Forensic Neuropsychology

Forensic Neuropsychological Evaluation involves the application of neuropsychological assessment methods to the examination of criminal or civil litigants. A forensic neuropsychology expert presents reliable/valid assessment data about the relationship between neurocognitive dysfunction / neuropathology and the behavioral and/or cognitive issues related to legal proceedings. Forensic experts competent in neuropsychological assessment will often examine criminal defendants relevant to competency, sanity, and mitigation. Some research indicates that various offender groups have a significant chance of experiencing a history of head injury (Table 1).

Table 1: Prevalence of Head Injury in Offender Groups (Miller, 2002)
StudyNNature of GroupRate
Bach-y-Rita & Veno (1974)62Habitually violent offenders61%
Blake et al. (1995)31Murderers10%
DelBello et al. (1999)25Sexual Offenders36%
Frierson et al. (1998)54Murderers24%
Gibben et al. (1959)72Severely psychopathic criminals40%
Lewis et al. (1986)15Convicts on “death row”67%
Lewis et al. (1988)14Convicts on “death row” sentenced as juveniles58%
Lumsden et al. (1998)97Consecutive admissions to UK special hospital42%
Martell (1992)50Inmates in maximum security hospital for offenders22%

E. Miller. (2002). Brain injury as a contributing factor in offending. In J.Glicksohn Ed.THE NEUROBIOLOGY OF CRIMINAL BEHAVIOR.

Mitigating Environmental Factors Breeding Neuropsychological Impairment

More often than not, defendants charged with homicide have been exposed to various risk factors in their environment that generate cognitive, neuropsychological, and organic brain impairment. Some relevant risk factors include the following:

  • Young maternal age during pregnancy.
  • Maternal alcohol, nicotine, drug use and poor diet and medical care during pregnancy.
  • Fetal maldevelopment, minor physical abnormalities, Fetal Alcohol Syndrome.
  • Pregnancy and birth complications.
  • Parental criminality and substance abuse.
  • Domestic violence to mother during pregnancy.
  • Poor offspring nutrition and medical care.
  • Large family size.
  • Exposure to parental physical abuse and emotional neglect.
  • Exposure to deplorable home conditions.
  • Exposure to toxins, lead, parasites, and/or infection.
  • Poor socioeconomic conditions and deficient parental and offspring education.
  • Substance abuse and dependence history; brain dysfunction is more common amongst substance users. Substance abusers are more likely to have preexisting neurological conditions and deal with conditions by use of substances.
  • Experience of violent victimization which could include head injury and symptoms of Posttraumatic Stress Disorder (PTSD).

The following list highlights global frontal lobe brain behavior responsibilities that potentially have an impact on the outcome of criminality and violence:

  • Sustaining attention and concentration,
  • Understanding, processing, and communicating information,
  • Planning, organizing, and initiating thoughts and behavior,
  • Understanding others’ reactions,
  • Abstracting and reasoning,
  • Controlling impulses/stopping behavior/emotional regulation,
  • Inhibiting unsuccessfully, inappropriate, or impulsive behaviors,
  • Using knowledge to regulate behavior,
  • Behavioral flexibility to changing contingencies,
  • Modulating behavior in light of expected consequences,
  • Distraction from persisting with appropriate behavior,
  • Lacking appreciation of impact of behaviors onto others,
  • Manipulation of learned and stored information when making decisions.