Clinical Assessment of Prefrontal Lobe Functions

Alexandre Henri-Bhargava, MDCM, MScCH, FRCPC; Donald T. Stuss, OC, O Ont, PhD, FRSC, FCAHS, CPsych, ABPP-CN; Morris Freedman, MD, FRCPC, FAAN Behavioral Neurology and Psychiatry p. 704-726 June 2018, Vol.24, No.3 doi: 10.1212/CON.0000000000000609
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PURPOSE OF REVIEW Whereas it was previously thought that there was a single overarching frontal lobe syndrome, it is now clear that several distinct cognitive and behavioral processes are mediated by the frontal lobes. This article reviews these processes and the underlying neuroanatomy and provides an approach to the assessment of prefrontal lobe functions at the bedside.

RECENT FINDINGS Cognitive and behavioral frontal lobe functions are mediated by the prefrontal regions rather than the frontal lobes as a whole. At least five separate prefrontal functions have been defined: energization, task setting, monitoring, behavioral/emotional regulation, and metacognition. Energization is mediated by the superior medial prefrontal cortices bilaterally, task setting by the left lateral frontal cortex, monitoring by the right lateral prefrontal cortex, behavioral/emotional regulation by the orbitofrontal cortex, and metacognition by the frontal poles. Only task setting and monitoring are considered executive functions.

SUMMARY Distinct cognitive and behavioral processes are mediated by different parts of the frontal lobe. Lesions in these areas result in characteristic clinical deficits that are discussed in this article. Key messages are that prefrontal regions mediate the higher cortical functions (as opposed to the frontal lobes in general) and that prefrontal functions are not equivalent to executive functions.

Address correspondence to Dr Alexandre Henri-Bhargava, Island Medical Program, University of Victoria, PO Box 1700 STN CSC, Victoria, BC V8W 2Y2, Canada,

RELATIONSHIP DISCLOSURE: Dr Henri-Bhargava has received funding for clinical trials from AstraZeneca, Boehringer Ingelheim Ltd, Eli Lilly and Company, F. Hoffman-La Roche Ltd, and TauRx and has provided expert legal testimony in personal injury litigation in British Columbia. Dr Stuss serves on the advisory board of Spindle Strategy Corporation and has received personal compensation for speaking engagements for Bennett Jones LLP. Dr Stuss receives publishing royalties from Cambridge University Press. Dr Freedman serves as a trustee for the World Federation of Neurology and on the editorial boards of Brain and Cognition and Journal of Parapsychology; has received support from and served on an advisory board for Eli Lilly and Company Canada and receives publishing royalties from Oxford University Press; receives research/grant support from the Alzheimer Society of Canada, Brain Canada Foundation, Centre for Aging and Brain Health Innovation, Canadian Institutes of Health Research, and Westin Brain Institute; receives support from the Behavioural Neurology Physician Recognition Covenant Fund at Baycrest, the Morris Kerzner Memorial Fund, and the Saul A. Silverman Foundation as part of the Canada International Scientific Exchange Program project; and holds stock in companies producing or planning to produce medical marijuana and is listed on a provisional patent related to methods and kits for differential diagnosis of Alzheimer disease.

UNLABELED USE OF PRODUCTS/INVESTIGATIONAL USE DISCLOSURE: Drs Henri-Bhargava, Stuss, and Freedman report no disclosures.


© 2018 American Academy of Neurology.