New York State TrueAllele® Casework Validation Study

DNA evidence can pose interpretation challenges, particularly with low‐level or mixed samples. It would be desirable to make full use of the quantitative data, consider every genotype possibility, and objectively produce accurate and reproducible DNA match results. Probabilistic genotype computing is designed to achieve these goals. This validation study assessed TrueAllele^® probabilistic computer interpretation on 368 evidence items in 41 test cases and compared the results with human review of the same data. Whenever there was a human result, the computer's genotype was concordant. Further, the computer produced a match statistic on 81 mixture items (for 87 inferred matching genotypes) in the test cases, while human review reported a statistic on 25 of these items (30.9%). Using match statistics to quantify information, probabilistic genotyping was shown to be sensitive, specific, and reproducible. These results demonstrate that objective probabilistic genotyping of biological evidence can reliably preserve DNA identification information.     

Decision making in a schizophrenic population

Over the past decade, competence to make decisions has become a prominent topic in forensic psychology. We employed a gambling paradigm to measure ability to weigh risks, benefits, and probabilities in an internally consistent manner. Decision-making behavior of chronic, involuntarily committed schizophrenic inpatients was compared to outpatient schizophrenics and first-degree relatives of the patients. We found significant differences between inpatients and non-mentally-ill relatives, and between inpatient and outpatient schizophrenics. When WAIS-R Vocabulary subtest score was statistically controlled,no significant differences between any of the groups remained. Vocabulary x group interactions revealed that Vocabulary subtest predicted decision-making behavior for outpatients and controls, but not inpatients. Severity of psychiatric symptoms and number of prior hospitalizations predicted decision-making behavior for inpatient schizophrenics. Results suggest that competence assessments that rely primarily on verbal abilities may be inadequate to assess competence in acutely ill psychiatric patients.     

Results of a proposed breath alcohol proficiency test program

Although proficiency test programs have long been used in both clinical and forensic laboratories, they have not found uniform application in forensic breath alcohol programs. An initial effort to develop a proficiency test program appropriate to forensic breath alcohol analysis is described herein. A total of 11 jurisdictions participated in which 27 modern instruments were evaluated. Five wet bath simulator solutions with ethanol vapor concentrations ranging from 0.0254 to 0.2659 g/210 L were sent to participating programs, instructing them to perform n = 10 measurements on each solution using the same instrument. Four of the solutions contained ethanol only and one contained ethanol mixed with acetone. The systematic errors for all instruments ranged from -11.3% to +11.4% while the coefficient of variations ranged from zero to 6.1%. A components-of-variance analysis revealed at least 79% of the total variance as being due to the between-instrument component for all concentrations. Improving proficiency test program development should consider: (1) clear protocol instructions, (2) frequency of proficiency testing, (3) use lower concentrations for determining limits-of-detection and -quantitation, etc. Despite the lack of a biological component, proficiency test participation should enhance the credibility of forensic breath test programs.     

Changing patterns of drug and alcohol use in fatally injured drivers in Washington State

We have previously reported on patterns of drug and alcohol use in fatally injured drivers in Washington State. Here we revisit that population to examine how drug use patterns have changed in the intervening 9 years. Blood and serum specimens from drivers who died within 4 h of a traffic accident between February 1, 2001, and January 31, 2002, were analyzed for illicit and therapeutic drugs and alcohol. Drugs when present were quantitated. Samples suitable for testing were obtained from 370 fatally injured drivers. Alcohol was detected above 0.01 g/100 mL in 41% of cases. The mean alcohol concentration for those cases was 0.17 g/100 mL (range 0.02-0.39 g/100 mL). Central nervous system (CNS) active drugs were detected in 144 (39%) cases. CNS depressants including carisoprodol, diazepam, hydrocodone, diphenhydramine, amitriptyline, and others were detected in 52 cases (14.1%), cannabinoids were detected in 47 cases (12.7%), CNS stimulants (cocaine and amphetamines) were detected in 36 cases (9.7%), and narcotic analgesics (excluding morphine which is often administered iatrogenically in trauma cases) were detected in 12 cases (3.2%). For those cases which tested positive for alcohol c. 40% had other drugs present which have the potential to cause or contribute to the driver's impairment. Our report also considers the blood drug concentrations in the context of their interpretability with respect to driving impairment. The data reveal that over the past decade, while alcohol use has declined, some drug use, notably methamphetamine, has increased significantly (from 1.89% to 4.86% of fatally injured drivers) between 1992 and 2002. Combined drug and alcohol use is a very significant pattern in this population and is probably overlooked in DUI enforcement programs.     

Structured Assessment of Correctional Adaptation (SACA): a measure of the impact of incarceration on the mentally ill in a therapeutic setting

Clinicians have observed that psychiatric patients with correctional histories evidence attitudes and behaviors that seem adaptive in penal environments but are maladaptive in mental health settings. This study sought to assess the reliability and concurrent validity of a rating scale designed to measure correctional adaptation using a sample of 64 patients from a state psychiatric hospital. Scale ratings were obtained through structured interviews, whereas predictor variables were gleaned from chart review and self-report. The scale demonstrated good interrater reliability (ICC = .83) and acceptable internal consistency (alpha= .67). Of the variables evaluated, two were significantly correlated with Structured Assessment of Correctional Adaptation (SACA) total scores, total months sentenced to prison or jail (r = .26), and frequency of disciplinary tickets while in prison or jail (r = .31). Stepwise regression analyses revealed only the latter variable significantly predicted SACA score (R = .31), F(1, 58) = 6.27, p < .05. Clinical implications of these findings, the scale, and the construct of correctional adaptation are discussed.     

A comparison of carboxyhemoglobin saturation values in postmortem heart blood and peripheral blood specimens

The following is a study conducted to determine whether there was any significant difference in carboxyhemoglobin (COHb) saturation levels between the heart blood and blood collected from a peripheral site. The average heart blood to peripheral blood COHb saturation level ratio in the 42 cases studied was 1.09. Sixty-two percent (26 of 42) of the cases had a heart blood to peripheral blood ratio between 0.9 and 1.1; 74% (31 of 42) had a ratio between 0.8 and 1.2. Eighty-three percent (35 of 42) had a ratio between 0.7 and 1.3. There were four cases where the heart blood to peripheral blood ratio was either below 0.6 or greater than 1.4. The differences between the two sites were not statistically significant.