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Regional Issues in
Neurobehavioral Testing:
An Overview
Ann M. Williamson
It is clear in reviewing the other three chapters in this section on
"regional issues" that there are great differences in the status and
application of neurobehavioral testing among regions. Of the regions
represented, most activity is occurring in Europe, mainly in research
on the neurobehavioral effects of particular toxic substances and in
the development of tests that can be used across regions. Comnara-
. ~ .
. . . - · . · · · .. . . . . . A- At,
tinkly less activity Is occurring In the less developed regions of (China
and India. The activity that is occurring there is directed at researching
neurotoxicological problems that are common in each particular region.
For example, in India, which has a predominantly agricultural base,
a considerable proportion of research has been on the effects of pesticides
and larvicides. Virtually no research has been directed at developing
tests that are specifically designed for the local population. All tests
used in studies in both regions were developed in Europe, Scandinavia,
or the United States.
This difference in degree and focus of activity is largely due to the
comparative age of the area as a field of inquiry in each region. The
chapters by Liang and Saxena demonstrate that, despite the lack of
activity in test development in their regions, there is an obvious awareness
of the issues involved. The arguments put forward in both chapters
highlight regional differences as important factors to be considered
in the development of new tests and test batteries.
337
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338
ANN M. WILLIAMSON
EFFECTS OF REGIONAL DIFFERENCES
There are a number of primary issues that must be considered in a
discussion of the effect of regional differences on test design and development.
Exposure Characteristics of the Region
The main types of neurotoxic hazards are likely to differ from
region to region. Carbon disulfide, for example, one of the earliest
occupational neurotoxins to be studied by neurobehavioral methods
(Hanninen, 1971), is used widely in Europe and the United States but
is used to a much smaller extent in Australia. Consequently, the
need to develop tests for this particular hazard in Australia is limited
and will be overshadowed by more commonly encountered hazards
such as lead, organic solvents, and organophosphorus pesticides.
Similarly, the need to study the neurobehavioral effects of abalone
diving (Williamson, et al., 1987), although not a common occupational
problem in Australia, would not even occur in many other countries
because professional diving is uncommon for practical or commercial
reasons.
Regions also differ in the degree of exposure to particular neurotoxins.
In developing countries where occupational hygiene standards have
not reached the same levels achieved in some of the developed countries,
poisonings are not uncommon. Thus, the perceived need for
neurobehavioral testing is less because frank clinical symptoms provide
clear evidence that the substance is neurotoxic.
Combinations of hazards are also likely to be unique to particular
regions. The effects of thermal stress, for example, may well interact
with the neurotoxic action of a substance and, as a result, confound
the measurement of neurotoxic effect. The extent of the interaction,
of course, depends on the degree of thermal stress, but in regions
such as the tropics where extreme temperatures are common,
neurobehavioral test development must take this into account.
Ethnic Composition of the Region
Regions differ in the relative homogeneity of ethnic backgrounds
and languages. Saxena pointed out the difficulties of testing in situ-
ations such as in India, where there are many different language
groups, and called for the development of culture-free tests that could
be used to compare results across the country.
The need for culture-free tests becomes even more important in
regions such as Australia where it is not uncommon to have 20 or
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REGIONAL ISSUES IN NEUROBEHAVIORAL TESTING
339
more language groups in a single work force of a few hundred. Test-
ing can become very difficult in ethnically heterogeneous regions
due to the problems of ensuring (1) that test instructions are compre-
hended by workers of each language group and (2), where different
forms of the tests must be used for different groups, that they are in
fact identical. The difficulty experienced in attempting to adapt measures
of mood for different language groups, discussed by Gilioli and Cassitto,
where there may be no direct equivalents in the new language to
certain words used in the original version is a perfect example of the
latter point. Even where the same words exist across language groups
it is quite likely that the meanings are different.
The problem of language differences across cultures is clearly im-
portant because one of the primary aims of the World Health Organization
(WHO) Neurobehavioral Core Test Battery initiative is to obtain cross-
cultural baseline measures on a group of tests. If this can be achieved,
we will have a set of tests that can be applied in many countries. The
development of tests that have multiple language equivalents should
be extended however and, where possible, the language problem should
be avoided by the use of performance tests that are not language
based. The exception to this, of course, is where testing for verbal
abilities is the main object of a test.
Educational and Socioeconomic Characteristics
The educational and socioeconomic characteristics of workers dif-
fer among regions. This factor presents a number of problems. The
degree of illiteracy differs between regions such that it is relatively
uncommon in the developed countries but still common in the developing
countries. Illiteracy presents much the same problem for testing as
does language difference except that nonlanguage-based tests are essential
not just advantageous. In both cases there is the additional problem
of the approach to neurobehavioral testing of workers who are not
only unused to being tested but may also not understand properly
why they are being tested or what they are being asked to do.
The worker's approach to testing and the test situation has become
increasingly important with the greater use of computer-assisted testing.
In this case, both literacy and computer literacy need to be taken into
account because unfamiliarity with computers is likely to have the
same effect on testing as illiteracy does. Socioeconomic status is also
an issue in this area because it is well established that many of the
factors associated with low socioeconomic status, in particular, inde-
pendently affect behavior (Cravioto and Delicardie,1973~. Malnutrition,
for example, has a marked effect on most aspects of human perfor-
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ANN M. WILLIAMSON
mance (Brozek, 1978) and would undoubtedly confound any attempts
to measure the neurobehavioral effects of a specific toxic substance.
Attitudes to Testing in the Region
Regional differences may also be evident in workers' attitudes to
tests and their motivation to participate in them. In areas where health
information is limited and mental illness is regarded with fear or
suspicion it may be difficult to convince many workers to participate
in a testing program. Where employers have little knowledge about
the potentially toxic effects of substances in their workplaces or take
little responsibility in informing workers by such means as workplace
training courses or material safety data sheets (MSDS), or where employees
have little awareness of their "right to know" about the degree of
safety of substances in the workplace, it is likely that reluctance to
participate in testing programs will be encountered. It is important,
therefore, that test batteries be developed for those conditions that
are acceptable both to the workers who are to be tested and to the
employers who will permit testing to be carried out in their workplaces.
Until mass education programs have widespread impact in these ar-
eas, it is important to take such factors into consideration when designing
test batteries or attempting to apply existing ones in new regions.
Test motivation, and in some cases even performance, will also be
influenced by the real or perceived implications of finding neurobehavioral
impairment. Where workers differ in political reactivity, motivation
to participate and to perform in toxicity testing will also differ. In
regions where job security is uncertain, workers may be unwilling to
participate or motivated to deny symptoms for fear of losing their
jobs. On the other hand, in regions where workers compensation systems
are liberal, there is a risk that workers may fake poor performance
and "malinger" in order to obtain the benefits of the compensation
system.
The latter problem, where it occurs, presents a significant impedi-
ment to accurate testing for neurobehavioral impairment, particularly
of individual workers. It is virtually impossible to unequivocally di-
agnose faking; however, the American Psychiatric Association's (1980)
DSM III lists a number of features- associated with faking that can
provide a guide. In addition, Lezak (1983) describes a number of
tests that can be added to a test battery where faking may be a problem,
which will provide an estimate of the degree of faking by a subject.
Any attempt to make international comparisons or to translate tests
or even test results between countries needs to take into account such
issues as those discussed above. Failure to acknowledge differences
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REGIONAL ISSUES IN NEUROBEHAVIORAL TESTING
341
between regions on exposure, ethnic, socioeconomic, and educational
dimensions, as well as in attitudes to neurobehavioral testing, will
certainly limit the quality and applicability to the local population of
the results of studies when they are performed in a new country or
region.
STATUS OF WORK IN THE RESEARCH AREA
The amount of activity in the area of neurobehavioral toxicity testing
in different countries is very variable and limited to distinct regions
of the world. Clearly a great deal of work is going on in Europe and
North America relative to the rest of the world. As a consequence it
is in these regions that the most impact has been made on Threshold
Limit Values (TLVs) and neurobehavioral test development has been
a high priority. On the face of it, the limiting factor to activity in this
area would appear to be whether the region is developed or not.
Certainly the chapters in this section describing the position of
neurobehavioral testing in China and India support this concept. It is
likely, though, that the extent of development in a region is not the
only factor governing the amount of activity in this field.
In Australia, for example, which would be classified as a devel-
oped country, there is relatively little activity in neurobehavioral toxicity
testing and, partly as a consequence, there has been little impact on
permissible health standards. In addition, until very recently, there
has been limited awareness by the working population about neuro-
toxicity as an occupational problem. Although this situation is changing,
it has been due largely to the action of political and industrial relations
forces that have traditionally focused on issues other than occupational
health. One major factor governing the degree of emphasis and
responsibility that governments win take on the issue of neurobehavioral
testing is, of course, how important it is considered to be relative to
other issues. In countries where basic public health is still an enormous
issue and where people are regarded as lucky to even have a job, it is
not surprising that neurotoxicity problems are regarded as a fairly
low priority until a major incident occurs such as in Bhopal. Other
health and safety factors have assumed precedence in some countries
where, even though most basic health problems have been brought
under control, neurotoxicity testing still lags behind other health and
occupational health issues. This, coupled with the general belief that
neurotoxicity testing is looking at comparatively subtle changes, results
in very low priorities being assigned to the area.
Nevertheless, attitudes to assessment of chemical hazards are changing
around the world and some neurotoxicity testing is being conducted
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ANN M. WILLIAMSON
using animal models for certain categories of chemicals (notably new
pesticides). Also, as animal welfare concerns increase, toxicology
evaluators are demanding more information from conventional toxicity
studies. One such source of information is the results of neurotoxicological
investigations where ongoing study of sensitive indicators may pro-
vide a unique and timely measure of potential hazard.
Education and Training
A higher profile can be achieved for neurotoxicity testing through
education of workers and the public. This, however, requires experts
who are themselves aware of the need for neurotoxicity testing and
the issues involved. It also requires financial resources to implement
large-scale education programs. In countries where, for whatever reason,
the area is largely overlooked, there are often very few experts to
take on this role and very few training opportunities to increase their
number. With few experts to lobby governments, the allocation of
financial resources to improve this situation is unlikely to occur.
This is clearly a circular problem and one whose solution probably
requires the exchange and promulgation of research findings and
information about activities in other countries. Opportunities for this
to occur have certainly increased in recent years. There have been a
number of international meetings of experts involved in neurobehavioral
toxicity testing since 1980, mostly conducted under the auspices of
the WHO. These have provided the conditions for invaluable discourse
between workers in the field and have had an obvious impact on the
quality of research being conducted. Unfortunately, most of these
meetings until now have been held in the Northern Hemisphere, thus
severely limiting the involvement of workers from the Southern
Hemisphere due to the costs of travel to the meetings. The cost of
attending meetings is also likely to be a limiting factor for scientists
from developing countries even in the Northern Hemisphere. In fact,
scientists from any country in which neurobehavioral toxicology is
not a priority are likely to encounter difficulties in obtaining any
kind of support, either financial or in time off from work, to attend
such meetings.
Apart from these scientific meetings the only other organized
mechanism for the exchange of neurotoxicity research findings and
test methods is through the scientific literature. Additional mechanisms
include the institution of visiting fellowships at some of the more
advanced research centers, as well as scholarships for postgraduate
and postdoctoral students. Specialized training courses such as that
conducted at the University of Milan under the sponsorship of the
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REGIONAL ISSUES IN NEUROBEHAVIORAL TESTING
343
WHO are a very efficient, if brief, mode of providing information on
at least some aspects of the subject. Training courses are an especially
important way of increasing exchange between workers in the field
because the information they provide can form the basis of training
programs in the trainee's home country. For this reason, more
comprehensive training courses should be encouraged in one or two
centers around the world.
Is the Concept of a Global Test Battery Feasible?
With the development of the WHO Neurobehavioral Core Test
Battery, the concept of a global test battery that could be used for
multiple toxins in virtually any country becomes more of a reality.
Obviously there are a number of problems such as those listed in the
beginning of this chapter that will have to be worked through before
this actually occurs. It Is unlikely that problems such as cultural
differences will ever be entirely overcome. Although it is probable
that actual tests can be designed to be culture free (in fact, a number
already exist for some neurobehavioral functions), the problem of
differences in attitudes to testing will probably never be overcome.
Nevertheless the position is definitely better now than at the end
of the 1970s because the amount of international exchange and
collaboration has increased markedly. The field of neurobehavioral
toxicology is currently in the position of being able to at least plan in
advance and guide the development of neuroto~c~city testing In countries
where it has not yet made much impact. This will take time, but the
opportunity to do so should be seized now.
REFERENCES
American Psychiatric Association. 1980. Diagnostic and Statistical Manual of Mental
Disorders (DSM III), third edition. Washington, D.C.
Brozek, J. 1978. Nutrition, malnutrition and behaviour. Annual Review of Psychology
29:157-177.
Cravioto, J., and E. R. Delicardie. 1973. Nutrition, behaviour and reaming. World
Reviews in Nutrition and Dietetics 16:80-96.
Hancock, P. A, and J. O. Pierce. 1985. Combined effects of heat and noise on human
performance: A review. American Industrial Hygiene Association Joumal 46:555-
566.
Hanninen, H. 1971. Psychological picture of manifest and latent carbon disulphide
poisoning. British Joumal of Industrial Medicine 28:374-385.
Lezak, M. D. 1983. Neuropsychological Assessment. New York: Oxford University
Press.
Williamson, A. M., B. Clarke, and C. Edmonds. 1987. The neurobehavioural effects of
professional abalone diving. British Joumal of Industrial Medicine 44:459~66.
OCR for page 344
Representative terms from entire chapter:
neurotoxicity testing
