The Importance of the Exceptional in Tackling Riddles of Consciousness and Unusual Episodes of Lucidity

Abstract

The problem of how biochemical processes in the brain give rise to conscious experience is still unanswered. This paper aims at stimulating the debate surrounding this enigma by advocating the study of unusual and anomalous aspects of consciousness. For this purpose, the contents of this paper are organized in three parts. In the first part, I provide a brief overview on unsolved riddles of the mind. These include unusual episodes of lucidity that have been termed terminal lucidity and paradoxical lucidity. Because the use of these terms has sometimes been inappropriate in recent literature, I clarify the basic meanings of these two concepts in the second part. The third part contains suggestions for future research. Specifically, I argue that the field of studies into episodes of lucidity in dementias and the field of studies into end-of-life experiences, such as near-death visions, should engage in an active dialogue in order to build bridges between these disciplines. Such a dialogue will enable a better understanding of the whole spectrum, and thus, possible circumstances, causes and underpinnings of lucid episodes. In sum, this paper argues that the study of lucid episodes such as terminal lucidity, paradoxical lucidity, and related occurrences holds enormous significance for improving our understanding of brain functions and accompanying states of consciousness – from a practice-orientated perspective in the contexts of the dementias and dealing with end-of-life experiences, and from a theoretical perspective in the context of the scientific debate about the nature of consciousness.

The Impact of Episodes of Lucidity on People Living With Dementia and Their Caregivers

“…More recently, attention has been paid to the importance of clarifying the meaning and definition of lucid episodes that are paradoxical, which implies the presence of an irreversible neurodegenerative brain condition that is inconsistent with observed mental lucidity. 12 In addition, a preliminary research framework for investigating lucidity in dementia broadly states that restricting inquiry into lucidity to "remarkable" and "spontaneous" events in advanced dementia may prematurely narrow the definitional scope of what is and what is not an EL. 5 A more general definition for EL was provided by Norman and colleagues, who define an EL as an episode where the person seems to be more aware of their situation and functions more adequately than usual, which is surprising to observers.…”

“…As there is currently no universally accepted definition for ELs, there is an ongoing discussion about the defining characteristics that constitute an EL 5. Multiple definitions have been presented in published literature, and the distinction between paradoxical and/or terminal lucid episodes in particular, is an active area of discussion 12. A widely circulated definition from the National Institute on Aging Workshop on Lucidity in Dementia highlights paradoxical lucidity as “unexpected, spontaneous, meaningful, and relevant communication or connectedness in a patient who is assumed to have permanently lost the capacity for coherent verbal or behavioral interaction due to a progressive and pathophysiologic dementing process.”1 Peterson et al4 critically analyzed this definition’s criterion of spontaneity, meaningful and relevant, and communication and connectedness, arguing that these various criteria require further study and clarification.…”

“…A widely circulated definition from the National Institute on Aging Workshop on Lucidity in Dementia highlights paradoxical lucidity as “unexpected, spontaneous, meaningful, and relevant communication or connectedness in a patient who is assumed to have permanently lost the capacity for coherent verbal or behavioral interaction due to a progressive and pathophysiologic dementing process.”1 Peterson et al4 critically analyzed this definition’s criterion of spontaneity, meaningful and relevant, and communication and connectedness, arguing that these various criteria require further study and clarification. More recently, attention has been paid to the importance of clarifying the meaning and definition of lucid episodes that are paradoxical, which implies the presence of an irreversible neurodegenerative brain condition that is inconsistent with observed mental lucidity 12. In addition, a preliminary research framework for investigating lucidity in dementia broadly states that restricting inquiry into lucidity to “remarkable” and “spontaneous” events in advanced dementia may prematurely narrow the definitional scope of what is and what is not an EL 5.…”

Developing and describing a typology of lucid episodes among people with Alzheimer's disease and related dementias

“…Some people with late‐stage Alzheimer's disease and related dementias (ADRD) have been reported, largely by way of anecdote and case studies, 1,2 to exhibit unexpected episodes of spontaneous, meaningful, and relevant communication or behavior. These lucid episodes (LEs), sometimes referred to as paradoxical lucidity because of their inconsistency with current models of the pathophysiology of ADRD 3 and lack of scientific explanation, are characterized by periods of mental clarity in persons living with ADRD (PLWD) who are assumed to have lost coherent cognitive capacity. LEs in PLWD have frequently been overlooked and have received relatively little research or clinical attention, 2,3 but case reports have provided useful initial insights into their dimensions, especially those that occur at the end of life 4,5 .…”

“…These lucid episodes (LEs), sometimes referred to as paradoxical lucidity because of their inconsistency with current models of the pathophysiology of ADRD 3 and lack of scientific explanation, are characterized by periods of mental clarity in persons living with ADRD (PLWD) who are assumed to have lost coherent cognitive capacity. LEs in PLWD have frequently been overlooked and have received relatively little research or clinical attention, 2,3 but case reports have provided useful initial insights into their dimensions, especially those that occur at the end of life 4,5 . To date, there is little agreement on precise definitions of what an LE is and is not 6–8 .…”