A 10-day theta burst stimulation intervention facilitates the clinical rehabilitation of patients following an isolated limb fracture: A longitudinal SHAM-controlled pilot study.

OBJECTIVE: We investigated if theta burst stimulation (TBS) could enhance recovery by reducing key symptoms when implemented acutely post-fracture in participants with an isolated upper limb fracture (IULF). METHODS/DESIGN: This was a pilot study with a randomized matched pair, sham-controlled, participant-blind design of a 10-day prolonged continuous TBS protocol. Two main groups were included: I) participants with IULF receiving active TBS; and II) patients with IULF receiving SHAM/placebo. Another group (III) of healthy individuals were the reference group. Disability and pain intensity were collected through questionnaires (DASH & NRA) at three timepoints (baseline; 72 h post-intervention & 3 months post-injury). Group III completed the baseline assessment. RESULTS: 79 participants were enrolled. Individuals in the ACTIVE and SHAM groups had similar baseline measures. For disability, the interaction between Intervention and Time approached significance (F = 2.33; p = 0.11), whereas it was significant for pain (F = 3.42; p = 0.04). At 3 months post-injury, the ACTIVE group reported reduced disability (F = 4.71; p = 0.04) and pain (F = 5.84; p = 0.02) at three months post-injury compared to the SHAM group, with clinical measures from ACTIVE group being like controls. CONCLUSIONS: In IULF patients, a 10-day TBS intervention implemented acutely post-trauma had beneficial effects on symptoms of functional recovery and pain at 3 months post-trauma.

Effects of emotion and emotional ambiguity on early visual event-related potentials.

The modulation of early sensory event-related potentials such as the P1, N1, and N170 by emotion and emotional ambiguity is still controversial. Some studies have found a modulation of one or all of these components by one or both of these factors, whereas others have failed to show such results. The objective of this study was to investigate the effects of emotion and ambiguity on the behavioral and electrophysiological responses to a morphed emotion recognition task. Thirty-seven healthy participants (19 men) completed an emotion recognition task where photographs of a male face expressing the six basic emotions morphed with another emotion (in a proportion ranging from 26% to 74%) were randomly presented while electroencephalography was recorded. After each face presentation, participants were asked to identify the facial emotion. We found an emotional effect on the P1, N1, and N170, with greater amplitudes for some emotional facial expressions than for others. However, we found no significant emotional ambiguity effect or interaction between emotion and ambiguity for any of these components. These findings suggest that computation of emotional facial expressions (regardless of their ambiguity) occurs from the early stages of brain processing. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Interhemispheric differences in P1 and N1 amplitude in EEG and MEG differ across older individuals with a concussion compared with age-matched controls.

We studied the effects of mild traumatic brain injury (mTBI) in an aging population. We examined visual search with event-related potentials (ERPs) and event-related fields (ERF) for a lateral color singleton focusing on the P1 and N1 in each hemisphere. Forty participants (19 mTBI and 21 controls) aged 50 to 72 performed a visual search task, while we recorded their magnetoencephalogram (MEG) with simultaneous electroencephalogram (EEG). We compared visual ERPs and ERFs and associated cortical activity estimated using MEG source localization. Relative to matched controls, participants with an mTBI had a smaller P1 in the left hemisphere and a smaller N1 in the right hemisphere. Also, mTBI participants showed inversed activation patterns across the hemispheres during the N1 in MEG compared with controls. This is the first study to investigate the impact of mTBI on neuronal source activations during early visual processing in an aging population. Results showed that when aging individuals suffer from an mTBI, there are perturbations in the amplitude and hemispheric dominance patterns in the visual P1 and N1 responses that are visible for months to years following the injury. Our findings indicate that mTBI can lead to modifications of sensory and/or perceptual responses, suggesting possible adaptive functional reorganization following mTBI.

Subtle long-term cognitive effects of a single mild traumatic brain injury and the impact of a three-month aerobic exercise intervention.

BACKGROUND: Although there is a growing body of literature on the impact of multiple concussions on cognitive function with aging, less is known about the long-term impact of sustaining a single mild traumatic brain injury (mTBI). Additionally, very few interventions exist to treat mTBI patients and prevent a possible accelerated cognitive decline. This study aimed to: 1) examine the long-term effects of a single mTBI on cognition in patients aged between 55 and 70 years old; and 2) evaluate the cognitive effects of an aerobic exercise program for these patients. METHODS: Thirty-five participants (average age: 58.89, SD=4.14) were assessed using neuropsychological tests. Among them, 18 hadsustained a mTBI two to seven years earlier. Significant differences in information processing speed, executive function and visual memory were found between controls and mTBI patients. Sixteen of the mTBI patients then engaged in a 12-week physical exercise program. They were divided into equivalent groups: 1) aerobic training (cycle ergometers); or 2) stretching exercises. The participants' cardiopulmonary fitness (VO2max) was evaluated pre- and postintervention and neuropsychological tests were re-administered postintervention. RESULTS: Participants from the aerobic group significantly improved their fitness compared to the stretching group. However, no between-group difference was found on neuropsychological measures postintervention. CONCLUSIONS: In summary, this study shows long-term cognitive effects of mTBI in late adulthood patients. Moreover, the controlled, 12-week aerobic exercise program did not lead to cognitive improvements in our small mTBI sample. Lastly, future directions in optimizing mTBI intervention are discussed.

Mild traumatic brain injury: The effect of age at trauma onset on brain structure integrity.

Mounting evidence suggests that mild traumatic brain injuries (mTBI) have long-term effects that interact with the aging process to precipitate cognitive decline. This line of research predicts that early exposure to brain trauma is particularly detrimental to long-term brain integrity. However, a second line of research into the effects of age at trauma onset predict that older brains are more vulnerable to the effects of mTBI than younger brains. We sought to determine whether patients who sustain a mTBI earlier in life fare better than patients who sustain a mTBI at an older age. We conducted a multi-cohort, case-control study, with participants randomly sampled from a population of patients with a history of mTBI. We recruited two cohorts of aging participants (N = 74, mean [SD] = 61.16 [6.41]) matched in age and education levels that differed in only one respect: age at mTBI onset. One cohort sustained their concussion in their early twenties (24.60 [6.34] y/o), the other in their early sixties (61.05 [4.90] y/o). Each mTBI cohort had its own matched control group. Participants underwent high-resolution MRI at 3 Tesla for T1 and diffusion-weighted images (DWI) acquisition. Images were processed and analyzed using Deformation-Based Morphometry and DWI Tract-Based Spatial Statistics to identify group differences in a 2 × 2 ANOVA design. Results showed a significant interaction on DWI measures of white matter integrity indicating larger anomalies in participants who sustained a mTBI at a younger age (F1,70, P < .05, FDR corrected). These findings suggest that mTBI initiates a lifelong neurodegeneration process that outweighs the risks associated with sustaining a mTBI at an older age. Implications are important for young athletes' populations exposed to the risk of mTBI in the practice of their sports and for retired athletes aging with a history of concussions sustained at a younger age.

Motor Learning Improvement Remains 3 Months After a Multisession Anodal tDCS Intervention in an Aging Population.

Healthy aging is associated with decline of motor function that can generate serious consequences on the quality of life and safety. Our studies aim to explore the 3-month effects of a 5-day multisession anodal transcranial direct current stimulation (a-tDCS) protocol applied over the primary motor cortex (M1) during motor sequence learning in elderly. The present sham-controlled aging study investigated whether tDCS-induced motor improvements previously observed 1 day after the intervention persist beyond 3 months. A total of 37 cognitively-intact aging participants performed five consecutive daily 20-min sessions of the serial-reaction time task (SRTT) concomitant with either anodal (n = 18) or sham (n = 19) tDCS over M1. All participants performed the Purdue Pegboard Test and transcranial magnetic stimulation (TMS) measures of cortical excitability were collected before, 1 day after and 3 months after the intervention. The last follow-up session also included the execution of the trained SRTT. The main findings are the demonstration of durable effects of a 5-day anodal tDCS intervention at the trained skill, while the active intervention did not differ from the sham intervention at both the untrained task and on measures of M1-disinhibition. Thus, the current article revealed for the first time the durability of functional effects of a-tDCS combined with motor training after only 5 days of intervention in an aging population. This finding provides evidence that the latter treatment alternative is effective in achieving our primary motor rehabilitation goal, that is to allow durable motor training effects in an aging population.

Multisession anodal transcranial direct current stimulation induces motor cortex plasticity enhancement and motor learning generalization in an aging population.

OBJECTIVES: The present aging study investigated the impact of a multisession anodal-tDCS protocol applied over the primary motor cortex (M1) during motor sequence learning on generalization of motor learning and plasticity-dependent measures of cortical excitability. METHODS: A total of 32 cognitively-intact aging participants performed five consecutive daily 20-min sessions of the serial-reaction time task (SRTT) concomitant with either anodal (n = 16) or sham (n = 16) tDCS over M1. Before and after the intervention, all participants performed the Purdue Pegboard Test (PPT) and Transcranial Magnetic Stimulation (TMS) measures of cortical excitability were collected. RESULTS: Relative to sham, participants assigned to the anodal-tDCS intervention revealed significantly greater performance gains on both the trained SRTT and the untrained PPT as well as a greater disinhibition of long-interval cortical inhibition (LICI). Generalization effects of anodal-tDCS significantly correlated with LICI disinhibition. CONCLUSION: Anodal-tDCS facilitates motor learning generalisation in an aging population through intracortical disinhibition effects. SIGNIFICANCE: The current findings demonstrate the potential clinical utility of a multisession anodal-tDCS over M1 protocol as an adjuvant to motor training in alleviating age-associated motor function decline. This study also reveals the pertinence of implementing brain stimulation techniques to modulate age-associated intracortical inhibition changes in order to facilitate motor function gains.