Neurological, neurophysiological and neuropsychological effects of exposure to pesticides

ABSTRACT

The present study is a cross sectional field study aimed to investigate long-term effects of pesticides on the nervous system. It was conducted in citrus farm in Sahel Sleim, Assuit Govemerate. It was composed of 3 groups I .Directly exposed group which consisted of 30 men using organophosphorus compounds [OP]. They were involved directly in application of pesticides for variable durations of time. 2. Indirectly exposed group consisted of 30 men living at the same environment and exposed indirectly to the same compounds through water, air, vegetables and milk. 3. Control group, consisted of 30 men who were never exposed occupationally or environmentally to pesticides, they lived in urban areas. All groups were subjected to clinical assessment, neuropsychological examination with Mini mental state examination [MMSE], Wechsler memory scale [WMS], and Beck's depression scale. Neurophysiological assessment [Event related pattern [P300], Visual evoked potential [VEP] and Brain stem auditory evoked potential [AEP] to detect minor and early affection of nervous system due to exposure to pesticides. The neurological symptoms [Asthenia, headache, and vertigo, dizziness, blurring of vision, numbness and tingling] were more frequent in the directly exposed group than other groups and the most frequent symptoms were dizziness and blurring of vision, which were present in 23.33%. Neurological signs [superficial sensory loss, deep sensory loss, decrease or lost ankle or deep reflexes, muscle weakness and trophic changes] were more frequent in directly exposed group than the other groups, and this increase is positively correlated to the duration of exposure to pesticides. The most frequent findings were abdominal complaint and respiratory signs, which were present in 30%. General signs and symptoms [abdominal, respiratory, topical and sexual] were not showing statistically significant differences between the three groups. There was prolonged latency of P300 in directly and indirectly exposed group than in control group, but the difference was not statistically significant, except in reaction time [P<0.02]. Auditory evoked potential demonstrated that there was statistically significant difference between directly exposed group and control group in the absolute latency of wave 111, 1 V, and V in both right and left sides. There was statistically significant difference between direct and indirect exposed groups in absolute latency of wave IV, V of both right and left sides. Visual evoked potential had showed a statistically significant difference [in latency of binocular YEP] between directly and indirectly exposed groups "in one hand "and non-exposed group" in the other hand". Mini mental state examination and Wechsler memory scale showed that there was affection in different components of them in relation to direct or indirect exposure to pesticides. This means that memory is affected by long term exposure to pesticides and this effect is more extensive when exposure is direct. Results of Beck's depression scale were showed a higher incidence of depression. in conclusion, the prolonged low level exposure to the organophosphorus compound can affect the nervous system, and this appeared in directly exposed people via formulation or handling of these compounds and the appeared in the form of increasing the frequencies of neurological as well as general symptoms and signs. Effects of pesticides exposure were also include brainstem dysfunction, memory, cognitive impairment and increased risk of depression as seen in different neurophysiological and neuropsychological testing