Modulation of amygdala activity for emotional faces due to botulinum toxin type A injections that prevent frowning

Is Acupuncture Effective in Diminishing Frown Lines? Evidence From a Randomized Controlled Trial

BACKGROUND

As life expectancy rises, facial rejuvenation has gained significance.

AIMS

This study aimed to evaluate the effects of body and facial acupuncture on reducing frown lines in women aged 30-59 in Mashhad, Iran.

PATIENTS/METHODS

In this double-arm randomized wait-list controlled trial, 72 participants were randomly assigned to either an intervention group, receiving facial and body acupuncture twice weekly for 6 weeks, or a control group with no treatment. The primary outcome was assessed using the Global Aesthetic Improvement Scale (GAIS) based on standardized photographs. Secondary outcomes included the Subject Satisfaction Scale (SSS) and Quality of Life (QOL) scores. Measurements were taken at three time points: week 0 (pre-treatment), week 7 (post-treatment), and week 12 (follow-up).

RESULTS

At week 7, 63% of the intervention group showed reduced frown lines at rest, and 72% during maximum frowning, significantly outperforming the control group. The improvements observed in the intervention group persisted at week 12 with 68.6% at rest and 57.2% at maximum frown. The SSS indicated that 72.2% and 62.9% of the intervention group were satisfied with their frown lines at weeks 7 and 12, respectively. Notable QOL improvements in social functioning were observed in the intervention group compared to the control group at both weeks 7 and 12. No serious adverse effects were reported; minor bleeding occurred in 4.86% of treatment sessions, resulting in bruising in 0.69%.

CONCLUSION

This study demonstrates that facial and body acupuncture is an effective and safe method for reducing frown lines.

TRIAL REGISTRATION

IRCT20230204057316N1 (https://irct.behdasht.gov.ir/trial/68408).

Facial Symmetry Enhancement and Brain Network Modifications in Facial Palsy Patients after Botulinum Toxin Type A Treatment

BACKGROUND

Facial palsy, often resulting from trauma or iatrogenic treatments, leads to significant aesthetic and functional impairment. Surgical interventions, such as masseteric-to-facial nerve transfer combined with static suspension, are frequently recommended to restore facial nerve function and symmetry.

METHODS

This study examined the impact of botulinum toxin type A (BoNT-A) treatment on the unaffected side with regard to facial symmetry and brain connectivity in patients with severe oral commissure droop from facial nerve damage. Patients were divided into 2 groups: 1 group received BoNT-A injections on the unaffected side, and the other did not.

RESULTS

The authors' findings revealed that BoNT-A treatment not only improved facial symmetry but also induced significant modifications in brain functional network connectivity. These modifications extended beyond the sensorimotor network, involving high-level cognitive processes, and exhibited a significant correlation with the degree of facial asymmetry.

CONCLUSIONS

These results provide valuable insights into the mechanisms underlying the positive effects of BoNT-A intervention on motor recovery and brain plasticity in facial palsy patients. Furthermore, the study emphasizes the importance of a multidisciplinary approach to facial palsy rehabilitation. Understanding these intricate interactions between facial symmetry restoration and brain network adaptations may pave the way for more effective treatments and improved quality of life for individuals dealing with facial palsy.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Depression Treatment: Is There a Role for Botulinum Toxin Type A?

This study aimed to determine whether botulinum toxin type A injected into the muscles of the upper third of the face has antidepressant effects in patients diagnosed with depression. Studies seeking a relationship between botulinum toxin type A and its antidepressant effects were considered in this review. All studies concluded that the facial expression muscles present positive feedback to the brain and enhance mood states. Botulinum toxin when applied to the corrugator and procerus muscles has an antidepressant effect.

On the Role of Sensorimotor Experience in Facial Expression Perception

Humans recognize the facial expressions of others rapidly and effortlessly. Although much is known about how we perceive expressions, the role of facial experience in shaping this remarkable ability remains unclear. Is our perception of expressions linked to how we ourselves make facial expressions? Are we better at recognizing other's facial expressions if we are experts at making the same expressions ourselves? And if we could not make facial expressions at all, would it impact our ability to recognize others' facial expressions? The current article aims to examine these questions by explicating the link between facial experience and facial expression recognition. It includes a comprehensive appraisal of the related literature and examines three main theories that posit a connection between making and recognizing facial expressions. First, recent studies in individuals with Moebius syndrome support the role of facial ability (i.e., the ability to move one's face to make facial expressions) in facial expression recognition. Second, motor simulation theory suggests that humans recognize others' facial expressions by covertly mimicking the observed expression (without overt motor action) and that this facial mimicry helps us identify and feel the associated emotion. Finally, the facial feedback hypothesis provides a framework for enhanced emotional experience via proprioceptive feedback from facial muscles when mimicking a viewed facial expression. Evidence for and against these theories is presented as well as some considerations and outstanding questions for future research studies investigating the role of facial experience in facial expression perception.

Correlation between blepharospasm and psychological diseases: the anxiety, depression and sleep disorder study

AIM

To investigate the relationship between benign essential blepharospasm (BEB) symptoms and depression/anxiety/sleep disorder in a prospective manner and to determine whether treatment the BEB with botulinum toxin type A (BoNT/A) can impact psychological symptoms.

METHODS

This prospective interventional case series recruited 61 adults with evidence of BEB. Patients were administered the Jankovic Rating Scale (JRS), the Blepharospasm Disability Index (BSDI), Personal Health Questionnaire Depression Scale (PHQ-8), Generalized Anxiety Disorder 7-item scale (GAD-7) and the Athens insomnia scale (AIS) to evaluate the severity of BEB symptoms, depression, anxiety and sleep disorder before and 1wk, 1, 3mo after the BoNTA treatment. Statistical analysis was performed to assess the relationships between changes in the survey scores.

RESULTS

The mean score for JRS, BSDI, PHQ-8, and GAD-7 improved significantly (P<0.0001), respectively, compared to the initial visit at follow-up. At baseline, worse BSDI scores were correlated with worse GAD-7 and PHQ-8, but not with worse AIS. At 1mo follow-up visit, there was no correlation between change in BSDI and PHQ-8/AIS, the change in GAD-7 showed a mild association with change in BSDI. The change in BSDI was correlated with the change in both PHQ-8 and GAD-7 in the subgroup of patients without a prior diagnosis of depression or anxiety. Patient satisfaction with BoNT/A treatment reached the highest at 1mo of follow-up (83.6%, 51/61).

CONCLUSION

BEB may lead to psychological diseases. BoNT/A can significantly improve motor and non-motor symptoms of BEB, which emphasize the effectiveness of BoNT/A and therefore pave the way for its use in the field of psychiatry. However, further research is needed to confirm these findings and understand the underlying mechanisms.

A simple psychophysical procedure separates representational and noise components in impairments of speech prosody perception after right-hemisphere stroke

After a right hemisphere stroke, more than half of the patients are impaired in their capacity to produce or comprehend speech prosody. Yet, and despite its social-cognitive consequences for patients, aprosodia following stroke has received scant attention. In this report, we introduce a novel, simple psychophysical procedure which, by combining systematic digital manipulations of speech stimuli and reverse-correlation analysis, allows estimating the internal sensory representations that subtend how individual patients perceive speech prosody, and the level of internal noise that govern behavioral variability in how patients apply these representations. Tested on a sample of N = 22 right-hemisphere stroke survivors and N = 21 age-matched controls, the representation + noise model provides a promising alternative to the clinical gold standard for evaluating aprosodia (MEC): both parameters strongly associate with receptive, and not expressive, aprosodia measured by MEC within the patient group; they have better sensitivity than MEC for separating high-functioning patients from controls; and have good specificity with respect to non-prosody-related impairments of auditory attention and processing. Taken together, individual differences in either internal representation, internal noise, or both, paint a potent portrait of the variety of sensory/cognitive mechanisms that can explain impairments of prosody processing after stroke.

Sensorimotor regulation of facial expression - An untouched frontier

Facial expression is a critical form of nonverbal social communication which promotes emotional exchange and affiliation among humans. Facial expressions are generated via precise contraction of the facial muscles, guided by sensory feedback. While the neural pathways underlying facial motor control are well characterized in humans and primates, it remains unknown how tactile and proprioceptive information reaches these pathways to guide facial muscle contraction. Thus, despite the importance of facial expressions for social functioning, little is known about how they are generated as a unique sensorimotor behavior. In this review, we highlight current knowledge about sensory feedback from the face and how it is distinct from other body regions. We describe connectivity between the facial sensory and motor brain systems, and call attention to the other brain systems which influence facial expression behavior, including vision, gustation, emotion, and interoception. Finally, we petition for more research on the sensory basis of facial expressions, asserting that incomplete understanding of sensorimotor mechanisms is a barrier to addressing atypical facial expressivity in clinical populations.

Botulinum Toxin Injections for Psychiatric Disorders: A Systematic Review of the Clinical Trial Landscape

Botulinum toxin type A (BONT-A) has shown promise in improving the mood-related symptoms of psychiatric disorders by targeting muscles linked to the expression of negative emotions. We conducted a systematic review of past and ongoing efficacy trials of BONT-A therapy for psychiatric disorders to identify relevant trends in the field and discuss the refinement of therapeutic techniques. A comprehensive search for published clinical trials using BONT-A injections for psychiatric disorders was performed on 4 May 2023 through OVID databases (MEDLINE, Embase, APA PsycINFO). Unpublished clinical trials were searched through the ClinicalTrials.gov and International Clinical Trial Registry Platform public registries. The risk of bias was assessed using the JBI Critical Appraisal tools for use in systematic reviews. We identified 21 studies (17 published, 4 unpublished clinical trials) involving 471 patients. The studies focused on evaluating the efficacy of BONT-A for major depressive, borderline personality, social anxiety, and bipolar disorders. BONT-A was most commonly injected into the glabellar area, with an average dose ranging between 37.75 U and 44.5 U in published studies and between 32.7 U and 41.3 U in unpublished trials. The results indicated significant symptom reductions across all the studied psychiatric conditions, with mild adverse effects. Thus, BONT-A appears to be safe and well-tolerated for psychiatric disorders of negative affectivity. However, despite the clinical focus, there was a noted shortage of biomarker-related assessments. Future studies should focus on pursuing mechanistic explorations of BONT-A effects at the neurobiological level.

Machine Learning-Based Interpretable Modeling for Subjective Emotional Dynamics Sensing Using Facial EMG

Understanding the association between subjective emotional experiences and physiological signals is of practical and theoretical significance. Previous psychophysiological studies have shown a linear relationship between dynamic emotional valence experiences and facial electromyography (EMG) activities. However, whether and how subjective emotional valence dynamics relate to facial EMG changes nonlinearly remains unknown. To investigate this issue, we re-analyzed the data of two previous studies that measured dynamic valence ratings and facial EMG of the corrugator supercilii and zygomatic major muscles from 50 participants who viewed emotional film clips. We employed multilinear regression analyses and two nonlinear machine learning (ML) models: random forest and long short-term memory. In cross-validation, these ML models outperformed linear regression in terms of the mean squared error and correlation coefficient. Interpretation of the random forest model using the SHapley Additive exPlanation tool revealed nonlinear and interactive associations between several EMG features and subjective valence dynamics. These findings suggest that nonlinear ML models can better fit the relationship between subjective emotional valence dynamics and facial EMG than conventional linear models and highlight a nonlinear and complex relationship. The findings encourage emotion sensing using facial EMG and offer insight into the subjective-physiological association.

Botox (onabotulinumtoxinA) mechanism of action

Studies in the 1920s found that botulinum neurotoxin type A (BoNT/A) inhibited the activity of motor and parasympathetic nerve endings, confirmed several decades later to be due to decreased acetylcholine release. The 1970s were marked by studies of cellular mechanisms aided by use of neutralizing antibodies as pharmacologic tools: BoNT/A disappeared from accessibility to neutralizing antibodies within minutes, although it took several hours for onset of muscle weakness. The multi-step mechanism was experimentally confirmed and is now recognized to consist broadly of binding to nerve terminals, internalization, and lysis or cleavage of a protein (SNAP-25: synaptosomal associated protein-25 kDa) that is part of the SNARE (Soluble NSF Attachment protein REceptor) complex needed for synaptic vesicle docking and fusion. Clinical use of the BoNT/A product onabotulinumtoxinA was based on its ability to reduce muscle contractions via inhibition of acetylcholine from motor terminals. Sensory mechanisms of onabotulinumtoxinA have now been identified, supporting its successful treatment of chronic migraine and urgency in overactive bladder. Exploration into migraine mechanisms led to anatomical studies documenting pain fibers that send axons through sutures of the skull to outside the head-a potential route by which extracranial injections could affect intracranial processes. Several clinical studies have also identified benefits of onabotulinumtoxinA in major depression, which have been attributed to central responses induced by feedback from facial muscle and skin movement. Overall, the history of BoNT/A is distinguished by basic science studies that stimulated clinical use and, conversely, clinical observations that spurred basic research into novel mechanisms of action.