Opinion ID: 2637824
Heading Depth: 5
Heading Rank: 2

Heading: Defendant's mental health

Text: Dr. Peter Russell, a neuropsychologist, gave defendant a series of standardized tests as part of a neuropsychological evaluation. Before testing defendant, Dr. Russell reviewed his school records, medical records, arrest reports, and other legal records. On the Wechsler Adult Intelligence Scale, defendant scored an overall IQ of 107, equivalent to the 68th percentile, within the normal range of intelligence. Defendant performed within the normal range in both his immediate verbal and visual memory tests. He also performed exceptionally well on some of his nonverbal visual organizational skills tests and other visual perception and visual memory tests. Dr. Russell's tests showed no indications that any of defendant's memory or sensory functions were impaired. Dr. Russell's testing, however, revealed a discrepancy between defendant's verbal ability, which tested at the 45th percentile, and his nonverbal ability, which tested at the 90th percentile. Dr. Russell believed that this discrepancy could reflect a problem with the English language itself, difficulty with language-related reasoning ability, auditory processing problems, or defendant's education level, which was the equivalent of an eighth- or ninth-grade education. He also acknowledged that the discrepancy could be the result of antisocial personality disorder, but did not test defendant for any personality disorders. Dr. Russell also believed that defendant may have neurological problems because, although he is right handed, he performed finger tapping tests better with his nondominant left hand. Dr. Russell acknowledged, however, that defendant may have performed poorly on this test because he had previously suffered a dislocated shoulder, an injury that often results in residual nerve impingement. In addition, defendant performed atypically on the trail-making test, which required him to draw a line connecting randomly distributed circles, first in alphabetical order and then in alphanumeric order. Although defendant made no mistakes, he performed the easier alphabetical ordering slower than normal, and the more difficult alphanumerical ordering at a normal speed. Dr. Russell believed this discrepancy could also indicate neurological problems. Based on the test results, Dr. Russell believed defendant may have neurological impairment in his anterior frontal lobe, especially the right frontal lobe. According to Dr. Russell, the frontal lobe is the part of the brain important for responsiveness, abstract reasoning, the ability to react to stimuli, and to interpret sensory information from other pathways. People with frontal lobe damage can have difficulty controlling impulses. Dr. Russell was uncertain as to the cause of defendant's impairment, but noted that defendant's hospital emergency room records reflected he may have suffered head trauma as a result of a fall during a police chase. In addition, he noted that using methamphetamine and inhaling solvents are known to cause neurological damage and that defendant's use of solvents coincided fairly closely with the time he quit going to school. Dr. Russell acknowledged that defendant's shoulder injury and his poor school performance could have contributed to his lower scores in some verbal and motor skills tests, but he believed these conditions could not explain all of his test results. He also explained that persons with normal IQ scores can still suffer from brain damage because the IQ test is a measure of global functioning and does not target a specific part of the brain. Therefore, Dr. Russell ordered a positron-emission tomography scan, or PET scan, which is essentially an X-ray imaging of the brain, to see whether defendant's brain functioned abnormally. Dr. Joseph Wu, clinical director of the Brain Imaging Center and an associate professor in the School of Medicine at the University of California at Irvine, performed a PET scan on defendant. A PET scan is designed to reveal brain functioning in a conscious patient. In a PET scan, the patient is given a radioactive sugar that is designed to be consumed by active portions of the brain. The PET scan can detect different levels of the radioactive sugar as parts of the brain switch from being relatively inactive to active while the patient is asked to perform standardized tasks. In this fashion, the PET scan can present a recorded visual map of brain activity. According to Dr. Wu, although the usefulness of PET scans has been questioned, he believed the medical community now considers PET scans to be an accurate and reliable test of brain function and brain activity that can be useful in evaluating conditions created by inhalant exposure. In Dr. Wu's opinion, defendant's PET scan revealed brain abnormalities consistent with neurological damage from inhaling solvents. According to Dr. Wu, defendant had an unusually low degree of activity in the front part of his brainin particular, the parietal lobe area and in his orbital frontal cortex. Consequently, defendant's brain activity was the reverse of a normal functioning pattern, with more activity in the back of his brain. According to Dr. Wu, this reversal can occur as undamaged parts of the brain increase their activity to try to compensate for damaged portions. Dr. Wu believed that defendant's abnormalities were consistent with frontal lobe syndrome, which can result in poor judgment, inappropriate behavior, and an inability to defer gratification and control inappropriate aggressive impulses. These abnormalities can also result in impulsive decisionmaking without considering long-term consequences. He also believed the abnormalities could result in decreased control or regulation of emotions or aggression as well, but would not hinder the ability to have normal emotions, including compassion. Dr. Wu thought his findings of brain damage correlated with Dr. Russell's neuropsychological evaluation. Dr. Wu explained that inhaling solvents can dissolve fatty protective tissues in the brain. He noted that exposure to solvents does not necessarily diminish a person's intelligence, but exposure during adolescence would affect the maturation of the frontal lobe, causing problems with impulsivity and poor judgment. The use of marijuana, alcohol, and methamphetamine by a person who also used solvents would further diminish that person's inhibitions and behavioral control. Dr. Wu believed defendant would be able to control his behavior if he were in a highly structured setting like a state prison.