Distorted temporal consciousness and preserved knowing consciousness in confabulation: a case study

In this study we describe a patient, TA, who developed a chronic amnesic-confabulatory syndrome, following rupture of a right internal carotid siphon aneurysm. Our aim was to elucidate as fully as possible the nature of TA's impairment and to test the hypothesis of confabulation as reflecting a dysfunction of Temporal Consciousness, i.e., to become aware of something as part of a personal past, present or future. TA's confabulations were present in answers to questions tapping Temporal Consciousness, i.e., autobiographical episodic memory, orientation in time and place, and foresight of personal future. In contrast, confabulations were not observed in answers to questions tapping Knowing Consciousness, i.e., to become aware of something as a meaning or as an element of impersonal knowledge. In fact, he had normal access to semantic knowledge, including foresight of impersonal future. TA's brain MRI showed lesions involving the right hippocampus, parahippocampal gyrus, fornix, mammillary bodies, and thalamus. Moreover TA showed sub-cortical lesions involving the caudate and putamen nuclei bilaterally, a lesion site not commonly described in amnesic-confabulatory syndrome. We suggest that this pattern of results is better accounted for within the framework of the Memory, Consciousness and Temporality Theory and reflects a specific distortion of Temporal Consciousness.