Epson L90P - TM Two-color Thermal Line Printer Manual de usuario descargar pdf (Pagina 48)

DID YOU KNOW

that, when you

are

dizzy or

when

you

are dreaming,

your

eyes "beat" involuntarily? (They

rotate

slowly in one

direction and reverse

quickly,

repeating the

cycle

rapidly

and

frequently.)

Well,

they

do. It's

a perfect-

ly

normal

condition called nystagmus

and medical

electronics technicians have

now

developed

an

instrument

that re-

cords nystagmus

for analytical purposes.

The machine

is called

( wouldn't

you

know

?) an

electronystagmograph

or

ENG.

To

use the ENG,

electrodes

are taped

to the

patient's head near

the eyes

and

the eye movements

are sensed,

amplified

and recorded

on strip

chart

paper.

The

instrument

is

all solid -state

and the re-

corder

uses

heat

-sensitive paper

with

a

hot

stylus. The ENG

can detect even

low-

intensity

nystagmus that might

eas-

ily escape

visual observation.

What's It For?

Actually,

the ENG is

being used more

by

otologists

(ear spe-

cialists) than by ophthalmologists

(eye

specialists). This is

because

dizziness

is

associated with the balance system,

which

is

located in the inner

ear.

The

otologist

is

interested in irregular patterns

of nys-

tagmus, spontaneous nystagmus,

or its

absence to give him an indication

of the

condition

of the ear.

In the clinic, it is

often necessary

to

induce

dizziness in order

to record

the

nystagmus.

This

can be done

by securing

the patient in a motor-

driven chair

that

spins

around -not

a

very

comfortable

ride

for most

people. It is more

common,

therefore,

to use a method

called the

Fitzgerald

-Hallpike technique of caloric

irrigation.

In this method,

the patient's

ear is irrigated

with warm or

cool

water.

The

temperature

change upsets

the in-

ner

ear and makes him

tipsy.

Who

Uses

It?

The ENG

is also

used

as a

general eye- movement monitor.

By

re-

cording

eye movements

during reading,

it

is helpful

to the teacher of speed -read-

ing

courses and

to

the

speech patholo-

gist in providing

therapy

for

children

with stuttering problems.

Psychologists

use the ENG

to

deter-

mine

whether

or not a subject

is dream-

ing in ESP research.

One subject

tries

to

transmit

a

thought

pattern to a sleeping

subject who has

the

ENG electrodes

at-

tached.

If

the

latter

starts to

dream,

which

he's not supposed

to do

if

ESP is

to work,

nystagmus

will

show

up on

the

ENG and he can be awakened.

Next

time you

feel

a

little

dizzy, make

an

appointment

with

the nearest

elec-

tronystagmograph

if you're not

too far

gone

to

say

the word. 30

The electronystagmograph is

used

in clinic

or

hospital

to

diagnose

and

record various

malfunctions

or

dis-

eases

of the ear or

eye. Movements

of the eyes

are recorded for reference.

(Photo by Tracor, Austin,

Tex.)

52

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