We all know someone who has experienced cognitive and behavioural changes associated with dementia and more specifically, frontotemporal degeneration, caused by progressive cell loss in the brain’s frontal lobe. The process is at times gradual, and can start long before it is identified, diagnosed and treated. For the period when a person has not been identified as having a frontotemporal brain disorder their unusual behaviour can often be misunderstood, including if charged with a criminal offence.
Executive functions are a complex set of cognitive processes which are mediated by the frontal lobes and their associated tracts. They have been defined as “a collection of processes that are responsible for guiding, directing, and managing cognitive, emotional, and behavioural functions, particularly during active, novel problem solving”.
There are different forms of frontotemporal degeneration, one of those is behavioural variant frontotemporal dementia (bvFTD). People with bvFTD often have trouble controlling their behaviour, saying inappropriate things and ignoring people’s feelings.
An investigation in 2015 examined the emergence of antisocial and criminal behaviour for the first time in older adults which found patients with bvFTD were more likely to present with criminal behaviour. Disorders affecting the frontotemporal or fronto-subcortical circuits were particularly associated with first time offending in older adults, particularly bvFTD, semantic variant primary progressive aphasia and Huntington’s disease.
Common criminal behaviour in the bvFTD group included theft, traffic violations, sexual advances, trespassing, and public urination in contrast with those in the Alzheimer disease group, who commonly committed traffic violations, often related to cognitive impairment.
There is also an emerging body of academic literature regarding elderly aged adult first-time sex offenders, and the development of a neurodegenerative disorder and deterioration of cognitive processes may be associated with first time sex offending.
An Australian study specifically investigated whether first-time older adult sex-offenders differed from historical long-term sex offenders and non-sex offenders. Older adult sex-offenders (both historic and first-time offenders) performed more poorly on tests of executive functions than the non-sex offending control group. Specifically, they performed worse on tests of response inhibition, verbal fluency and response alternation which was consistent with orbitofrontal dysfunction. There were also deficits in visual and verbal memory.
The authors observed that these deficits were consistent with those found in frontotemporal dementia, and they raised the possibility that a proportion of first-time sex offenders may have frontotemporal dementia. They concluded that damage to the frontal / executive system later in life, including due to cardiovascular disease, could contribute to sexual offending.
These population groups are challenging from the perspective of the Courts in terms of their competency to commit the offence, as they can often appreciate right and wrong, but due to the cognitive and behavioural changes associated with their neurodegenerative disorder, they are unable to act accordingly or inhibit their impulses.
It is essential if you or someone you know has been charged with a criminal offence, and there is a chance they are experiencing cognitive and behavioural changes, you contact Hugo Law Group to obtain representation from an experienced criminal defence lawyer that can identify these issues and have them appropriately investigated. In the appropriate case it will be essential to brief an appropriately qualified expert.
Tom Taylor, Partner
 Gioia, G. A., Isquith, P. K., Guy, S. C., & Kenworthy, L. (2000). BRIEF: Behaviour Rating Inventory of Executive Function Professional Manual. Lutz, FL: PAR.
 Liljegren, M., Naasan, G., Temlett, J., Perry, D., Rankin, K. P., Merrilees, J., Grinberg, L. T., Seeley, W. W. Englund, E., & Miller, B. (2015). Criminal Behavior in Frontotemporal Dementia and Alzheimer Disease. JAMA Neurology, 72, 295-300.
 Eastvold, A., Suchy, Y., & Strassberg, D. (2011). Executive Function Profiles of Pedophilic and Nonpedophilic Child Molesters. Journal of the International Neuropsychological Society,17, 295-307. Adjorlolo, S., Egbenya, D. L. (2016). Executive functioning profiles of adult and juvenile male sexual offenders: A systematic review. The Journal of Forensic Psychiatry & Psychology, 27, 349-375.
 Rodriguez, M., Boyce, P., & Hodges, J. (2017). A neuropsychological study of older adult first-time 4 sex offenders. Neurocase, 23, 154-161.