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Issues in the Development of Neurobehavioral Toxicity Tests in India Vinod Behari Saxena Developing countries are a vast entity and each country has its own specific problems, geographical, economic, social, legal/policy, as well as technical, so far as occupational health is concerned. Each country has to explore the resources it can make available to support the development of neurobehavioral tests of toxicity for early detection of occupational health and hazards. Part IV of this volume, dealing with regional issues in the development of neurobehavioral toxicity tests, is concerned with future development of behavioral tests of neurotoxicity in occupational health. To understand the topic fully there are several issues to be discussed: 1. The status of research and development 2. Expected directions in the development of behavioral tests of neurotoxicity 3. Barriers to the development of behavioral tests of neurotoxicity 4. Recommendations for the development of behavioral tests of neurotoxicity These will be considered within the general context of the Indian subcontinent. 322
NEUROBEHAVIORAL TOXICITY TESTS IN INDIA STATUS OF ENVIRONMENTAL RESEARCH AND DEVELOPMENT IN INDIA Recognition of a Need 323 India is well recognized as being among the developing countries of Asia. It is comparable to developed countries only in the field of space research. Basically it is an agricultural country that is now advancing very rapidly in the development of its industrial sector. Only in one state Uttar Pradesh has the number of industries (both private and public) approximately doubled within a span of six years (from 5,334 in 1981 to 9,529 in 1987~. Cottage industries also play an important role. One can very easily consider that an explosion of industrial development in India has occurred during the last decade. With industrial development the number of workers in industries has also approximately doubled. Statistics for 1983 (Labor Bureau, 1985) show that the labor population was 33.4 percent of the total population in the country as a whole, whereas it was 29.2 percent of the population in Uttar Pradesh. With the advancement of scientific methodology in agriculture and industries, new technology is being adopted everywhere in the country to increase production and to save precious time and labor. A large number of chemicals are being introduced, but unlike the developed countries, the harmful side effects of this industrialization are not being taken into consideration. Workers engaged in, and affected by, toxic substances are not given protection by their employers, be they government or private organizations. Due to lack of standards in health, hygiene, and safety- practices, occupational health is very low on the list of national priorities. Workers are exposed to relatively high doses of neurotoxic substances without adequate protection. Because of ignorance and, possibly, of no way to cope with the problems, very little or no attention is paid to early neurobehavioral changes. The first awareness of pollution and the need for environmental protection started with the great jaundice epidemic of 1956 in Delhi, resulting in the establishment of the Central Public Health Engineer- ing Research Institute (CPHERI) at Nagpur in December 195~lanuary 1959, and later as the National Environment Engineering Research Institute (NEERI) under the Council of Scientific and Industrial Researrh (CSIR). As an institution, NEERI has been a forerunner in the coun- try to focus attention on air, water, and land pollution. The second step in the environmental movement in India had, for all practical purposes, its beginning in 1972, the year of the Stockholm conference. During the last decade, the environmental movement
324 VINOD BEHARI SAXENA has also received legislative recognition in the form of laws for the prevention of water and air pollution. Promulgations of the Environment (Protection) Act of 1980 and the Factories Amendment Act of 1987 are particularly important developments because they seek to make the agencies responsible for the monitoring and control of pollution more effective by conferring on them greater powers than they have hitherto enjoyed. The third phase started in 1984 when the methyl isocyanide (MIC) accident of the Bhopal gas tragedy on December 2-3 forced the gov- ernment and other agencies to review occupational health and safety programs and created awareness in the general population about the effects of toxic substances. Epidemiological studies have been carried out since the MIC accident, but because of ignorance of behavioral toxicology, not much attention has been paid to neurobehavioral changes, which are not being assessed by any well-developed neurobehavioral test battery. Centers for Occupational Health and Safety In the field of occupational health and safety, the five following institutes/centers have been operating in India during the last few decades, but none has a separate department/unit dealing with neurobehavioral changes resulting from exposure to toxic substances and their assessment with the help of a neurobehavioral test battery: 1. National Institute of Occupational Health (NIOH); Indian Council of Medical Research, Ahmadabad 2. All India Institute of Hygiene and Public Health, Calcutta 3. Industrial Toxicology Research Centre (ITRC), Lucknow 4. Central Labour Institute (CLI), Bombay 5. Occupational Health Services (OHS), Bharat Heavy Electricals, Ltd. Centre, Tiruchirappalli These institutes are working mainly in the field of epidemiological studies, animal studies, neurological studies, and general occupational health and hygiene problems. Only the OHS center of BHEL and one OHS unit of ITRC have been carrying out some work in neurobehavioral toxicology since 1980 but without developing their own test battery or even with any total battery from the developed countries. Not until December 1987 and January 1988 did NIGH, Ahmadabad, establish a Department of Behavioral Toxicology, which will begin studies in the near future. The health problems of Indian workers are especially serious. Workers are more prone to accidents, etc., because many are illiterate or, even
NEUROBEHAVIORAL TOXICITY TESTS IN INDIA 325 when literate, are not aware that the environment in which they are working may, in any way, be harmful to them. They continue working without any awareness of the toxicity of their work environment. The situation is further complicated by the fact that the majority of owners of industries are themselves not aware of the danger to which they are exposing their employees. The role of psychology in the industrial setup is restricted to placing the right worker on the right job and to matters affecting productivity. Psychologists have little to do with detection of toxic effects caused by exposure of workers to toxic substances in industries and in agriculture. When such are the state of awareness and concerns about occupa- tional health" where even conventional precautions and care are not being observed the very limited status of the developing field of behavioral toxicology can easily be understood. The field has just reached the country, and the majority of scientists, policy makers, and industrialists, as well as the general public, do not even know that such a field exists, let alone applying it. Moreover, when people are told about them, studies in neurobehavioral toxicology are generally considered an extravagance. In brief, it can be stated that research work in this field is in an early budding stage. DEVELOPMENT OF A PROGRAM AT KANPUR UNIVERSITY It was not until 1980 that the Department of Psychology, Pandit Prithi Nath (PPN) College, Kanpur University, started work in this discipline, stimulated by the research work of Dr. Helena Hanninen. At present about six research investigators are working in this field. Most of the research is ex post facto field studies planned to assess effects of various toxic substances on different behavioral parameters with the help of neurobehavioral tests. Up to the present time, the effects of the following toxins have been explored: organic solvents, larvicides, pesticides, and insecticides; lead, chromium oxide, and carbon monoxide. Findings of five studies are summarized here in brief as examples of research that can be helpful in initiating a systematic program during its early stages of development. All the studies were conducted not with the objective of treatment referral or withdrawal from exposure, but to detect whether toxic substances in the workplace had caused neurobehavioral changes in a population of exposed workers. The exposures had been to chronic low doses over long terms. No environmental monitoring or biomonitoring was done for want of facilities. All tests used in the studies were selected in view of the objectives of studies and guide-
326 VINOD BEHARI SAXENA lines proposed for the selection of tests by the World Health Organi- zation (WHO): · Tests known to measure functions that are affected by several neurotoxic agents · Tests that have yielded positive results in earlier, corresponding studies Consideration of costs in terms of time and money · Tests that are reasonably motivating and relatively indepen- dent of the subjects' cultural and educational backgrounds. Out of the ten proposed functional domains, only four to five have been studied for want of test facilities and practical requirements necessary for the study. One of the studies was conducted by Kumar and Saxena (1985~. It was designed to look at the effect of long-term exposure to organic solvents on the performance of two groups of workers (100 workers in each group) from gasoline filling stations and the paint industry. Performance was measured by using a psychological test battery containing Benton Visual Retention test, Bourdon-Wiersma Vigilance test, Santa Ana Dexterity test, and a screening questionnaire. Results were compared with those of comparable groups of unexposed workers matched on mean age, education, and salary, with exposure duration of (1) up to five years and (2) more than five years. The results of the study revealed that exposure to gasoline is more harmful for memory (immediate, as well as delayed) than exposure to paint solvents when exposures were as long as five years. Both chemicals became equally toxic when the duration of exposure increased, although gasoline caused no further impairment whereas paint solvent led to continuing deterioration. In perceptional accuracy/vigilance measures the same phenomenon was found. In this case, however, gasoline caused im- pairment but not as much as paint solvents. As the duration of exposure increased, gasoline remained the more toxic of the two. This trend was not found in cases of manual dexterity, where both solvents were equally toxic irrespective of the duration of exposure and both maintained their toxicity even after five years. It may be concluded that exposure to both solvents causes impairment of behavioral functions in the exposed worker, with gasoline being the more harmful of the two at least in case of immediate memory and perceptual accuracy. Another of the studies (Singh and Saxena, 1987a) was designed to determine the effect of long-term, low-dose exposure to a mixture of organic solvents (used as thinner for paint) on memory and subjective symptoms. The scores of 24 spray painters from an automobile workshop
NEUROBEHAVIORAL TOXICITY TESTS IN INDIA 327 were recorded on Postgraduate Institute (PGI) memory questionnaire and a questionnaire on subjective symptoms. These results were compared with the scores of a group of workers from the upholstery section of the same workshop. Significant differences were found in four (memory total, mental balance, concentration, and recall) of ten aspects of memory, with a better performance by the unexposed workers. On comparing the extent of impairment of different aspects of memory, attention and concentration (digit span) were found to be most affected. Sub- jective symptoms did not clearly differentiate between the two samples, significant differences were found in only 3 of 40 symptoms. In total, however, the results indicate some deterioration in psychological functioning of workers as a result of exposure to organic solvents. Exposure to Larvicides, Pesticides, and Insecticides Singh and Saxena (1987b) have reported results of yet another study planned to measure possible effects of long-term exposure to larvicide (organophosphate), fenvalerate (synthetic pyrethroid), and Gammexane (organochlorine). The performances of three groups of workers (100, 30, and 22, respectively) from related departments were measured on a psychological test battery comprising PGI memory test, Santa Ana Dex- terity test, Bourdon-Wiersma Vigilance test, a questionnaire on subjective symptoms, and a screening questionnaire. The results were compared with those of a comparable group of unexposed workers matched on mean age, education, and salary. Results were as follows: (1) The group exposed to larvicide was found to have significantly poorer per- formance on memory, vigilance, and dexterity tests than the control group. The exposed workers also reported certain subjective symptoms indicating that exposure to larvicide impaired psychological function- ing. (2) The group exposed to fenvalerate was found to be affected in measures of memory, manual dexterity, and perceptual accuracy. (3) The third group exposed to Gammexane was found to have impaired memory, manual dexterity, and vigilance. They also reported the pres- ence of such symptoms as hostility and destructiveness. Comparisons among the three exposed groups were made with the help of multiple regression analysis in which the effect of poten- tially confounding variables such as age and education were partialled out. All three groups of compounds were found capable of causing impairment in the psychological functioning of workers, organophosphate compounds being the most toxic followed by organochlorine and synthetic pyrethroid compounds, respectively.
328 VINOD BEHARI SAXENA Exposures in the Leather Industry Siddiqi and Saxena (1988) studied on 300 workers, 250 of whom were occupationally exposed to chemicals used in the leather indus- try (50 workers for each stage of tanning: liming, pretanning, tan- ning, dying, and finishing) and 50 workers as a control group matched on mean age, education, salary, and length of service. Exposure du- ration was defined in terms of length of service (i.e., less than five years and more than five years). The following measures were used a screening questionnaire, the Santa Ana Dexterity test, a subjective symptoms questionnaire, and EPI. Results showed that exposure to chemicals in aB five stages of tanning causes impairments in behavioral functions of the workers. Exposure to chromium oxide during the tanning process had its most adverse effects on perceptual accuracy and manual dexterity. Remote memory, recent memory, and delayed recall were not affected. When results were interpreted in terms of exposure duration, it was observed that exposure up to five years caused impairment in the performance of workers on all the functional domains under study except remote memory and recent memory. Mental balance, digit span, delayed recall, immediate recall, retention of similar pairs, retention of dissimilar pairs, visual retention, and overall memory were affected by exposures even after five years. In brief, it may be stated that deterioration increases with increasing exposure in behaviors involving memory, manual dexterity, perceptual accuracy, subjective symptoms, and neuroticism. Effects of Exposure to Lead A study by Saxena and Saxena (1988) focused on effects of long- term, low-dose exposure to lead on the performance of 150 workers from a battery factory. Performance was measured by a psychologi- cal test battery comprising the Benton Visual Retention test, digit span, Bourdon-Wiersma Vigilance test, Santa Ana Dexterity test, EPI, and NSQ. These measures were compared with those of a control group of unexposed workers matched on mean age, education, and salary. Duration of exposure was (1) less than 5 years, (2) between 5 and 10 years, and (3) more than 10 years. The results established that exposure to lead was detrimental to measures of memory (both visual and auditory), perceptual accuracy/vigilance, and manual dexterity. The longer the duration of exposure, the greater was the impairment in these functional domains. Significantly lower levels of extroversion, neuroticism, tendermindedness, depression, and anxiety were observed in the unexposed group of workers than in exposed workers. Duration
NEUROBEHAVIORAL TOXICITY TESTS IN INDIA 329 of exposure differentially affected some but not all behaviors. For example, subjective symptoms (factitious behavior, suspiciousness, impatience, self-absorption, and attacking others) were significantly higher in the exposed group of workers than in the unexposed Ruin when the exposure duration was more than 10 years. -a--- =--~r EXPECTED DIRECTIONS IN THE DEVELOPMENT OF BEHAVIORAL TESTS OF NEUROTOXICITY Most of the tests in the studies described above were adopted from the test battery being used at the Institute of Occupational Health, Helsinki, and from that suggested by WHO. As far as the development of test batteries in India is concerned, the work done has been negli- gible. The only instrument developed so far is a questionnaire on subjective symptoms, which still needs standardization. It covers subjective symptoms related to affective behavior, ingestive behavior, social behavior, attention, arousal, and consciousness. We have studied the potential usefulness a long list of available psychological tests: intelligence, interest, adjustment, aptitude, job involvement and sat- isfaction, anxiety, and personality. We have examined questionnaires, projective tests, performance tests for motor ability (speed and coor- dination), and such standardized tests as WAIS, DAT, 16PF, EPI, TAT, and CAT. Our conclusion is that the majority of the tests are not applicable to the total population of the country because they are not culture free in their current forms and, more specifically, because they present language problems. Similarly, from the literature of behavioral toxicology it has been noticed that all agencies in developed countries involves! in studying the effects of neurobehavioral toxicity are using their own behavioral test batteries for different toxic substances. In the recent past, WHO has suggested a test battery that can be used and developed by all nations and services. This may be proper and applicable in nations where the working conditions and the control of occupational hazards are of high level. However, for certain regions/nations where little, if any, attention has been paid to such conditions, the working conditions are poor; regulations concerning exposure and control of occupational hazards are minimum; and occupational health care is not among the top priorities of government. In these developing regions, occupational health questions need deep and exhaustive exploration in view of the geographic, economic, social, psychological, and legal perspective of occupational health. Only after deciding about acceptable Threshold Limit Values (TLVs) for different toxic substances, can the WHO test battery be used, with suitable modifications and adaptations, for the
330 VINOD BEHARI SAXENA identification of workers adversely affected. It is evident that in so far as development and adaptation of neurobehavioral tests are con- cerned, developing countries have contributed nothing or very little. This is attributable not to a lack of willingness or the capability of researchers but rather to the unfavorable circumstances in developing countries that do not recognize the important contributions neuro- behavioral toxicology can- make to the prevention of tragic occupa- tional hazards. Thus it seems that a giant task lies ahead. If we really are to be on a par with developed countries, we will have to work hard. It is useful to consider some of the directions in which actions are now needed. Priority should be given to the development of a test battery for preliminary screening comprised of elementary tests cov- ering all the functional domains described by WHO. It should then be applied to find out the domains that are being affected by exposure to various toxic substances. This battery should be a general test battery to be used in all epidemiological studies. It should be easy to administer, of about half an hour's duration, and portable. The battery will be helpful in narrowing down the areas of psychological functions to be studied in depth. The construction, development, and adaptation of tools of a more sensitive nature, covering all the functional areas found during preliminary screening to be affected by various toxicants, are necessary. Guidelines prescribed by WHO should be taken into consideration. These tests should be sensitive enough to detect even the slightest behavioral disorder, and they should be applied periodically to screen out susceptible workers. It would be desirable if these tests could be used in laboratory studies and experimental research, with volunteers performing under various concentrations of the toxic substances being studied. In this way,-maximum allowable concentrations can be determined. Consideration should be given to the development of a test battery whose scores can be compared with tests being used in other countries. This is essential in order to encourage the exchange of technical knowledge, possibly saving time and money in needlessly replicating studies. Comparing our results with those of other countries earl provide checks on the validity and reliability of our tests and can make pos- sible the comparison of work conditions. The preparation of culture-free tests that can be used by different countries is another important consideration. Such instruments require preliminary trials to find out if they are culture free. These types of tests are essential because India is such a vast country having various subcultures, each with its own language, that if we want to enact uniform rules regarding occupational health services, a uniform screening battery is necessary.
NE UR OB EHA VIORAL TOXICITY TE S TS IN INDIA 331 In brief, it may be concluded that in the development of behav- ioral tests of neurotoxicity all tests must possess the following char- acteristics: (1) the tests should be simple to administer; (2) they must be unambiguous in interpretation; (3) measures derived from them must be indicators of nervous system dysfunction; (4) tests should be comprehensive; and (5) as far as possible, they should be culture free. BARRIERS TO TEST DEVELOPMENT The expected direction of development of neurobehavioral tests of neurotoxicity depends on overcoming a number of obstacles. Until- and unless- a suitable test development environment is created, with a interdisciplinary approach and coordinated research programs, the scientific and systematic development of tests will not be possible. There are several obstacles that need to be addressed before carrying out such a research program. These were discussed in depth by participants in the First Asian Conference on Behavioral Toxicology and Clinical Psychology arranged by the Department of Psychology, Kanpur, in January 1987 (Saxena, 1988~. They are summarized be- low. Public Awareness The first and most important constraint is the lack of awareness of neurobehavioral toxicology and its usefulness among persons who should be concerned. A favorable attitude toward the field and a policy of support by governments are a must. Neurobehavioral toxi- cologists can contribute significantly through research and publication in scientific journals. However, such works are not likely to reach beyond those involved in the field itself. Implementation of scientific findings is the responsibility of industry, labor, and human resource departments of the state and central governments. To create awareness among the population as a whole is primarily a function of government. Without this support, effective measures to assess risks and control exposures to toxic conditions are not possible. Interdisciplinary Coordination The modern scientific era is based on interdisciplinary approaches to the development of systematic bodies of knowledge. India, too, is using this approach in many fields, but the field of occupational health and safety is an exception. Engineering departments design safe ma- chines to minimize the risks of accident. Medical departments pro- vide medical care to the worker on the basis of manifest symptoms.
332 VINOD BEHARI SAXENA Social welfare departments engage in general social welfare activi- ties. There is no recognized role for psychologists in India except for the selection of workers. The government provides protection in cases of fatal and serious accidents only through compensation and general medical care un- der employment insurance schemes, facilities available only to regis- tered workers and not to daily wage earners or unregistered workers of many small and cottage industries. The importance of interdisciplinary coordination is especially ap- parent in relations between neurobehavioral toxicologists and medi- cal specialists. General medical personneleven those who are working as industrial medical officers are not ready to accept that behav- ioral tests of toxicity can detect neurological damage or that these tests can be used for the early detection of damage. Because, at present, all epidemiological studies are carried out by medical personnel, fuller understanding and collaboration between the two disciplines are essential if the development of behavioral tests of neurotoxicity is to be possible. Tack of Appropriate Standards The present baseline Maximum Allowable Concentrations (MACs) and Threshold Limit Values (TLV's) are based on the international standard indices. None have been established by Indian researchers for Indian workers. One reason is that there is no single agency for the nation as a whole to oversee the development of suitable standards. The only alternative is to apply standards established in other regions of the world which differ in many ways from conditions in India. We need to plan the development of suitable standards basically in provinces and industries where the risk of toxic exposures may be great. Implementation of research plans is totally different from planning them, of course. As noted earlier, a whole network of awareness, government policy, and interdisciplinary cooperation needs to be in place if satisfactory MACs and TLVs are to be established so that standards of occupational health and safety may be raised. Illiteracy Most of the population working in industry, specifically in min- ing, tobacco, and those industries where toxicants are used, is illiter- ate. Workers are often hesitant in responding to test batteries or questionnaires. A hidden fear is that, if they fail on the tests, they will be removed from their jobs. Thus, both the employee and the
NEUROBEHAVIORAL TOXICITY TESTS IN INDIA 333 employer are hesitant to cooperate in carrying out research. More- over, there are certain taboos prevailing as far as mental health is concerned, and workers are especially sensitive to questions related to mood, affect, etc. Drug Abuse and Stress As in other developing countries, Indian workers suffer from mal- nutrition, drug abuse, and the like. So it is difficult to ascertain whether the particular dysfunctioning observed in a person occurs because of exposure to a toxicant, because the worker is a drug addict, or because the worker's general health is extremely poor. Similarly, it is difficult to isolate the effects of heat, noise, and other stresses from the effects of exposures to toxic substances. This makes the development and standardization of tests and the comparison of test results difficult. Control of Exposure The lack of awareness of neurobehavioral toxicology in India has meant that volunteers are not readily available to assist in the devel- opment of appropriate tests. The development of sensitive tests and the assessment of reactions to varying concentrations of potentially toxic substances would be facilitated if experimental studies could be conducted. Field studies are also difficult to conduct with full accuracy and effectiveness because (1) concentration levels of toxic substances in industry are variable over both short and long durations; (2) it cannot be said with certainty that a worker is exposed to only one toxic substance even in the workplace, and he may also reside in a highly polluted area; and (3) it is difficult to find comparable control groups of unexposed workers from the same industry. Financial Support Neurobehavioral toxicologists do not get financial assistance from any government or social agencies. Without support, the development, standardization, and adaptation of behavioral tests of neurotoxicity are not possible. Without public or private financial support the development of neurobehavioral toxicology in India will be slow and will never come up to par with the state of the discipline in devel- oped countries.
334 VINOD BEHARI SAXENA RECOMMENDATIONS FOR DEVELOPING COUNTRIES In view of the state of development of behavioral tests of neuro- toxicity and the facilities available in developing countries the fol- lowing recommendations are made. Training and Education The most important factors indicating the need for training and education in neurobehavioral toxicology are the lack of awareness about neurotoxic chemicals and the shortage of trained personnel in developing countries. As with occupational health in general, three levels of education and training are needed: public awareness, training for the specific procedures, and professional specialization. It is well recognized that developing countries differ widely in their ability to fulfill these needs. To create public awareness of neurobehavioral toxicology is a matter of general education; the objective is to provide an understanding of the principles and contributions this field may make in fostering correct attitudes in the workplace, where exposure to neurotoxic materials may occur, and to permit proper participation in any preventive action taken. The target groups include legislators, policy makers, managers, and workers. Specific task training may include administrators, managers, workers, designers, medical.and paramedical personnel, chemists and engineers, and occupational health and safety technicians. Specialization involves the education of fully qualified professionals in the field of neurobehavioral toxicology. Training programs in neurobehavioral toxicology should be di- rected to existing problems and to the current level of practice of occupational health in general and neurobehavioral toxicology in particular. When training programs are established, the development of behavioral tests of neurotoxicity and their application will be greatly facilitated. An important step can be taken when agencies of developed countries and international agencies such as WHO hold workshops, seminars, and conferences to support the objectives discussed above and also to train persons for the further development of neurobehavioral tests. Inclusion of Neurobehavioral Toxicology as a Full Partner in Occupational Health Programs Occupational health programs differ among developing countries and range from very early to relatively advanced stages. Neurobehavioral
NE UROB EHA VIORAL TOXICITY TE S TS IN INDIA 335 toxicology needs to be included as a part of occupational health prac- tice regardless of its stage of development in a country. This principle can only be followed if the practical aspects of neurobehavioral toxi- cology are explained and implemented through appropriate actions at national levels. The World Health Organization and the Interna- tional Labor Organization should use their influence until this goal is achieved. Applied Research Applied research is needed in developing countries to clarify the actual magnitude of the problems surrounding the development of behavioral tests of neurotoxicity. Research should focus on applied rather than basic questions. Developing countries have to learn from both the positive and the negative experiences of the developed nations. They should not repeat the mistakes made by the latter but should attempt to take shorter routes to reach a stage of modern occupational health care appropriate for their special needs. Communication Networks Development of test batteries is essential both for preliminary screening and for more extensive investigation. Comparison with findings obtained in other countries can facilitate the process. For this purpose it would seem advisable to encourage the creation of communication networks both internally and internationally. A center should be established in each developing country by appropriate international organizations, with the responsibility of fostering the development of neurobehavioral tests. Such centers should exchange information, passing it along to researchers working on the development of neurobehavioral tests. Each center should also get feedback from field workers and the results obtained from the development of such tests. Thus, the exchange of knowledge within a country and among countries will facilitate the development of usable and acceptable behavioral tests of neurotoxicity internationally. REFERENCES Kumar, P., and V. B. Saxena. 1985. Disturbances in Psychological Functions of Workers Occupationally Exposed to Organic Solvent. Unpublished doctoral thesis, Kanpur University, India. Labour Bureau. 1985. Pocket Book of Labour Statistics. Chandigarh, India: Ministry of Labour and Rehabilitation, Government of India.
336 VINOD BEHARI SAXENA Saxena, A., and V. B. Saxena. 1988. Behavioral Effects of Occupational Exposure to Lead. Unpublished doctoral thesis, Kanpur University, India. Saxena, V. B., ed. 1988. Proceedings of the First Asian Conference on Behavioral Toxicology and Clinical Psychology. Kanpur, India: Alka Printers. Siddiqi, J., and V. B. Saxena. 1988. Behavioral Disorders in Workers Exposed to Chemicals (Chromium Oxide and Dyes) Used in Leather Industry. Unpublished doctoral thesis, Kanpur University, India. Singh, J., and V. B. Saxena. 1987a. Memory and subjective symptoms in automobile painters. Indian Psychological Review 32(2):5-12. Singh, J., and V. B. Saxena. 1987b. Psychological Performance and Subjective Symp- toms of Workers Occupationally Exposed to Past Control Substances. Unpublished doctoral thesis, Kanpur University, India.
