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Nondominant Frontal Function Is Linked to the Concept of Self

Over the past several years, clinicians and neuroscientists have begun to investigate the human mental processes that are most remote from sensory and motor functions: character, consciousness, empathy, deceit, humor, and self-awareness. These terms, previously the domain of theologians and philosophers, sometimes make scientists uncomfortable. These investigators conducted a retrospective analysis of patients with frontotemporal dementia (FTD) to determine whether clinical analysis can illuminate these darker crevasses of neurologic function.

Case records of 72 patients with diagnoses of FTD by the Lund-Manchester consensus criteria were reviewed by two independent teams. One inspected only MRI and SPECT to separate patients with predominantly right frontal atrophy from those with all other patterns of atrophy, including bifrontal atrophy. The other, blinded to imaging results, inspected medical records to identify patients who showed a change in "core aspects of self" -- using, as have all others investigating similar phenomena, the definitions of William James. Seven patients had atrophy predominantly affecting the nondominant frontal lobe; 6 of the 7 had a "change in self" compared with only 1 of 65 patients with another pattern of atrophy (P < 0.001). The authors conclude that integrity of right frontal structures is critical to maintenance of a stable concept of self.

Comment: Self, however defined, is extraordinarily difficult to investigate in a clinical population, and retrospective studies are notoriously prone to bias unless the data to be extracted are absolutely objective. This study must have been particularly difficult to manage. SPECT, rather than MRI, appears to have been the critical measure of atrophy, so anatomic descriptions are quite coarse-grained; for example, atrophy of the amygdala is not mentioned, even in the 3 patients who eventually had autopsies. The timing of the SPECT study in relation to the clinical course is not revealed. Could the "medical records" really have had no mention of imaging studies used to reach the original diagnosis of FTD? It is unclear how many people participated in the clinical review and how the core aspects of self were enumerated. There is no information about executive cognitive impairments at the time of "change in self." For all of its limitations, however, the current report is commendable and encouraging. The 7 clinical vignettes are quite compelling, and given the encompassing definition of self that the authors chose (albeit from a college dictionary), the case is made that these patients had a disorder of self. Their old selves had changed -- deteriorated in each case.

In another era or from a different perspective, these compelling histories might have been cited as examples of impairments in comportment, social regulation, utilization of humor, inhibition of drives, emotional modulation, or theory of mind. The behaviors might have been described as stereotyped, disinhibited, inappropriate, or anosognosic. The present difficulty is not that these complex personal and social behaviors don't constitute a valid and exciting realm of study -- it is that our models of the cognitive and affective architecture that will support their study are so incompletely developed. We are left with an evocative abstract vocabulary -- self, consciousness, comportment -- but precious little concrete methodology to investigate it. Cognitive scientists such as Tim Shallice and Myrna Schwartz have developed specific and testable models for complex, unstructured actions. Similar approaches to consciousness and self are emerging from a collective awareness that these are topics too important to be spurned as untestable any longer.

— MP Alexander

Michael P. Alexander, MD, is Associate Clinical Professor of Neurology, Departments of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.

Published in Journal Watch Neurology October 25, 2001

Citation(s):

Miller BL et al. Neuroanatomy of the self: Evidence from patients with frontotemporal dementia. Neurology 2001 Sep 11 57 817-821.

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