RESUMEN
Oral ketamine has shown to be a rapid-acting antidepressant and a potential treatment option for suicidality, however, repeated doses are often required. Objective markers of prolonged treatment response are needed to help individuals and clinicians make informed treatment decisions. This secondary analysis sought to identify objective electrophysiological predictors of both prolonged response and dose sensitivity to low-dose oral ketamine in people with chronic suicidality. Individuals with a Beck Scale for Suicide Ideation total score (BSS) ≥ 6 (N = 29) completed a six-week ketamine treatment, pre-treatment electroencephalography and follow-up assessment of suicidality (four weeks from the final ketamine dose). Prolonged response was observed in 52% of participants (follow-up BSS reduced by 50% or ≤6); nearly half were prolonged non-responders. There was decisive evidence for a predictive Bayesian linear regression model with follow-up BSS score as the response variable and pre-treatment auditory evoked power bands as predictors (theta, alpha and beta frequencies, BF10 = 17,948, R2 = 0.70). A Bayesian one-way ANOVA indicated strong evidence for a model of positive association between auditory evoked power and ketamine dose sensitivity (theta-alpha BF+0 = 108, effect size δ = 1.3, 95% CI 0.5-2.1; high-beta BF+0 = 7.4, δ = 0.8, 95% CI 0.1-1.6). Given auditory evoked power may index serotonin neurotransmission, these results suggest that a prolonged response to ketamine may, in part, be mediated by pre-treatment serotonergic functioning. In addition, the observed beta power differences may arise from GABAergic functioning. These suicidality phenotypes, identifiable by pre-treatment electrophysiology, may aid diagnosis, treatment selection and prediction of prolonged treatment outcome.
Asunto(s)
Ketamina , Suicidio , Humanos , Ketamina/uso terapéutico , Teorema de Bayes , Antidepresivos/uso terapéutico , Fenotipo , Ideación SuicidaRESUMEN
The current study sought to examine the discriminant validity of 3 commonly used measures of mindfulness. The discriminative ability of the Mindful Attention Awareness Scale (MAAS), the Five Factor Mindfulness Questionnaire (FFMQ), and a breath counting task (BCT) was assessed in a randomized control trial involving an 8-week mindfulness training (MT) condition (n = 53) and an active control computerized attention training (CT) program (n = 33). No evidence to support the discriminant validity of MAAS or FFMQ scores was found, as these self-report measures responded to both the MT and CT conditions. Breath counting scores however demonstrated unique responsiveness to the MT program, suggesting this behavioral task may be useful in measuring changes in mindfulness as it closely resembles core cognitive processes trained during this practice. Implications of these findings for the construct validity of both self-report and behavioral measures of mindfulness are discussed, along with the suitability of current mindfulness-based interventions in studies aiming to assess mindfulness outcomes. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
Asunto(s)
Atención , Atención Plena/métodos , Frecuencia Respiratoria , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Psicometría , Reproducibilidad de los Resultados , Autoinforme , Encuestas y CuestionariosRESUMEN
Mindfulness has been shown to improve attentional performance, which is known to decline in aging. Long-latency electroencephalographic (EEG) event-related potential (ERP) changes have been reported immediately after mindfulness training, however the enduring stability of these effects is unknown. Furthermore, the ability of mindfulness to impact earlier stages of information processing is unclear. We examined neural activation using high density EEG in older adults engaged in mindfulness training to examine the long-term stability of training effects. After 6 months of training, mindfulness practitioners displayed enhanced neural activation during sensory encoding and perceptual processing of a visual cue. Enhanced perceptual processing of a visual cue was associated with increased neural activation during post-perceptual processing of a subsequent target. Similar changes were not observed in a control group engaged in computer-based attention training over the same period. Neural changes following mindfulness training were accompanied by behavioural improvements in attentional performance. Our results are suggestive of increased efficiency of the neural pathways subserving bottom-up visual processing together with an enhanced ability to mobilise top-down attentional processes during perceptual and post-perceptual processing following mindfulness training. These results indicate that mindfulness may enhance neural processes known to deteriorate in normal aging and age-related neurodegenerative diseases.
Asunto(s)
Atención Plena , Neuronas/fisiología , Percepción Visual/fisiología , Anciano , Área Bajo la Curva , Atención/fisiología , Conducta , Encéfalo/fisiología , Análisis por Conglomerados , Potenciales Evocados/fisiología , Femenino , Humanos , MasculinoRESUMEN
The aim of this study was to determine the effect of age on the relationship between cerebrovascular function and the neural bases of sustained attention. Twenty-seven healthy young adults (aged 18-30 years) and 24 older adults (60-75 years) underwent assessments of cerebrovascular function and sustained attention. Blood flow velocity of the middle cerebral artery was assessed via Transcranial Doppler Ultrasound, during seated rest, in response to hypocapnic breathing (cerebrovascular reactivity) and during a repeated sit-to-stand procedure (pressure-flow response). Attentional processing was assessed using the N2 and P3 components of the event-related potential during a two-tone auditory oddball task. Poorer pressure-flow responses were significantly associated with reductions in N2 and P3 amplitude in the old group (b = -0.50, p = .029 and b = -0.46, p = .045), but not the young group. These results suggest that alterations in the brain's capacity to combat reductions in perfusion pressure are associated with age-related differences in attentional processing, supporting the hypothesis that cerebrovascular hemodynamic disturbances play a role in age-related cognitive decline.
Asunto(s)
Atención/fisiología , Velocidad del Flujo Sanguíneo/fisiología , Circulación Cerebrovascular/fisiología , Adolescente , Adulto , Anciano , Disfunción Cognitiva , Potenciales Evocados , Femenino , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Arteria Cerebral Media/diagnóstico por imagen , Sedestación , Ultrasonografía Doppler Transcraneal , Adulto JovenRESUMEN
Evidence suggests that cerebrovascular hemodynamic disturbances underlie cognitive deterioration secondary to cardiovascular disease (CVD), including manifestations other than stroke, but the mechanisms remain unclear. To date, the majority of studies have used neuropsychological measures validated for the detection of clinically significant cognitive decline but lack the sensitivity to accurately detect subclinical or subtle cognitive changes. The N2 and P3 components of the event-related potential are sensitive markers of attention and cognitive processing, and are valuable in the assessment of age-related cognitive changes and neurodegenerative disease. The aims of this study were to test (a) the sensitivity of N2 and P3 components in differentiating older adults with CVD from healthy controls, and (b) whether cerebrovascular hemodynamics are associated with alterations in attention in persons with non-stroke CVD. Older adults with CVD (nâ¯=â¯20) and healthy older adults (nâ¯=â¯20) without cognitive impairment or history of stroke and matched for age, were recruited. Cerebral blood flow velocity of the middle cerebral artery (MCAv) and Gosling's Pulsatility Index (PI) were assessed using Transcranial Doppler ultrasound (TCD). ERPs were elicited using a two-tone auditory oddball task. N2 amplitude was significantly reduced in the CVD group at midline frontal, central and parietal sites (pâ¯<â¯.05, dâ¯>â¯0.6). No significant group differences were observed in N2 latency, P3 amplitude, or P3 latency. Further, MCAv and PI were strongly associated with N2 amplitude in the CVD group, such that greater MCAv was associated with reductions in N2 amplitude (bâ¯=â¯-0.58, pâ¯=â¯.018), whilst PI was associated with increases in N2 amplitude (bâ¯=â¯0.66, pâ¯=â¯.006). No relationships between MCAv or PI with N2 or P3 ERP components were observed in the healthy control group. The data reported here suggest that a reduction in N2 amplitude may be an important objective indicator of subclinical cognitive and attentional alterations in non-stroke CVD, and support the notion that cerebrovascular hemodynamic disturbances play a role in the pathogenesis of cognitive deterioration secondary to non-stroke CVD.
Asunto(s)
Atención/fisiología , Enfermedades Cardiovasculares/complicaciones , Enfermedades Cardiovasculares/fisiopatología , Disfunción Cognitiva/etiología , Disfunción Cognitiva/fisiopatología , Anciano , Anciano de 80 o más Años , Aterosclerosis/fisiopatología , Circulación Cerebrovascular/fisiología , Cognición , Potenciales Evocados/fisiología , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Neurodegenerativas/fisiopatologíaRESUMEN
Aging is associated with a decline in performance and speed of attentional processing. Mindfulness has been shown to enhance attentional performance, however evidence of this is lacking in aging cohorts. A longitudinal RCT was conducted to examine the effect of mindfulness training on attentional performance in healthy older adults (n = 49) together with an active control computer-based attention training group (n = 30). While both groups displayed decreased N2 amplitudes at frontal and central regions during an auditory oddball task after training, only the mindfulness group showed reductions in frontal N2 and P3 latency. These results suggest that programs targeting sustained attention may result in efficient allocation of attentional resources in older adults. In particular, mindfulness may enhance the speed of attentional processes which are known to decline in aging, thereby providing benefits against age-related cognitive decline.
Asunto(s)
Atención/fisiología , Electroencefalografía , Potenciales Evocados/fisiología , Anciano , Análisis de Varianza , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Atención Plena/métodos , Asignación de RecursosRESUMEN
A capacity model of mindfulness is adopted to differentiate the cognitive faculty of mindfulness from the metacognitive processes required to cultivate this faculty in mindfulness training. The model provides an explanatory framework incorporating both the developmental progression from focussed attention to open monitoring styles of mindfulness practice, along with the development of equanimity and insight. A standardised technique for activating these processes without the addition of secondary components is then introduced. Mindfulness-based interventions currently available for use in randomised control trials introduce components ancillary to the cognitive processes of mindfulness, limiting their ability to draw clear causative inferences. The standardised technique presented here does not introduce such ancillary factors, rendering it a valuable tool with which to investigate the processes activated in mindfulness practice.
Asunto(s)
Atención/fisiología , Memoria a Corto Plazo/fisiología , Metacognición/fisiología , Atención Plena/métodos , Modelos Psicológicos , HumanosRESUMEN
Existing models of mindfulness describe the self-regulation of attention as primary, leading to enhanced decentering and ability to access and override automatic cognitive processes. This study compared 23 experienced and 21 non-meditators on tests of mindfulness, attention, decentering, and ability to override automatic cognitive processes to test the cognitive mechanisms proposed to underlie mindfulness practice. Experienced meditators had significantly higher mindfulness and decentering than non-meditators. No significant difference between groups was found on measures of attention or ability to override automatic processes. These findings support the prediction that mindfulness leads to enhanced decentering, but do not support the cognitive mechanisms proposed to underlie such enhancement. Since mindfulness practice primarily involves internally directed attention, it may be the case that cognitive tests requiring externally directed attention and timed responses do not accurately assess mindfulness-induced cognitive changes. Implications for the models of mindfulness and future research are discussed.