Revisión de las técnicas de evaluación e intervención en la parálisis facial. Valoración de su eficacia

El nervio facial está compuesto por fibras motoras y sensitivas encargadas de inervar la musculatura facial, algunas glándulas y de procesar información gustativa. La parálisis facial impide el correcto funcionamiento de las funciones orofaciales. Su etiología es diversa y su recuperación, aunque generalmente favorable, depende en gran medida de una buena evaluación y rehabilitación realizada por un equipo multidisciplinar. Se trata de verificar la eficacia de las técnicas de intervención logopédica utilizadas en la parálisis facial y crear un protocolo de evaluación desde el punto de vista logopédico. Revisión bibliográfica para el estudio de las técnicas empleadas en la terapia de la parálisis facial. La evidencia científica de los estudios clínicos seleccionados ha sido revisada con la escala “Scottish Intercollegiate Guidelines Network” (SING). Revisión crítica de guías y protocolos de evaluación de los trastornos orofaciales y creación de un protocolo específico para evaluar la parálisis facial. Información valorativa de la eficacia de cada técnica rehabilitadora de la parálisis facial. Se muestra controversia con la electroterapia y el vendaje neuromuscular y resultados positivos en la masoterapia y los ejercicios faciales. Se crea y fundamenta el protocolo de evaluación de la parálisis facial. La rehabilitación logopédica de la parálisis facial periférica genera beneficios con técnicas como la masoterapia y los ejercicios mímicos. El vendaje neuromuscular no presenta resultados llamativos. La electroterapia se encuentra contraindicada en este tratamiento. El protocolo realizado ayuda a determinar las necesidades del sujeto. La función de la logopedia en la parálisis facial es importante para rehabilitar las alteraciones orofaciales y funcionales.Grado en Logopedi

Heuristic Evaluation of a Medical Device Prototype

Usability principles are often secondary to clinical effectiveness when assessing medical devices. However, the majority of medical device incidents are linked to user error. Greater attention to usability evaluation during the development of a medical device can prevent patient-endangering errors. In this study, the usability of a medical device prototype is assessed through heuristic evaluation. The aim was to carry out an evaluation and to assess heuristic evaluation as a method to improve medical device usability. The evaluated prototype is a mobile eye blink pacemaker aimed at patients with unilateral facial palsy. Facial palsy impairs the muscles responsible for producing the eye blink. Lack of blinking can result in complications such as dry eye disease and corneal ulceration. The purpose of the studied prototype is to evoke the eye blink with electrical stimulation. The device could be a simple and cost-effective alternative for more invasive methods. Heuristics targeted particularly for medical devices are yet to be developed. Heuristic applied in this study are a combination of heuristics formerly used in other studies analyzing medical devices. The majority of usability problems detected concerned the user’s control and physical effort. The most severe problems were related to error situations. Most of the heuristic violations were rated as minor problems; no catastrophic problems were found. The most problematic part of the prototype was the adjustment of the stimulation level. The heuristic evaluation is a quick and resource-efficient method to identify usability problems and their severities in medical devices. However, more research is needed to create a standard set of heuristics aimed especially at medical devices

Measurement of the N170 during facial neuromuscular electrical stimulation (fNMES).

Background Studies on facial feedback effects typically employ props or posed facial expressions, which often lack temporal precision and muscle specificity. New method Facial Neuromuscular Electrical Stimulation (fNMES) allows for a controlled influence of contractions of facial muscles, and may be used to advance our understanding of facial feedback effects, especially when combined with Electroencephalography (EEG). However, electrical stimulation introduces significant interference that can mask underlying brain dynamics. Whether established signal processing methods can allow for a reduction of said interference whilst retaining effects of interest, remains unexplored. Results We addressed these questions focusing on the classic N170 visual evoked potential, a face-sensitive brain component: 20 participants viewed images of houses, and of sad, happy, and neutral faces. On half of the trials, fNMES was delivered to bilateral lower-face muscles during the presentation of visual stimuli. A larger N170 amplitude was found for faces relative to houses. Interestingly, this was the case both without and during fNMES, regardless of whether the fNMES artefact was removed or not. Moreover, sad facial expressions elicited a larger N170 amplitude relative to neutral facial expressions, both with and without fNMES. Comparison with existing methods fNMES offers a more precise way of manipulating proprioceptive feedback from facial muscles, which affords greater diversity in experimental design for studies on facial feedback effects. Conclusions We show that the combining of fNMES and EEG can be achieved and may serve as a powerful means of exploring the impact of controlled proprioceptive inputs on various types of cognitive processing

Application of facial neuromuscular electrical stimulation (fNMES) in psychophysiological research: Practical recommendations based on a systematic review of the literature.

Facial neuromuscular electrical stimulation (fNMES), which allows for the non-invasive and physiologically sound activation of facial muscles, has great potential for investigating fundamental questions in psychology and neuroscience, such as the role of proprioceptive facial feedback in emotion induction and emotion recognition, and may serve for clinical applications, such as alleviating symptoms of depression. However, despite illustrious origins in the 19th-century work of Duchenne de Boulogne, the practical application of fNMES remains largely unknown to today's researchers in psychology. In addition, published studies vary dramatically in the stimulation parameters used, such as stimulation frequency, amplitude, duration, and electrode size, and in the way they reported them. Because fNMES parameters impact the comfort and safety of volunteers, as well as its physiological (and psychological) effects, it is of paramount importance to establish recommendations of good practice and to ensure studies can be better compared and integrated. Here, we provide an introduction to fNMES, systematically review the existing literature focusing on the stimulation parameters used, and offer recommendations on how to safely and reliably deliver fNMES and on how to report the fNMES parameters to allow better cross-study comparison. In addition, we provide a free webpage, to easily visualise fNMES parameters and verify their safety based on current density. As an example of a potential application, we focus on the use of fNMES for the investigation of the facial feedback hypothesis

Boosting brain–computer interfaces with functional electrical stimulation: potential applications in people with locked-in syndrome

Individuals with a locked-in state live with severe whole-body paralysis that limits their ability to communicate with family and loved ones. Recent advances in brain–computer interface (BCI) technology have presented a potential alternative for these people to communicate by detecting neural activity associated with attempted hand or speech movements and translating the decoded intended movements to a control signal for a computer. A technique that could potentially enrich the communication capacity of BCIs is functional electrical stimulation (FES) of paralyzed limbs and face to restore body and facial movements of paralyzed individuals, allowing to add body language and facial expression to communication BCI utterances. Here, we review the current state of the art of existing BCI and FES work in people with paralysis of body and face and propose that a combined BCI-FES approach, which has already proved successful in several applications in stroke and spinal cord injury, can provide a novel promising mode of communication for locked-in individuals

Facial Mimicry and the Processing of Facial Emotional Expressions

In social interactions, facial expressions make a major contribution to our daily communication as they can transmit internal states like motivations and feelings of our conspecifics. In the last decades, research has revealed that facial mimicry plays a pivotal role in the accurate perception and interpretation of facial expressions. Embodied simulation theories claim that facial expressions are automatically mimicked, thereby producing a facial feedback signal, which in turn activates a corresponding state in the motor, somatosensory, affective and reward system of the observer. This activation - in turn - facilitates the processing of the observed emotional expression and hence supports the understanding of its meaning. Research on the influence of facial mimicry on the perception of emotional expressions is, to a large extent, driven by facial mimicry manipulation studies. Especially the classical facial mimicry manipulation method introduced by Strack, Martin, and Stepper (1988) has become a popular and established method. Here participants have to hold a pen in different positions with the mouth inducing a smiling or a frowning expression. The present thesis assessed the influence of facial mimicry on cognitive processes by means of this classical facial mimicry manipulation method. In three projects, I investigated the impact of (1) facial mimicry on the automatic processing of facial emotional expressions, (2) facial mimicry on the working memory for emotional expressions, and (3) facial mimicry manipulation on an impaired processing of emotional expressions in patients with Parkinson’s disease (PD). In a first project, the impact of facial mimicry manipulation was measured by electrophysiological recordings of the expression related mismatch negativity to unattended happy and sad faces. The findings reveal that the automatic processing of facial emotional expressions is systematically influenced by facial mimicry. In the second project, I assessed the behavioral performance during a facial emotional working memory task while the mimicry of participants was manipulated. Findings of this project highlight that working memory for emotional expressions is influenced by facial mimicry. Finally, in the third project, I investigated the link between the reduced facial mimicry in PD patients and their impaired ability to recognize emotional expressions. For this purpose, I compared the data of PD and healthy individuals during the performance of an emotional change detection task while undergoing facial mimicry manipulation. Although healthy participants show a typical pattern of facial mimicry manipulation influence, PD patients do not profit of the applied manipulation. The results of the present thesis demonstrate that facial mimicry is an indispensable part in our daily social interaction as it affects the processing of emotions on a perceptual as well as a cognitive level. I showed that facial mimicry influences the automatic processing of - as well as the working memory for - observed facial emotional expressions. Furthermore, the empirical evidence of the third project suggests that not only facial mimicry is reduced in patients with PD but rather that the whole process of facial feedback processing is impaired in those individuals. These results demonstrate the applicability of the classical facial mimicry manipulation method and further highlight the importance of research on the influence of facial mimicry on cognitive processing as our ability to understand the emotional expressions of our conspecifics and thus our social interaction depends on an intact facial mimicry processing

Facial muscle activations by functional electrical stimulation

The present aim was to investigate transcutaneous facial muscle stimulation in order to take further steps in developing facial pacing technology, which can offer a new treatment option for patients with unilateral facial paralysis. This technology ultimately measures muscle activations from one side of the face and simultaneously activates the corresponding muscles of the other side with electrical stimulation. Four facial muscle locations—frontalis, orbicularis oculi, zygomaticus major, and orbicularis oris—of the healthy participants (N = 24) were stimulated to produce an eyebrow raise, eye blink, smile, and lip pucker, respectively. The results showed that a visually observable movement of the forehead and the lower lip was achieved in all participants. On average, the stimulations at the movement threshold were rated as tolerable in terms of pain ratings and neutral in terms of pleasantness ratings. Complete eye blink was achieved in 22 participants, and most did not experience painful sensations. The stimulation of the cheek evoked observable movement in 23 participants, but the stimulation also often resulted in concurrent activation of the eye, mouth, and nose area. The results suggest that transcutaneous stimulation seems to be a promising method for developing further facial pacing technology.publishedVersionPeer reviewe

A Spark Of Emotion: The Impact of Electrical Facial Muscle Activation on Emotional State and Affective Processing

Facial feedback, which involves the brain receiving information about the activation of facial muscles, has the potential to influence our emotional states and judgments. The extent to which this applies is still a matter of debate, particularly considering a failed replication of a seminal study. One factor contributing to the lack of replication in facial feedback effects may be the imprecise manipulation of facial muscle activity in terms of both degree and timing. To overcome these limitations, this thesis proposes a non-invasive method for inducing precise facial muscle contractions, called facial neuromuscular electrical stimulation (fNMES). I begin by presenting a systematic literature review that lays the groundwork for standardising the use of fNMES in psychological research, by evaluating its application in existing studies. This review highlights two issues, the lack of use of fNMES in psychology research and the lack of parameter reporting. I provide practical recommendations for researchers interested in implementing fNMES. Subsequently, I conducted an online experiment to investigate participants' willingness to participate in fNMES research. This experiment revealed that concerns over potential burns and involuntary muscle movements are significant deterrents to participation. Understanding these anxieties is critical for participant management and expectation setting. Subsequently, two laboratory studies are presented that investigated the facial FFH using fNMES. The first study showed that feelings of happiness and sadness, and changes in peripheral physiology, can be induced by stimulating corresponding facial muscles with 5–seconds of fNMES. The second experiment showed that fNMES-induced smiling alters the perception of ambiguous facial emotions, creating a bias towards happiness, and alters neural correlates of face processing, as measured with event-related potentials (ERPs). In summary, the thesis presents promising results for testing the facial feedback hypothesis with fNMES and provides practical guidelines and recommendations for researchers interested in using fNMES for psychological research