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Neuropsychological Evaluation
  of Bystander Exposure to Pesticides.

Raymond M. Singer
Independent Practice, Santa Fe, New Mexico,

and New York, New York


Background: There are reports in the literature of long-term
neurobehavioral dysfunction in persons with pesticide exposure,
primarily in occupational settings. This report presents data
concerning a subject with non-occupational and apparently
single-incident exposure

A home with open windows and a property were sprayed by helicopter
with a mixture of pesticides, including chlorpyrifos, a carbamate
(carbofuran) and an organophosphate.

Three dogs on the property, fed from separate cans of food, were
vomiting and listless, and were diagnosed by their veterinarian with
pesticide poisoning.

The subject reported initial symptoms of anxiety, itching on face
which spread over her body, dizziness and forgetfulness, with sleep
frequently interrupted around 2-3 AM with symptoms of breathlessness, followed by numb hands and feet and a feeling of "blacking out".

She continued to reside in the home during the time when the pesticides
were still potent. Her primary symptoms at the time of this examination,
three years later, were disabling chemical sensitivity, along with sleep apnea-like episodes, and memory problems. ...

Methods: Physical examination which ruled out other causes of the
symptoms, medical record review, brain MRI and neuropsychological

Results: Brain MRI showed diffuse scattered foci of increased signal
intensity in the subcortical and periventricular white matter tracts.
Organophosphate pesticides are known to cause degeneration of
the myelin.

From normal or better pre-exposure function, declines in function included arithmetic (5th %); Digit Symbol and Symbol Search (9th %); visual memory (BVRT, 11 errors); Embedded Figures (1st %); Paired Associates Learning
(1st %) and logical memory (1st %).

Personality testing showed no personality disorder.

[Note:  Below are several paragraphs from the text of the article which
describe in more detail the patient's actual loss of cognitive skills.

   Her pre-exposure GPA was 3.7, and she had been a member of
   Phi Theta Kappa (National Honor Society) and Sigma Tau Delta
   (National English Honor Society). The subject was working at
   home at the time of exposure.

   Current neurobehavioral testing revealed a FSIQ at the 25th
   percentile; performance IQ at the 18th percentile; processing
   speed at the 8th percentile; psychomotor speed at the 9th
   percentile; arithmetic at the 5th percentile.

   A decline in overall intelligence was detected, along with
   specific deficits in arithmetic skills, psychomotor speed,
   visual perception (visual detection skills), and incidental
   memory. When looking at index scores, deficits can be seen
   in perceptual organization and processing speed.

   The Benton Visual Retention Test found strong indication
   of acquired impairment of cognitive functioning (11 errors).
   An Embedded Figures Test which evaluates the ability to
   detect visual figure-ground relationships found performance
   below the 1st percentile.

   The Expanded Paired Associate Test, which evaluates verbal
   learning ability, found deficits in immediate recall (1st %) and
   delayed recall (11th %).

   Auditory information processing and tracking was below
   the 1st %.  Logical memory ability, both immediate and delayed,
   was reduced by half. There was no evidence of psychoses,
   distortion or malingering based upon numerous tests of these

Conclusion: Doctors need to be aware that pesticide exposure can lead
to permanent neuropsychological deficits, even with a "single" exposure.
Brain dysfunctions from neurotoxicity can be revealed with appropriate neuropsychological testing.

Click here  for the entire text Dr. Raymond Singer's article.

1. Singer, R. (1999, expected). Neuropsychological evaluation of bystander exposure to pesticides. The Journal of Neuropsychiatry and Clinical Neurosciences, 9, 1.

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