Unreal assessment of space and disturbed reflex time in workers exposed to the effect of organic solvents benzene derivatives

179

of Occupational Accidents, 4 (1982) 1'79-185 Elsevier Scientific Publishing Company,Amsterdam-Printed inThe Netherlands

Journal

UNREAL

ASSESSMENT

OF

SPACE

AND DISTURBED REFLEX TIME IN WORKERS EXPOSED

TO THE EFFECT OF ORGANIC SOLVENTS,BENZENE DERIVATIVES Jivka Petrova Vasileva Medical Academy, Institute of Hygiene and Occupational Health Boul. D. Nestorov 15, Sofia 1431, Bulgaria

ABSTRACT Studies have been performed on 50 workers exposed to organic solvents (benzene derivatives) at concentrations surpassing MAC several times and a control group of 30 workers having no contact with the above mentioned solvents. A new method has been used to study the effect of the caloric provocation of the vestibular system on the perception of time and intensity and localization in space by the auditory organs of sound. It was found that caloric provocation of vestibular organ caused more frequent disturbances in the perception of time, intensity and localization of sound in the auditory organ among the solvent-exposed workers than among the controls. The unreal assessment of time and disturbed sound localization in space leads to inadequate solutions of conflicts and to ill-timed reactions, INTRODUCTION

Toxic

substances above threshold concentrations disturb the fine

perceptive mechanisms of specialized sensitivity, in particular auditory and vestibular analyzers, and create real conditions for misinformation of the reflection obtained by them about the objective world. The vestibular system in man is disturbed by industrial_ solvents (Larsby et al., 1976; Aschan et al., 1977: Odkvist et al,,

1979).

The effect of organic solvents on the vestibular analyzer has thus become a subject of intense interest in occupational medicine. Rechtain (1979) reported vestibular malfunction as one of the main early symptoms following organic solvents poisoning. some studies on workers in the shoe industry qave grounds for concluding that the al.terations caused by organic solvents could be classified under the "Toxic nucleovestibular syndrome", describinq lesions of the nerve structure in the bulb. 0376-6849i82/0000-0000/$02.75 0 1982 Elsevier Scientific

Publishing

Company

180 The effect

of the vestibular

investigated

by Bazarov

provocation

changes

localization organ

(Kehaiov,

The purpose occurring workers

auditory

of sound

of the present

study

organic

xylene),complaining

of individuals

comprised

of 50 workers

ranged

over

in the same production

3 years

2. A control above-mentioned

the changes

derivatives

of

symptoms.

specially

arc with

lator,

a registering

is carried of a stand, where

with

no contact

of

with

the

included

the

to the electronic

imnulses:

stimulator

which

and

by

have

mechanical

a

stimu-

and releasing

stimuli

of a special

arc and fixed is fixed

sound

to the electronic

by pressing

of the sound

5" could

produced

connected

operated

out by means

the arc

b through

is carried

on a chair against are then

with

already

device

for the arc and the loudspeaker. is a scale

be read;

frequency

horizontal

plane

of the labyrinths

out as follows

his head

the special switched

parameters

300 ms; duration

occurred

The age

of service

where

the arc

the angle

itself

of the

is also

- "An.

study

initial

a length

(benzene

times.

for this purpose

connected

in direction

been given

resting

with

which

loudspeaker

device

consisting

turning

constructed

the subject

The change

graduated

solvents

MAC by to 8-10

workers

stimulator,

mounted

which

In the place

organic

investigation.

sector.

of 30 healthy

an electronic

a switch,

with

exceeding

of this

solvents.

mobile

sound

and

vestibular

i.e. benzene

the material

from 25 to 45 years

group

equipment

following:

meters

intensity

provocation

of different

in contact

of the group

sits

sound

an injured

the vestibular

solvents,

at concentrations

The

was

AND METHODS

1. A group

arc

with

was to investigate

during

derivatives)

hand.

of time,

in patients

perception

with

toluene,

Two groups

The

threshold

that vestibular

1977).

in contact

MATERIAL

on the sound

It has been established

perception

in space

in auditory

(benzene,

stimulation

(1968).

were

back

period

impulse

the patient

at an anqle

localization

then performed was asked

electronic

sound

of the sound A caloric

and when

to give

the subject of 30', the head

The chosen

of the sound

20 ms;

and 5' on the vertical. was

1974):

of the device.

into the different as follows:

of the sound 3.5 KHz;

leaning

support

(Kehaiov,

devices.

The

repetition

intensity source

65 dB(A);

0' on the

prOVOCati0I-I

the veetibular

an account

para-

Of One reaction

of the changes

which

181 the vestibular

provocation

also provoked.

The angles

Later

had caused. involved

could

on the other

be calulated

SIN6 SINY

=

SIN@

COSfi

=

SINr*

SINP

cos

Fig.

1. Calculation

of sound

labvrinth

is

(Fiq. 1).

5

localization.

RESULTS

The

results

method

have

of Student-Ficher

the examinations

group

to statistical

a probability

out on the group concerning

analysis

of p < 0.01. exposed

using

The results

to organic

the perception

the of

solvents

of time are given

in

1.

Vestibular ception

provocation

of sound

intensity

was

8 cases

found

group,

for the left

group

to produce

in sound

intensity

and

intensity

in the per-

increasing

for the left

sound

labyrinth

a change

group,

sound

labyrinth

was

in 6.6 % of the cases

and

registered

in 6 % for the right

increased

and 6.6 % for the right

occurred

% for right

Deviation exposed

Decreasing

the sound

labyrinth

intensity

and 13.33

found

In the exposed

in 20 % of the cases one.

(16 8) for the left

the control

deviation

was

intensity.

30 % for the right

sound

subjected with

carried

and on the control Table

been

in

one.

Tn

in 10 8 of the cases

one;

a reduction

for the left

in

labyrinth

one. localization

was as follows:

in 36 % of the cases

with

during

vestibular

provocation

examined

provocation

in the

of the left labvrinth

occurred

to the left

(24 %) and

1.

(in ms)

1

0.001

P

group

2

control

group

25.00

40.00

15.63

0.001 94.11

0.001

10.0

16.32

300.0

325.0 13.89

500.0

26.02

340.0

405.71

394.11

60.0

300.0

300.0

60.0

48.0

36.0

13.33

13.33

34.0

in the of time

42.0

105.71

-

No changes perception

left right labyrinth

of time

left right labyrinth

Perception delay

48.89

0.01

4.95

28.47

284.37

251.11

26.26

18.0

exposed

13.13

51.91

6.78

sx2

or

18.54

sxl

delay

286.87

x2

26.26

22.0

249.09

2

1

of time

left right labyrinth

Perception speed up

x1

period

of examined

speed up of the rhythm

Average

Repetition

persons

Percentage

Table

183 (6 %). With

to the right ation

was

the right. occurred

Sound

localization

in 6 % in left

labyrinth

vestibular

vestibular

in Table

in front

labyrinth

18.66

of the examined

23.33

%. The values

subjects

group

during

% and during for angular

labyr-

the left

the right deviation

are

2.

Table 2. The average values for the angles of sound vestibular provocation in the exposed group.

The horizontal

angle

(V)

angle

localization

during

Left labyrinth left right localization

Right labyrinth left right localization

25.34

25.03

28.48

17.71

12.29

9.36

16.34

7.45

X1 SXl

The vertical

the devi-

and 10 8 in right

for the control was

labyrinth

- 34 % to the left and 6 % to

provocation

provocation

provocation

of the right

examined

The deviation

inth provocation.

given

provocation

in 50 8 of the cases

(S)

x1

31.16

sxl

15.89

11.6 2.03

25.42

27.12

15.06

17.22

DISCUSSION It has been

established

show a deviation cation, delay time

with

a tendency

in time during lost have

that more

in the perception

been

The perception

towards

provocation greater

of delay

than

process,

the functions

of the gravitation

same to a considerable vestibular

apparatus

reiteration

in space

and the examinee, regard

T = T'

rate

we

1

labyrinth.

for the speed

up of time

mechanisms

should

psycho-

mechanisms.

Changing we put the

By provoking

two persons

the

of sound

- the examiner,

physical

is in a non-inertia be accordingly:

of

up in time.

in the period

to two different

for a

The values

of the organism state.

for changes

the examiner

workers

provo-

is a higher

by many different

in fact examined

as they belong

of the examiner

1 - v2/c2

those

vestibular

of time and especially

of the left

in non-inertia

and looking

to the examinee

time duration

realized

50 % of the exposed

a speed-up

and speed

physiological

than

of time after

states.

state

With

and the

184 where

T is the time duration

the examined C velocity

person,

of light.

(the examiner) moves

more

(according

we accept

to explain

tude

to detect known

cells

situated

In order of the

are thousands

with

in otoneurological

The vestibular much more organic

solvents.

during

Tt is obvious

group

with

tal angle

?n contrast

Connecting

the level

ation

vestihular normal nucleus

over

analyzer

conduction

found

intensity with

especially

changes

in the

in the exposed

to the left

also

in the horizon-

(S-1. in the localization

in a third

part,

at these

cortex)

system

direction,

i.e.

the system across

intensity

analyzer

stem and polysensory

it should and changes

and

and particularly

we can suppose

then

levels.

sound

to the vestibular

brain

the organism,

all over

of time,

the auditory

of the impulses

and pathway

mainly

an alteration

connected

of the cerebral

is applied

was

in space with

of the peripheral

areas

of of

in the same group.

has caused

direction

group,

sound

in contact

was perceived

in space

in perception

the part of the system

grating

for the perception

person.

the changes

its localization with

of time

non-inertia

in the perception

or reduced

labyrinth

of the source

group

the opposite

had been

provocation

of sound

to the control

in the exposed

(for example

i.e. the speed-up

accept

intensity

in vertical

of the examined

of correspondina

the change

side

that vestibular

in front

and millions

which

sound

of the right

of sound

It is

organ

has amplified

a dislocalization

unless

of maqni-

in this way.

in the group

(L') and also

orders

acceleration.

in the mechanism

patients

of localization

a

in our cases

of the formula,

by several

tendency,

explained

Increased

provocation

perception

changes

provocation

frequently

applied

shows

in a sensory

we should

(1977, 1978)

person

stem and cortex.

the opposite

person,

connected

and Einstein).

by means

cell

person

are prolonqed

the provoked

of an "insignificant"

in the cerebral

to explain

Kehajov

where

the acceleration

receptor

there

investigated

tendency time. time

the effect

one)

Fitzgerald

of

oerson, observer

of the examined

of fluctuations

on amplification

that for one

the auditory

system

such phenomena

the hypothesis

well

that

of the examined

in view of the motionless

only cases

in time. We consider

is too small

that

of Lorenz,

this concerns

T' the time duration

of movement

in the motor

as the periods

to concepts

However, delay

This means

everything

slowly,

of the examiner,

V the velocity

that

if acceler-

be reflected would

the synapses

(at

inte-

occur

of each

by the in the

branch,

185 The narcotic suppression degrees

effect

is observed

provocation

nervous

before

organ

disturbances

and sound

solvents

system.

suppression.

test of vestibular

of solvent-induced intensity

of the organic

of the central

is connected

Stimulation

This work

with

shows

how caloric

can be used as an early

in the perception

the

of varying

of time,

detection

sound

localization.

CONCLUSIONS

In conditions solvents thus may

suggesting lead

involving

various

forms

for changed

to disturbed

and working

functions

Thus

erroneous

in production

operations

and conflict

production

processes

sound

signals;

break-down

reactions

(delay or speed

Incorrect

localization

opportunity

to erroneous

of the vestibular

of auditorv

work

in which

signals).

situations

are guided Untimely

functions

apparatus.

(assembly

by means reflexes

signal

This

in the work

may be expected

eg.

line type

of periodic and behavioural

may be expected

of guidance

to organic

complaints,

information

decisions

up of a stop)

in space

exposure

are some of the first

transmission

environment.

long-lasting

systematic,

of vertigo

as a result.

sounds

gives

an

of the worker.

REFERENCES

Andrea, D., Cawazzini, M., Perbellini, L., Apostolie, P. and Zampieri, P 1979. Alterazioni vestibularien operai calzuturieri. Med. Laboro, 1: 16-20. Aschan, G., Bunufors, I., Hydan, D., Larsby, B., 'i)dkvist, L. and Tham, B 1977. Xylene exposure. Electronystagmographic and gaschromatog;Aphic studies in rabbits. Acta otolaryngol. (Stockholm), 84: 370-376. Bazarov, V.G., 1968. The influence of vestibular stimuli on the auditory sensitivity. Vest. ORL., 6: 17-21 (in Russian). Kehaiov, A.N., 1977. Vestibular effect on the auditory function. Min. Otorinolaryngol., 27: 165-170. Kehaiov, A.N., 1978. Space, time, movement (vestibular, visual and auditory function). Med. i fiskult., Sofia. Larsby, O., ijdkvist, L., Hyden, D. and Liedren, S., 1976. Disturbances of the vestibular system by toxic agents. Acta Physiol. Stand., 440: 108-112. Bdkvist, L., Larsby, B., Tham, R. and Aschan, G., 1979. On the mechanism of vestibular disturbances caused by industrial solvents. Adv. Oto-Rhino-Laryng., 25: 167-172. Reshtein, N.N., 1978. A study of the function of the vestibular analyzer in workers of paint and varnish manufacture. Vest. OLR., 3: 22-26 (in Russian).