RESUMEN
BACKGROUND: Patients with brain injury who are unresponsive to commands may perform cognitive tasks that are detected on functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). This phenomenon, known as cognitive motor dissociation, has not been systematically studied in a large cohort of persons with disorders of consciousness. METHODS: In this prospective cohort study conducted at six international centers, we collected clinical, behavioral, and task-based fMRI and EEG data from a convenience sample of 353 adults with disorders of consciousness. We assessed the response to commands on task-based fMRI or EEG in participants without an observable response to verbal commands (i.e., those with a behavioral diagnosis of coma, vegetative state, or minimally conscious state-minus) and in participants with an observable response to verbal commands. The presence or absence of an observable response to commands was assessed with the use of the Coma Recovery Scale-Revised (CRS-R). RESULTS: Data from fMRI only or EEG only were available for 65% of the participants, and data from both fMRI and EEG were available for 35%. The median age of the participants was 37.9 years, the median time between brain injury and assessment with the CRS-R was 7.9 months (25% of the participants were assessed with the CRS-R within 28 days after injury), and brain trauma was an etiologic factor in 50%. We detected cognitive motor dissociation in 60 of the 241 participants (25%) without an observable response to commands, of whom 11 had been assessed with the use of fMRI only, 13 with the use of EEG only, and 36 with the use of both techniques. Cognitive motor dissociation was associated with younger age, longer time since injury, and brain trauma as an etiologic factor. In contrast, responses on task-based fMRI or EEG occurred in 43 of 112 participants (38%) with an observable response to verbal commands. CONCLUSIONS: Approximately one in four participants without an observable response to commands performed a cognitive task on fMRI or EEG as compared with one in three participants with an observable response to commands. (Funded by the James S. McDonnell Foundation and others.).
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Lesiones Encefálicas , Trastornos de la Conciencia , Trastornos Disociativos , Estado Vegetativo Persistente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Lesiones Encefálicas/fisiopatología , Lesiones Encefálicas/complicaciones , Lesiones Encefálicas/diagnóstico por imagen , Cognición/fisiología , Trastornos de la Conciencia/diagnóstico por imagen , Trastornos de la Conciencia/etiología , Trastornos de la Conciencia/fisiopatología , Electroencefalografía , Imagen por Resonancia Magnética , Estado Vegetativo Persistente/diagnóstico por imagen , Estado Vegetativo Persistente/etiología , Estado Vegetativo Persistente/fisiopatología , Estudios Prospectivos , Trastornos Disociativos/diagnóstico por imagen , Trastornos Disociativos/etiología , Trastornos Disociativos/fisiopatologíaRESUMEN
Recent advancements in functional neuroimaging have demonstrated that some unresponsive patients in the intensive care unit retain a level of consciousness that is inconsistent with their behavioral diagnosis of awareness. Functional near-infrared spectroscopy (fNIRS) is a portable optical neuroimaging method that can be used to measure neural activity with good temporal and spatial resolution. However, the reliability of fNIRS for detecting the neural correlates of consciousness remains to be established. In a series of studies, we evaluated whether fNIRS can record sensory, perceptual, and command-driven neural processing in healthy participants and in behaviorally nonresponsive patients. At the individual healthy subject level, we demonstrate that fNIRS can detect commonly studied resting state networks, sensorimotor processing, speech-specific auditory processing, and volitional command-driven brain activity to a motor imagery task. We then tested fNIRS with three acutely brain injured patients and found that one could willfully modulate their brain activity when instructed to imagine playing a game of tennis-providing evidence of preserved consciousness despite no observable behavioral signs of awareness. The successful application of fNIRS for detecting preserved awareness among behaviorally nonresponsive patients highlights its potential as a valuable tool for uncovering hidden cognitive states in critical care settings.
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Lesiones Encefálicas , Estado de Conciencia , Espectroscopía Infrarroja Corta , Humanos , Espectroscopía Infrarroja Corta/métodos , Estado de Conciencia/fisiología , Masculino , Adulto , Femenino , Lesiones Encefálicas/fisiopatología , Lesiones Encefálicas/diagnóstico por imagen , Encéfalo/fisiopatología , Encéfalo/diagnóstico por imagen , Persona de Mediana Edad , Neuroimagen Funcional/métodos , Adulto JovenRESUMEN
Humor comprehension (i.e., getting a joke) and humor appreciation (i.e., enjoying a joke) are distinct, cognitively complex processes. Functional magnetic resonance imaging (fMRI) investigations have identified several key cortical regions but have overlooked subcortical structures that have theoretical importance in humor processing. The dorsal striatum (DS) contributes to working memory, ambiguity processing, and cognitive flexibility, cognitive functions that are required to accurately recognize humorous stimuli. The ventral striatum (VS) is critical in reward processing and enjoyment. We hypothesized that the DS and VS play important roles in humor comprehension and appreciation, respectively. We investigated the engagement of these regions in these distinct processes using fMRI. Twenty-six healthy young male and female human adults completed two humor-elicitation tasks during a 3 tesla fMRI scan consisting of a traditional behavior-based joke task and a naturalistic audiovisual sitcom paradigm (i.e., Seinfeld viewing task). Across both humor-elicitation methods, whole-brain analyses revealed cortical activation in the inferior frontal gyrus, the middle frontal gyrus, and the middle temporal gyrus for humor comprehension, and the temporal cortex for humor appreciation. Additionally, with region of interest analyses, we specifically examined whether DS and VS activation correlated with these processes. Across both tasks, we demonstrated that humor comprehension implicates both the DS and the VS, whereas humor appreciation only engages the VS. These results establish the role of the DS in humor comprehension, which has been previously overlooked, and emphasize the role of the VS in humor processing more generally.SIGNIFICANCE STATEMENT Humorous stimuli are processed by the brain in at least two distinct stages. First, humor comprehension involves understanding humorous intent through cognitive and problem-solving mechanisms. Second, humor appreciation involves enjoyment, mirth, and laughter in response to a joke. The roles of smaller subcortical brain regions in humor processing, such as the DS and VS, have been overlooked in previous investigations. However, these regions are involved in functions that support humor comprehension (e.g., working memory ambiguity resolution, and cognitive flexibility) and humor appreciation (e.g., reward processing, pleasure, and enjoyment). In this study, we used neuroimaging to demonstrate that the DS and VS play important roles in humor comprehension and appreciation, respectively, across two different humor-elicitation tasks.
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Comprensión , Imagen por Resonancia Magnética , Adulto , Humanos , Masculino , Femenino , Comprensión/fisiología , Imagen por Resonancia Magnética/métodos , Encéfalo/fisiología , Lóbulo Temporal/fisiología , Lóbulo Frontal/fisiología , Mapeo EncefálicoRESUMEN
OBJECTIVE: Little is known about residual cognitive function in the earliest stages of serious brain injury. Functional neuroimaging has yielded valuable diagnostic and prognostic information in chronic disorders of consciousness, such as the vegetative state (also termed unresponsive wakefulness syndrome). The objective of the current study was to determine if functional neuroimaging could be efficacious in the assessment of cognitive function in acute disorders of consciousness, such as coma, where decisions about the withdrawal of life-sustaining therapies are often made. METHODS: A hierarchical functional magnetic resonance imaging (fMRI) approach assessed sound perception, speech perception, language comprehension, and covert command following in 17 critically ill patients admitted to the intensive care unit (ICU). RESULTS: Preserved auditory function was observed in 15 patients (88%), whereas 5 (29%) also had preserved higher-order language comprehension. Notably, one patient could willfully modulate his brain activity when instructed to do so, suggesting a level of covert conscious awareness that was entirely inconsistent with his clinical diagnosis at the time of the scan. Across patients, a positive relationship was also observed between fMRI responsivity and the level of functional recovery, such that patients with the greatest functional recovery had neural responses most similar to those observed in healthy control participants. INTERPRETATION: These results suggest that fMRI may provide important diagnostic and prognostic information beyond standard clinical assessment in acutely unresponsive patients, which may aid discussions surrounding the continuation or removal of life-sustaining therapies during the early post-injury period. ANN NEUROL 2023;93:131-141.
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Lesiones Encefálicas , Trastornos de la Conciencia , Humanos , Trastornos de la Conciencia/diagnóstico , Enfermedad Crítica , Encéfalo/diagnóstico por imagen , Lesiones Encefálicas/diagnóstico por imagen , Estado Vegetativo Persistente/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Neuroimagen Funcional , NeuroimagenRESUMEN
Sleep spindles (SP) are one of the few known electrophysiological neuronal biomarkers of interindividual differences in cognitive abilities and aptitudes. Recent simultaneous electroencephalography with functional magnetic resonance imaging (EEG-fMRI) studies suggest that the magnitude of the activation of brain regions recruited during spontaneous spindle events is specifically related to Reasoning abilities. However, it is not known if the relationship with cognitive abilities differs between uncoupled spindles, uncoupled slow waves (SW), and coupled SW-SP complexes, nor have the functional-neuroanatomical substrates that support this relationship been identified. Here, we investigated the functional significance of activation of brain areas recruited during SW-coupled spindles, uncoupled spindles, and uncoupled slow waves. We hypothesize that brain activations time locked to SW-coupled spindle complexes will be primarily associated to Reasoning abilities, especially in subcortical areas. Our results provide direct evidence that the relationship between Reasoning abilities and sleep spindles depends on spindle coupling status. Specifically, we found that the putamen and thalamus, recruited during coupled SW-SP events were positively correlated with Reasoning abilities. In addition, we found a negative association between Reasoning abilities and hippocampal activation time-locked to uncoupled SWs that might reflect a refractory mechanism in the absence of new, intensive hippocampal-dependent memory processing.
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Sueño de Onda Lenta , Sueño/fisiología , Electroencefalografía/métodos , Cognición , Encéfalo/fisiologíaRESUMEN
In the human electroencephalogram (EEG), oscillatory power co-exist with non-oscillatory, aperiodic activity. Although EEG analysis has traditionally focused exclusively on oscillatory power, recent investigations have shown that the aperiodic EEG component can distinguish conscious wakefulness from sleep and anesthetic-induced unconsciousness. This study investigates the aperiodic EEG component of individuals in a disorder of consciousness (DOC); how it changes in response to exposure to anesthesia; and how it relates to the brain's information richness and criticality. High-density EEG was recorded from 43 individuals in a DOC, with 16 of these individuals undergoing a protocol of propofol anesthesia. The aperiodic component was defined by the spectral slope of the power spectral density. Our results demonstrate that the EEG aperiodic component is more informative about the participants' level of consciousness than the oscillatory component, especially for patients that suffered from a stroke. Importantly, the pharmacologically induced change in the spectral slope from 30 to 45 Hz positively correlated with individual's pre-anesthetic level of consciousness. The pharmacologically induced loss of information-richness and criticality was associated with individual's pre-anesthetic aperiodic component. During exposure to anesthesia, the aperiodic component distinguished individuals with DOC, according to their 3-month recovery status. The aperiodic EEG component has been historically neglected; this research highlights the necessity of considering this measure for the assessment of individuals in DOC and future research that seeks to understand the neurophysiological underpinnings of consciousness.
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Anestesia , Anestésicos , Humanos , Estado de Conciencia/fisiología , Trastornos de la Conciencia/inducido químicamente , Electroencefalografía , Encéfalo/fisiologíaRESUMEN
Anaesthesia combined with functional neuroimaging provides a powerful approach for understanding the brain mechanisms of consciousness. Although propofol is used ubiquitously in clinical interventions that reversibly suppress consciousness, it shows large inter-individual variability, and the brain bases of this variability remain poorly understood. We asked whether three networks key to conscious cognition-the dorsal attention (DAN), executive control (ECN), and default mode (DMN)-underlie responsiveness variability under anaesthesia. Healthy participants (N = 17) were moderately anaesthetized during narrative understanding and resting-state conditions inside the Magnetic Resonance Imaging scanner. A target detection task measured behavioural responsiveness. An independent behavioural study (N = 25) qualified the attention demands of narrative understanding. Then, 30% of participants were unaffected in their response times, thus thwarting a key aim of anaesthesia-the suppression of behavioural responsiveness. Individuals with stronger functional connectivity within the DAN and ECN, between them, and to the DMN, and with larger grey matter volume in frontal regions were more resilient to anaesthesia. For the first time, we show that responsiveness variability during propofol anaesthesia relates to inherent differences in brain structure and function of the frontoparietal networks, which can be predicted prior to sedation. Results highlight novel markers for improving awareness monitoring during clinical anaesthesia.
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Anestesia , Propofol , Humanos , Propofol/farmacología , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Estado de Conciencia/fisiología , Cognición , Mapeo Encefálico , Imagen por Resonancia Magnética/métodos , Vías Nerviosas/diagnóstico por imagen , Función EjecutivaRESUMEN
BACKGROUND: Sedation of critically ill patients with inhaled anaesthetics may reduce lung inflammation, time to extubation, and ICU length of stay compared with intravenous (i.v.) sedatives. However, the impact of inhaled anaesthetics on cognitive and psychiatric outcomes in this population is unclear. In this systematic review, we aimed to summarise the effect of inhaled anaesthetics on cognitive and psychiatric outcomes in critically ill adults. METHODS: We searched MEDLINE, EMBASE, and PsycINFO for case series, retrospective, and prospective studies in critically ill adults sedated with inhaled anaesthetics. Outcomes included delirium, psychomotor and neurological recovery, long-term cognitive dysfunction, ICU memories, anxiety, depression, post-traumatic stress disorder (PTSD), and instruments used for assessment. RESULTS: Thirteen studies were included in distinct populations of post-cardiac arrest survivors (n=4), postoperative noncardiac patients (n=3), postoperative cardiac patients (n=2), and mixed medical-surgical patients (n=4). Eight studies reported delirium incidence, two neurological recovery, and two ICU memories. One study reported on psychomotor recovery, long-term cognitive dysfunction, anxiety, depression, and PTSD. A meta-analysis of five trials found no difference in delirium incidence between inhaled and i.v. sedatives (relative risk 0.95 [95% confidence interval: 0.59-1.54]). Compared with i.v. sedatives, inhaled anaesthetics were associated with fewer hallucinations and faster psychomotor recovery but no differences in other outcomes. There was heterogeneity in the instruments used and timing of these assessments. CONCLUSIONS: Based on the limited evidence available, there is no difference in cognitive and psychiatric outcomes between adults exposed to volatile sedation or intravenous sedation in the ICU. Future studies should incorporate outcome assessment with validated tools during and after hospital stay. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42021236455.
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Anestésicos , Delirio , Humanos , Adulto , Enfermedad Crítica , Estudios Prospectivos , Estudios Retrospectivos , Hipnóticos y Sedantes , Cognición , Unidades de Cuidados IntensivosRESUMEN
Rationale: Predicting recovery of consciousness in unresponsive, brain-injured individuals has crucial implications for clinical decision-making. Propofol induces distinctive brain network reconfiguration in the healthy brain as it loses consciousness. In patients with disorders of consciousness, the brain network's reconfiguration to propofol may reveal the patient's underlying capacity for consciousness. Objectives: To design and test a new metric for the prognostication of consciousness recovery in disorders of consciousness. Methods: Using a within-subject design, we conducted an anesthetic protocol with concomitant high-density EEG in 12 patients with a disorder of consciousness after a brain injury. We quantified the reconfiguration of EEG network hubs and directed functional connectivity before, during, and after propofol exposure and obtained an index of propofol-induced network reconfiguration: the adaptive reconfiguration index. We compared the index of patients who recovered consciousness 3 months after EEG (n = 3) to that of patients who did not recover or remained in a chronic disorder of consciousness (n = 7) and conducted a logistic regression to assess prognostic accuracy. Measurements and Main Results: The adaptive reconfiguration index was significantly higher in patients who later recovered full consciousness (U value = 21, P = 0.008) and able to discriminate with 100% accuracy whether the patient recovered consciousness. Conclusions: The adaptive reconfiguration index of patients who recovered from a disorder of consciousness at 3-month follow-up was linearly separable from that of patients who did not recover or remained in a chronic disorder of consciousness on the single-subject level. EEG and propofol can be administered at the bedside with few contraindications, affording the adaptive reconfiguration index tremendous translational potential as a prognostic measure of consciousness recovery in acute clinical settings.
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Lesiones Encefálicas/inducido químicamente , Lesiones Encefálicas/fisiopatología , Coma/inducido químicamente , Coma/fisiopatología , Trastornos de la Conciencia/inducido químicamente , Trastornos de la Conciencia/fisiopatología , Estado de Conciencia/efectos de los fármacos , Propofol/efectos adversos , Adolescente , Adulto , Anciano , Periodo de Recuperación de la Anestesia , Femenino , Predicción , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Recuperación de la Función/efectos de los fármacos , Adulto JovenRESUMEN
Small world topologies are thought to provide a valuable insight into human brain organisation and consciousness. However, functional magnetic resonance imaging studies in consciousness have not yielded consistent results. Given the importance of dynamics for both consciousness and cognition, here we investigate how the diversity of small world dynamics (quantified by sample entropy; dSW-E1) scales with decreasing levels of awareness (i.e., sedation and disorders of consciousness). Paying particular attention to result reproducibility, we show that dSW-E is a consistent predictor of levels of awareness even when controlling for the underlying functional connectivity dynamics. We find that dSW-E of subcortical, and cortical areas are predictive, with the former showing higher and more robust effect sizes across analyses. We find that the network dynamics of intermodular communication in the cerebellum also have unique predictive power for levels of awareness. Consequently, we propose that the dynamic reorganisation of the functional information architecture, in particular of the subcortex, is a characteristic that emerges with awareness and has explanatory power beyond that of the complexity of dynamic functional connectivity.
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Estado de Conciencia , Red Nerviosa , Encéfalo , Humanos , Imagen por Resonancia Magnética , Red Nerviosa/diagnóstico por imagen , Reproducibilidad de los ResultadosRESUMEN
In the last few years, functional neuroimaging and electroencephalography-based techniques have been used to address one of the most complex and challenging questions in clinical medicine, that of detecting covert awareness in behaviorally unresponsive patients who have survived severe brain injuries. This is a very diverse population with a wide range of etiologies and comorbidities, as well as variable cognitive and behavioral abilities, which render accurate diagnosis extremely challenging. These studies have shown that some chronic behaviorally unresponsive patients harbor not only covert consciousness but also highly preserved levels of mental life. Building on this work, although in its infancy, the investigation of covert consciousness in acutely brain-injured patients could have profound implications for patient prognosis, treatment, and decisions regarding withdrawal of care. The body of evidence on covert awareness presents a moral imperative to redouble our efforts for improving the quality of life and standard of care for all brain-injured patients with disorders of consciousness.
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Lesiones Encefálicas , Estado de Conciencia , Encéfalo , Lesiones Encefálicas/diagnóstico , Lesiones Encefálicas/terapia , Trastornos de la Conciencia/diagnóstico , Trastornos de la Conciencia/terapia , Humanos , Calidad de VidaRESUMEN
In March 2020, the Royal College of Physicians in the UK published national guidelines on the management of patients with prolonged disorders of consciousness, updating their 2013 guidance 'particularly in relation to recent developments in assessment and management and changes in the law governing the withdrawal of clinically assisted nutrition and hydration'. The report's primary focus is on patients who could live for many years with treatment and care. This update, by a neurologist, an imaging neuroscientist, and a lawyer-ethicist, questions the document's rejection of any significant role for neuroimaging techniques including functional MRI and/or bedside EEG to detect covert consciousness in such patients. We find the reasons for this rejection unconvincing, given (i) the significant advances made in the use of this technology in recent years; and (ii) the wider scope for its use envisaged by the earlier (2018) guidelines issued by the American Academy of Neurology. We suggest that, since around one in five patients diagnosed with prolonged disorders of consciousness are in fact conscious enough to follow commands in a neuroimaging context (i.e. those who are 'covertly conscious' or those with 'cognitive motor dissociation'), and given the clinical, ethical and legal importance of determining whether patients with prolonged disorders of consciousness are legally competent or at least able to express their views and feelings, the guidance from the Royal College of Physicians requires urgent review.
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Trastornos de la Conciencia/diagnóstico por imagen , Neuroimagen/métodos , Humanos , Guías de Práctica Clínica como Asunto , Reino UnidoRESUMEN
Humans can mentally represent auditory information without an external stimulus, but the specificity of these internal representations remains unclear. Here, we asked how similar the temporally unfolding neural representations of imagined music are compared to those during the original perceived experience. We also tested whether rhythmic motion can influence the neural representation of music during imagery as during perception. Participants first memorized six 1-min-long instrumental musical pieces with high accuracy. Functional MRI data were collected during: 1) silent imagery of melodies to the beat of a visual metronome; 2) same but while tapping to the beat; and 3) passive listening. During imagery, inter-subject correlation analysis showed that melody-specific temporal response patterns were reinstated in right associative auditory cortices. When tapping accompanied imagery, the melody-specific neural patterns were reinstated in more extensive temporal-lobe regions bilaterally. These results indicate that the specific contents of conscious experience are encoded similarly during imagery and perception in the dynamic activity of auditory cortices. Furthermore, rhythmic motion can enhance the reinstatement of neural patterns associated with the experience of complex sounds, in keeping with models of motor to sensory influences in auditory processing.
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Mapeo Encefálico , Imaginación/fisiología , Música/psicología , Estimulación Acústica , Adolescente , Adulto , Corteza Auditiva/fisiología , Percepción Auditiva/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Movimiento/fisiología , Discriminación de la Altura Tonal , Percepción de la Altura Tonal , Sensación/fisiología , Adulto JovenRESUMEN
During sleep we lack conscious awareness of the external environment. Yet, our internal mental state suggests that high-level cognitive processes persist. The nature and extent to which the external environment is processed during sleep remain largely unexplored. Here, we used an fMRI synchronization-based approach to examine responses to a narrative during wakefulness and sleep. The stimulus elicited the auditory network and a frontoparietal pattern of activity, consistent with high-level narrative plot-following. During REM sleep, the same frontoparietal pattern was observed in one of three participants, and partially in one other, confirming that it is possible to track and follow the moment-to-moment complexities of a narrative during REM sleep. Auditory network recruitment was observed in both non-REM and REM sleep, demonstrating preservation of low-level auditory processing, even in deep sleep. This novel approach investigating cognitive processing at different levels of awareness demonstrates that the brain can meaningfully process the external environment during REM sleep.
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Electroencefalografía , Sueño , Estimulación Acústica , Humanos , Sueño/fisiología , Sueño REM/fisiología , Vigilia/fisiologíaRESUMEN
We investigated how familiarity alters music and language processing in the brain. We used fMRI to measure brain responses before and after participants were familiarized with novel music and language stimuli. To manipulate the presence of language and music in the stimuli, there were four conditions: (1) whole music (music and words together), (2) instrumental music (no words), (3) a capella music (sung words, no instruments), and (4) spoken words. To manipulate participants' familiarity with the stimuli, we used novel stimuli and a familiarization paradigm designed to mimic "natural" exposure, while controlling for autobiographical memory confounds. Participants completed two fMRI scans that were separated by a stimulus training period. Behaviorally, participants learned the stimuli over the training period. However, there were no significant neural differences between the familiar and unfamiliar stimuli in either univariate or multivariate analyses. There were differences in neural activity in frontal and temporal regions based on the presence of language in the stimuli, and these differences replicated across the two scanning sessions. These results indicate that the way we engage with music is important for creating a memory of that music, and these aspects, over and above familiarity on its own, may be responsible for the robust nature of musical memory in the presence of neurodegenerative disorders such as Alzheimer disease.
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Música , Percepción Auditiva , Humanos , Lenguaje , Reconocimiento en Psicología , Lóbulo TemporalRESUMEN
The brain exhibits a complex temporal structure which translates into a hierarchy of distinct neural timescales. An open question is how these intrinsic timescales are related to sensory or motor information processing and whether these dynamics have common patterns in different behavioral states. We address these questions by investigating the brain's intrinsic timescales in healthy controls, motor (amyotrophic lateral sclerosis, locked-in syndrome), sensory (anesthesia, unresponsive wakefulness syndrome), and progressive reduction of sensory processing (from awake states over N1, N2, N3). We employed a combination of measures from EEG resting-state data: auto-correlation window (ACW), power spectral density (PSD), and power-law exponent (PLE). Prolonged neural timescales accompanied by a shift towards slower frequencies were observed in the conditions with sensory deficits, but not in conditions with motor deficits. Our results establish that the spontaneous activity's intrinsic neural timescale is related to the neural capacity that specifically supports sensory rather than motor information processing in the healthy brain.
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Esclerosis Amiotrófica Lateral/fisiopatología , Anestesia General , Encéfalo/fisiopatología , Percepción/fisiología , Estado Vegetativo Persistente/fisiopatología , Sueño/fisiología , Adulto , Anciano , Anestésicos Generales , Encéfalo/fisiología , Estudios de Casos y Controles , Electroencefalografía , Femenino , Humanos , Ketamina , Masculino , Persona de Mediana Edad , Sevoflurano , Análisis Espacio-Temporal , Factores de Tiempo , Adulto JovenRESUMEN
Long-term cognitive impairment is common among ICU survivors, but its natural history remains unclear. In this systematic review, we report the frequency of cognitive impairment in ICU survivors across various time points after ICU discharge that were extracted from 46 of the 3,350 screened records. Prior studies used a range of cognitive instruments, including subjective assessments (10 studies), single or screening cognitive test such as Mini-Mental State Examination or Trail Making Tests A and B (23 studies), and comprehensive cognitive batteries (26 studies). The mean prevalence of cognitive impairment was higher with objective rather than subjective assessments (54% [95% confidence interval (CI), 51-57%] vs. 35% [95% CI, 29-41%] at 3 months after ICU discharge) and when comprehensive cognitive batteries rather than Mini-Mental State Examination were used (ICU discharge: 61% [95% CI, 38-100%] vs. 36% [95% CI, 15-63%]; 12 months after ICU discharge: 43% [95% CI, 10-78%] vs. 18% [95% CI, 10-20%]). Patients with acute respiratory distress syndrome had higher prevalence of cognitive impairment than mixed ICU patients at ICU discharge (82% [95% CI, 78-86%] vs. 48% [95% CI, 44-52%]). Although some studies repeated tests at more than one time point, the time intervals between tests were arbitrary and dictated by operational limitations of individual studies or chosen cognitive instruments. In summary, the prevalence and temporal trajectory of ICU-related cognitive impairment varies depending on the type of cognitive instrument used and the etiology of critical illness. Future studies should use modern comprehensive batteries to better delineate the natural history of cognitive recovery across ICU patient subgroups and determine which acute illness and treatment factors are associated with better recovery trajectories.
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Disfunción Cognitiva/epidemiología , Disfunción Cognitiva/etiología , Cuidados Críticos/psicología , Enfermedad Crítica/terapia , Sobrevivientes/psicología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Medición de RiesgoRESUMEN
BACKGROUND: Severe brain injury is a leading cause of death and disability. Diagnosis and prognostication are difficult, and errors occur often. Novel neuroimaging methods can improve diagnostic and prognostic accuracy, especially in patients with prolonged disorders of consciousness (PDoC). Yet it is currently unknown how family caregivers understand this information, raising ethical concerns that disclosure of neuroimaging results could result in therapeutic misconception or false hope. METHODS: To examine these ethical concerns, we conducted semi-structured interviews with caregivers of patients with PDoC who were enrolled in a concurrent neuroimaging research program designed to detect covert consciousness following severe brain injury. Caregivers held surrogate decision-making status for a patient. Interviews were conducted at two time points for each caregiver. The first interview occurred before the disclosure of neuroimaging results. The second occurred after disclosure. Descriptive analysis was applied to the data of four interview topics: (1) expectations for neuroimaging; (2) reactions to evidence of preserved cognition; (3) reactions to null results; and (4) understanding of the results and study. RESULTS: Twelve caregivers participated in the study; two caregivers shared surrogate decision-making status for one patient with PDoC. Twenty-one interviews were completed; one caregiver declined to participate in the post-disclosure interview. Three patients with PDoC associated with the study displayed evidence of covert consciousness. Overall, caregivers understood the neuroimaging research and results. Caregivers who received results of covert consciousness were generally pleased. However, there was some variation in expectations and reactions to these data and null results. CONCLUSION: This study, for the first time, reveals caregiver expectations for and reactions to neuroimaging evidence of covert consciousness in patients with PDoC. Caregivers understood the neuroimaging research and results, casting doubt on speculative ethical concerns regarding therapeutic misconception and false hope. However, disclosure of neuroimaging result could be improved. Pre-disclosure consultations might assist professionals in shaping caregiver expectations. Standardization of disclosure might also improve comprehension of the results.
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Lesiones Encefálicas , Cuidadores , Estado de Conciencia , Trastornos de la Conciencia , Humanos , NeuroimagenRESUMEN
Objective: To understand the multiple and sometimes conflicting roles substitute decision makers (SDMs) of individuals in a vegetative state (VS), minimally conscious state (MCS), or with locked-in syndrome (LIS) perform while caring for a loved one and the competing priorities derived from these roles.Methods: We conducted semi-structured qualitative interviews using a constructive-grounded theory design. Twelve SDMs, who were also family members for 11 patients, were interviewed at two time points (except one) for a total of 21 in-depth interviews.Results: Participants described that caregiving is often the central role which they identify as their top priority and around which they coordinate and to some extent subordinate their other roles. In addition to caregiving, they participated in a wide variety of roles, which were sometimes in conflict, as they became caregivers for a loved one with chronic and complex needs. SDMs described the caregiver role as complex and intense that lead to physical, emotional, social, and economic burdens.Conclusion: SDMs report high levels of burdens in caring for a person with a prolonged disorder of consciousness. Lack of health system support that recognized the broader context of SDMs lives, including their multiple competing priorities, was a major contributing factor.
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Cuidadores , Estado de Conciencia , Carga del Cuidador , Familia , Humanos , Estado Vegetativo Persistente , Investigación Cualitativa , Apoyo SocialRESUMEN
Primary Objective: To understand the experiences of family members of individuals in a locked-in state (LIS), minimally conscious state (MCS), or vegetative state (VS) with the health-care system when caring for their family member.Research Design: The study adopted a qualitative descriptive approach drawing on central tenets of constructivist grounded theory described by Charmaz. Our analysis drew on emphasizing connections between theory, concepts, and empirical data using a constant comparative method.Methods and Procedures: Semi-structured interviews were conducted with family members of individuals in a LIS, MCS, or VS. Participants were recruited between June 2014 and December 2016.Main Outcomes and Results: 22 interviews were conducted, which comprised interviews with 12 family members. The following themes were identified: care coordination challenges, lack of flexibility in health-care policies, and inappropriate care settings.Conclusions: Family members of individuals in a LIS, MCS, or VS described playing a significant role in the lives of their family member. Based on the results of this study, flexibility in health-care policies and/or programming should be adopted in the face of the challenges identified. Implementation of interventions to support caregivers and transitions is increasingly important.