RESUMEN
BACKGROUND: Neuroimaging studies examining neural substrates of impaired self-awareness in patients with neurodegenerative diseases have shown divergent results depending on the modality (cognitive, emotional, behavioral) of awareness. Evidence is accumulating to suggest that self-awareness arises from a combination of modality-specific and large-scale supramodal neural networks. METHODS: We investigated the structural substrates of patients' tendency to overestimate or underestimate their own capacity to demonstrate empathic concern for others. Subjects' level of empathic concern was measured using the Interpersonal Reactivity Index, and subject-informant discrepancy scores were used to predict regional atrophy pattern, using voxel-based morphometry analysis. Of the 102 subjects, 83 were patients with neurodegenerative diseases such as behavioral variant frontotemporal dementia (bvFTD) or semantic variant primary progressive aphasia (svPPA); the other 19 were healthy older adults. RESULTS: bvFTD and svPPA patients typically overestimated their level of empathic concern compared to controls, and overestimating one's empathic concern predicted damage to predominantly right-hemispheric anterior infero-lateral temporal regions, whereas underestimating one's empathic concern showed no neuroanatomical basis. CONCLUSIONS: These findings suggest that overestimation and underestimation of one's capacity for empathic concern cannot be interpreted as varying degrees of the same phenomenon, but may arise from different pathophysiological processes. Damage to anterior infero-lateral temporal regions has been associated with semantic self-knowledge, emotion processing, and social perspective taking; neuropsychological functions partly associated with empathic concern itself. These findings support the hypothesis that-at least in the socioemotional domain-neural substrates of self-awareness are partly modality-specific.
Asunto(s)
Concienciación/fisiología , Empatía/fisiología , Degeneración Lobar Frontotemporal/patología , Degeneración Lobar Frontotemporal/fisiopatología , Autoevaluación (Psicología) , Lóbulo Temporal/patología , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: Memantine has been used off-label to treat frontotemporal lobar degeneration (FTD). A previous 26-week open-label study suggested a transient, modest benefit on neuropsychiatric symptoms as measured by the neuropsychiatric inventory (NPI). We aimed to determine whether memantine is an effective treatment for FTD. METHODS: We did a randomised, parallel group, double-blind, placebo-controlled trial of 20 mg memantine taken orally daily for 26 weeks in patients with FTD. Participants met Neary criteria for behavioural variant FTD (bvFTD) or semantic dementia and had characteristic brain atrophy. Use of acetylcholinesterase inhibitors was prohibited. Individuals were randomly assigned to receive either memantine or matched placebo tablets (1:1) in blocks of two and four patients. All patients and study personnel were masked to treatment assignment. Primary endpoints were the change in total NPI score and clinical global impression of change (CGIC) score after 26 weeks and were analysed by intention to treat. This study is registered with Clinicaltrials.gov, number NCT00545974. FINDINGS: Of 100 patients screened, 81 were randomly assigned to receive memantine (39 patients) or placebo (42 patients). Five (6%) patients discontinued, and 76 completed the 26-week treatment. Enrolment numbers were lower than planned because of many patients' preference to take memantine or cholinesterase inhibitors off-label rather than participate in a clinical trial. Memantine treatment had no effect on either the NPI (mean difference 2·2, 95% CI -3·9 to 8·3, p=0·47) or CGIC (mean difference 0·0, -0·4 to 0·4, p=0·90) after 26 weeks of treatment. Memantine was generally well tolerated; however, patients in the memantine group had more frequent cognitive adverse events (six patients) than those in the placebo group (one). INTERPRETATION: Memantine treatment showed no benefit in patients with FTD. These data do not support memantine use in FTD. FUNDING: Forest Research Institute.