of random eye movements mary stimulus.

(5)

pri-ARTICLES 369

TABLE III

STATISTICAL SIGNIFICANCE OF AVERAGE VALUES

S mple

Group B Group C

Total Duration Duration of Number of

of Fixation First Fixation Fixations

Total Duration

of Fixation

Duration of First Fixation

Number of Fixations

GrotipA t

p

Group B t

p

6.75 6.&1 3.31 8.16 -4.4 -4.55

.005 .005 .005 .005 .005 .005

5.64 5.69

.005 .005

.l4 .5S

.OtS .OS’S

-3.8 -f.96 .005 .005

-O.Q7 0.59

ILL 11.5.

-0.53 0.11

OS. 71.8.

-0.66 -0.S8

fl.s. fl.5.

Italics =satnples adjusted to control for age differences.

na. =not significant.

attempt was made to develop a test which

would be easily applicable in a clinical set-ting.

MATERIAL AND METHODS

Three groups of children aged 5 to 14

years were tested. Group A consisted of 25

children who had been admitted to the

hos-pital for a variety of reasons but were not

known to suffer from neurological or

emo-tional disease. Group B consisted of 25

chil-dren in whom a clinical diagnosis of

mini-mal cerebral dysfunction, as defined by

Clements,#{176} had been reached. Group C

con-sisted of 16 children who suffered from a

variety of other neurological and develop-mental disorders (e.g., mental retardation,

epilepsy, aphasia, and head injury). The

age ranges and sex distributions in these

groups are shown in Tables I and II,

re-spectively.

The experiment took place in a quiet,

electroencephalogram (EEG) recording

room. The subject was asked to look at a

primary stimulus (a red square with sides

measuring 3.8 cm situated at a distance of

approximately 168 cm). A secondary

stimu-lus, a small bright light situated approxi-mately 70#{176}to the right of his visual axis was then provided. This light could be con-trolled

by

the observer, who was also

oper-ating the electroencephalograph which

it-self was situated outside the room. There

was some diffuse light entering the room

from outside so that the primary stimulus

was plainly visible, even without the light provided by the secondary stimulus. In this

environment, however, other visual and

au-ditory distractions were reduced to a mini-mum.

The technique used was that of electro-oculography, modified from that described by Mowrer, et al.10 in 1936. This involves

recording the potential changes which are

brought about by an alteration in the

posi-tion of the comeal-foveal axis relative to

electrodes which are placed near the eye.

TABLE IV

t TEST FOR MEAN VALUER OF NORMAL CHILDREN

(GRoUP A) COMPARED TO THOSE OF Two STATISTICAL

SUBGROUPS (GROUPS B! AND B2) OF CHILDREN WITH

MINIMAL CEREBRAL DYSFUNCTION:

SEX RATIOS CONSTA NT5

df 35 A versux B1 A versus 112

Number of children 21 14 2! 14

Average total duration of fixation

5.35

p .005

6.82

p .005

Averagefirst fixation time

1.99 p .05

2.67 p .025

Average number number of fixations

-3.1

p .005

-4.96

p .005

* Since the t tests involved in this table are not

independent, a special table to obtain the significance

(6)

10.

8-

6-4.

2-GROUP

B

Mm. Cer. Dys.

GROUP

C

Other Neur. Prob.

4 8 12 16 20 24

‘I)

I-U

LU

-U

I,)

0

a

z

10-

8-

6-

4-2.

NO. OF FIXATIONS (including first fixation)

GROUP

A

Normal

FIG. 4. Diagram showing number of discrete fixations in normal (unshaded columns) and abnormal

(shaded columns) children. Note the tendency to a smaller number of discrete fixations in normal chil-dren. (Group A, 25 cases; Group B, 24 cases; Group C, 16 cases.)

(The potential difference along the

cor-neal-foveal axis itself is due to the complex

biochemical changes taking place in the

retina which create a negative charge; the

cornea remains positive.) Four silver-sur-faced electrodes 3 in. (6 mm) in diameter, coated with silver chloride, were placed

re-spectively at the glabella, at each outer

canthus, and, as a ground electrode, on the

forehead. Grasst electrode paste type EC2

was used to improve conduction and the

electrodes were fixed by means of transpar-ent adhesive tape4

The electrodes were then connected to

an electroencephalograph (Offner type T)

with AC circuit, permitting bipolar

record-ing on three channels, namely, between

each outer canthus and the glabella, and

between both outer canthi. Calibration was

at 5 mm pen deflection for each 50 tv of

potential change. Paper speed was 3 cm per

second. A time constant of 0.3 second was

used.

The subject was instructed to look at the

primary stimulus, and then a control

trac-f Grass Instrument Company, Quincy,

Massa-chusetts 02169.

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ARTICLES

u.s. = not significant.

ing

(

Fig. 1

)

was usually taken. During the tracing the subject glanced in the four

di-rections, up, down, and to either side.

Fol-lowing this the experimental period proper

was started. The child was instructed to

keep looking at the primary stimulus and

the secondary stimulus, of which he had

been warned, was provided. No further

in-structions were given. The experiment

lasted for 120 seconds. Following this the

trace was examined (Fig. 2) and the

fol-lowing measurements were recorded: (1)

total duration of fixation, i.e., the time

dur-ing which the eyes were fixed on the

pri-mary stimulus; (2) duration of first fixation

before the child looked away from the

pri-mary stimulus; and (3) the number of

dis-crete fixations.

RESULTS

The average results are recorded in

Table I, which shows the contrast between the “normal” Group A, the minimal cerebral

dysfunction Group B, and the other

neuro-logically abnormal Group C. The average

total fixation time of 112.9 seconds in

Group A is considerably longer than the

values of 72.7 seconds and 75.2 seconds for Groups B and C, respectively. The standard deviation of 7.2 seconds in Group A is also

much smaller than the value of 27.6

sec-onds in Group B and 31.6 seconds in Group

C. Figure 3 shows that, in spite of the last

two values, there is little overlap between normal and abnormal groups, and certainly the normal range is well defined. Because,

as will be shown, age is an important factor in this experiment, at least in the normal group. for statistical ptrpoc adj tistnients

were made in the numbers of the three

groups to make them comparable in this

re-spect

(

Table I ). Either with or without

these adjustments, the differences between

Groups A and B and between Groups A

and C are statistically significant at the .005 level

(

Table III).

The average duration of the first fixation

is also very different in Groups B and C as

opposed to Group A, and the differences

between Groups B and C on the one hand

and Group A on the other are also highly

significant (Table III). However, the range in all these groups is very great, so that the

individual measurement is difficult to

in-terpret in clinical terms (Table I).

The average total number of fixations is

also markedly different in the abnormal

groups as opposed to the normal (Fig. 4),

although in this instance too the range

shows a degree of overlap which makes

dis-tinction in the individual case impractical, though these differences are also statisti-cally significant (Tables I and III).

Maturation of neurological functioning is said to be slower in maleshl and this is

re-flected in Table II where it is shown that

they are relatively poor performers in the

normal group. Although on statistical analy-sis the sex difference is not significant, none

of the differences favor the males. This

difference does not hold, however, for the

two abnormal groups. Probably larger

num-TABLE V

EFFEC’I OF AGE (GRoUe A)

4

ge

Total Duration of

Fixation

Duration of First

Fixation

Number of Discrete

Fixation

6-7 yr colnpared to 8-9 yr

6-7 yr compared to over

lOyr

8-9 yr compared to over

lOyr Regressionanalysis

t= 1 .66 p .05

t=2.27p .005

t=1.61p .10

f=7.35p .01

t= -1 .23 I1.S.

t=3.13p .025

t=1.57n.s.

f=8.47p .01

t= .70 fl.S.

t=3.78p .005

(8)

hers are required before the effect of matu-ration factors can he fully assessed. Because

of the large proportion of males in Group B,

two subgroups were developed in which

the ratios between the two sexes were corn-parable (Table IV) . The statistical analysis

of these two subgroups, compared to Group

A, showed no significant differences from

the results obtained without such

propor-tionalization (Table III).

Another factor which influences each of

the three values is age. There is a tendency

for the values to change with increasing

age, in the direction of increasing ability to attend to the task. This is shown in Figure

3. Further, if Group A is divided into

subgroups according to age (children aged

6 to 7 years, those aged 8 to 9 years and

those aged over 10 years), the difference

between the means of total duration of

fixa-tion of 108.7 seconds for the youngest

group and 119.8 seconds for the oldest

group is significant at the .005 level; and, although the difference between the middle

(mean 114.2 seconds) and the oldest

groups is not significant, a trend is

sug-gested (Table V). Some age differences in

respect to the duration of first fixation and

number of discrete fixations are likewise

significant.

DISCUSSION

These results show that the method is a

valid one for the objective demonstration of

differences between children without

neu-rological disease and those in whom a clini-cal diagnosis of minimal cerebral

dysfunc-tion has been made. However, it does not

demonstrate a difference between children

with minimal and those with grosser forms

of brain dysfunction (as represented by

Group C). Subjects in whom a diagnosis of

minimal cerebral dysfunction had been

made had all been assessed by a pediatric

neurologist and frequently also by a

psy-chologist, child psychiatrist, and

educa-tional psychologist. Although the duration of first fixation and the total number of

fixa-tions have too wide a range of normal

values to be conclusive, the total duration

of fixation in normal children is defined

‘e11 enough that it can be used as a

diag-nostic aid.

It is difficult to be certain, however, what

factors are being measured. As Stevens, et

al.1 pointed out, although their methods

were mainly concerned with disorders of

attention

(

attentional impersistence, or lack of attentional focus

),

they did not measure

“pure” factors, and the same holds true in

the present instance. Other factors such as

oculomotor hyperkinesis, impulsiveness and

distractability may play a part which

can-not yet be clearly outlined. Both

neuro-physiological and psychological studies

have demonstrated the complexity of the

whole question of attentiveness.

Neurophysiological studies show that

at-tention, consciousness, sleep, and wakeful-ness depend on the ascending reticular

acti-vating system of the brain stem and upon

the diffuse thalarnocortical projection

system.12 In animal studies, the amygdala,13

the inferior thalamic peduncle,1 and a

number of cortical areas such as the medial frontal cortex, the presylvian sulcus, the

lat-eral surface of the frontal lobe, the

tem-poro-occipital cortex, and certain diffuse areas of the parietal lobel5 have also been

shown to be involved. Depth electrode

re-cordings in humans have implicated similar areas.1#{176}In cats, responses have been found to depend on the past experience of the an-imal and on its state of alertness.17

In normal humans, investigations of

at-tentiveness by means of the EEG recording

or by sensory evoked potentials have

shown, in experiments lasting over a period

of one hour, a complex train of events

in-volving several steps, the final one of which

is sensory conditioning.18 The amplitude of

evoked potentials, investigated over a

simi-lar period, has been shown under certain

circumstances to serve as a measure of

vigilance.b9b0

Other neurophysiological phenomena

which have been shown to vary with the

(9)

ARTICLES

Psychological studies of attention

phe-nornena are numerous but are mainly

con-fined to adults.23,24 Trehub, et al.25 have

used an apparatus similar to the present

one for psychological studies. Among

chil-dren with cerebral palsy, Logue2#{176} found

more distractability when there was a

cer-tam amount of light in the room than when

it was completely dark, but Browning8

found that visual distractability as a

behav-ioral correlate of brain damage remained

an open question.

IMPLICATIONS

However complex these processes are,

the method described here for measuring

them has the advantage of being simple to

apply in a clinical setting. Although it is not clear precisely what is being measured, the

values obtained seem to be related to (1) a

maturational process and (2) the presence

or absence of clinical and laboratory

fea-tures of brain dysfunction. It is important

to determine whether they are also related

to behavioral disorders not usually

asso-ciated with brain dysfunction, whether they are related to mild degrees of mental

retar-dation, and whether they might prove a

valid measure of the effect of drugs or other forms of therapy.

SUMMARY

1. A method, using the technique of

elec-trooculography for measuring various

fac-tors related to attention is described. This technique is readily applicable in the clini-cal setting.

2. Three measurements were obtained:

(a) the total length of time during which visual fixation on a target was maintained

in a period of 120 seconds; (b) the

dura-tion of the first fixation; and (c) the total number of fixations in that period.

3. The first of these measurements

distin-guished normal children (who were able to

fix the target for longer periods) from those

with brain dysfunction. The second and

third are too variable to be of use in an

in-dividual case, though the mean values in

groups of subjects without neurological

dis-ease differ significantly from those with

minimal cerebral dysfunction and more

gross forms of neurological disease. Normal children tend to fix the target for a longer

period before looking away for the first

time, and they tend to look away from and

return to the target less frequently than

neurologically abnormal children.

4. All the measurements bear a

relation-ship to age, in accordance with the

pected maturation of ability to pay atten-tion, in the normal child. The total fixation time is again the most reliable measure.

5. In addition to its potential value as a diagnostic aid, future possible uses of the

technique include the assessment of

im-provement in children with cerebral

dys-function under various forms of treatment.

REFERENCES

1. Stevens, D. A., Boydstun, J. A., Dykman,

R. A., Peters,

J.

E., and Sinton, D. W.:

Pre-sumed minimal brain dysfunction in

chil-dren. Relationship to performance on

se-lected behavioral tests. Arch. Gen. Psychiat., 16:281, 1967.

2. Ounsted, C.: The hyperkinetic syndrome in

epileptic children. Lancet, 2:303, 1955.

3. Hutt, C., Hutt, S.

J.,

and Ounsted, C.: The

be-haviour of children with and without upper

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4. Foshee,

J.

G.: Studies in activity level: 1.

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Ment. Defic.,

63:1034, 1959.

6. Schulman, J. L., and Reisman, J. M.: An

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hyperkinetic behavior: II. Laboratory and

clinical evaluations of drug treatments.

Neu-rology, 17:467, 1967.

8. Browning, R. M.: Effect of irrelevant

periph-eral visual stimuli on discrimination learning

in minimally brain damaged children. J.

Consult. Psychol., 31:371, 1967.

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children. N.I.N.D.B. Monograph No. 3.

Washington, D.C.: U.S. Department of

Health, Education and Welfare, 1966.

10. Mowrer, 0. H., Ruch, T. C., and Miller,

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eye movements. Amer.

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Physiol., 114:423, 1936.

11. Bentzen, F.: Sex ratios in learning and

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12. Lindsley, D. B.: Attention consciousness, sleep

and wakefulness. In Field

J.,

Magoun,

H. W., and Hall, V. E., ed.: Handbook of

Physiology, Vol. III, Section 1. Washington,

D.C.: American Physiological Society, p.

1553, 1960.

13. Kaada, B. R., and Johannesen, N. B.:

General-ised electrocortical activation by cortical

stimulation in the cat. Electroenceph. Clin.

Neurophysiol., 12:567, 1960.

14. Skinner, J. E., and Lindsley, D. B.: The effect of cryogenic blocking of the diffuse

thalamo-cortical recruiting system upon visual

evoked potentials and behavior. Electroen-ceph. Clin. Neurophysiol., 23:79, 1967.

15. Fangel, C., and Kaada, B. R.: Behaviour

“at-tention” and fear induced by cortical

stimu-lation in the cat. Electroenceph. Clin.

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16. Cuerrero-Figueroa, R., and Heath, R. G.:

Evoked responses and changes during

atten-tive factors in man. Arch. Neurol., 10:74,

1964.

17. Jane, J. A., Smirnov, C. D., and Jasper, H. H.:

Effects of distraction upon simultaneous

au-ditory and visual evoked potentials.

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18. Garcia-Austt, E., Bogacz, J., and Vanzulli, A.: Effects of attention and inattention upon

vi-sual evoked responses. Electroenceph. Clin.

Neurophysiol., 17:136, 1964.

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Selective attentiveness and cortical evoked

responses to visual and auditory stimuli.

Sci-ence, 148:395, 1965.

20. Haider, M., Spong, P., and Lindsley, D. B.:

Attention vigilance and cortical evoked

po-tentials in humans. Science, 145:180, 1964.

21. Low, M. D., Coats, A. C., Rettig, C. M., and

McSherry, J. W.: Anxiety,

attentiveness-alertness: a phenomenological study of the

C.N.V. Neuropsychologia, 5:379, 1967.

22. Caarder, K.: Fine eye movements during

inat-tention. Nature, 209:83, 1966.

23. Gardner, R. W., Jackson, W., and Messick,

S. J.: Personality organisation in cognitive

controls and intellectual abilities. Psychol.

Issues 2, Monograph 8, p. 27, 1960.

24. Bloomberg, M.: Field independence-depen.

dence and susceptibility to distraction.

Per-cept. Motor Skills, 20:805, 1965.

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Appa-ratus for measuring interest patterns by

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Acknowledgment

We are indebted to Dr. H. C. Dunn, Dr. S.

Drance, and Dr. Morton Low for criticism and

ad-vice, and to Mr. R. D. Ferguson for technical

ad-vice and assistance. Mr. D. Crockett performed the

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1969;44;365

Pediatrics

John U. Crichton and Harley P. Mackoff

DYSFUNCTION

A CLINICAL APPROACH TO THE MEASUREMENT OF CEREBRAL

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1969;44;365

Pediatrics

John U. Crichton and Harley P. Mackoff

DYSFUNCTION

A CLINICAL APPROACH TO THE MEASUREMENT OF CEREBRAL

http://pediatrics.aappublications.org/content/44/3/365

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References

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