A system for delivering mechanical stimulation and robot-assisted therapy to the rat whisker pad during facial nerve regeneration

Artificial Intelligence-Based Facial Palsy Evaluation: A Survey

Facial palsy evaluation (FPE) aims to assess facial palsy severity of patients, which plays a vital role in facial functional treatment and rehabilitation. The traditional manners of FPE are based on subjective judgment by clinicians, which may ultimately depend on individual experience. Compared with subjective and manual evaluation, objective and automated evaluation using artificial intelligence (AI) has shown great promise in improving traditional manners and recently received significant attention. The motivation of this survey paper is mainly to provide a systemic review that would guide researchers in conducting their future research work and thus make automatic FPE applicable in real-life situations. In this survey, we comprehensively review the state-of-the-art development of AI-based FPE. First, we summarize the general pipeline of FPE systems with the related background introduction. Following this pipeline, we introduce the existing public databases and give the widely used objective evaluation metrics of FPE. In addition, the preprocessing methods in FPE are described. Then, we provide an overview of selected key publications from 2008 and summarize the state-of-the-art methods of FPE that are designed based on AI techniques. Finally, we extensively discuss the current research challenges faced by FPE and provide insights about potential future directions for advancing state-of-the-art research in this field.

Artificial Intelligence and Machine Learning in Neuroregeneration: A Systematic Review

Artificial intelligence (AI) and machine learning (ML) show promise in various medical domains, including medical imaging, precise diagnoses, and pharmaceutical research. In neuroscience and neurosurgery, AI/ML advancements enhance brain-computer interfaces, neuroprosthetics, and surgical planning. They are poised to revolutionize neuroregeneration by unraveling the nervous system's complexities. However, research on AI/ML in neuroregeneration is fragmented, necessitating a comprehensive review. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, 19 English-language papers focusing on AI/ML in neuroregeneration were selected from a total of 247. Two researchers independently conducted data extraction and quality assessment using the Mixed Methods Appraisal Tool (MMAT) 2018. Eight studies were deemed high quality, 10 moderate, and four low. Primary goals included diagnosing neurological disorders (35%), robotic rehabilitation (18%), and drug discovery (12% each). Methods ranged from analyzing imaging data (24%) to animal models (24%) and electronic health records (12%). Deep learning accounted for 41% of AI/ML techniques, while standard ML algorithms constituted 29%. The review underscores the growing interest in AI/ML for neuroregenerative medicine, with increasing publications. These technologies aid in diagnosing diseases and facilitating functional recovery through robotics and targeted stimulation. AI-driven drug discovery holds promise for identifying neuroregenerative therapies. Nonetheless, addressing existing limitations remains crucial in this rapidly evolving field.

Design of a high speed rat whiskers tracking and symmetry analysis system based on FPGA

This paper presents a high-speed rat whisker tracking and symmetry analysis system based on FPGA. The system utilizes high-speed image sensors recording rat face videos at 120 and 1000 fps. The Xilinx Ultra96 single computer board is chosen as the platform to implement the system's processing system (PS) and the programmable logic (PL) part. The PL part is responsible for high-speed image processing and whisker tracking, while the PS part analyzes the symmetry of rat face using the tracking results from the PL part. With a processing speed FoM of 118.5 fps/GHz on the Xilinx Ultra96 single computer board and 275.47 fps/GHz on a laptop with Intel Core i5-11500T@1.5GHz, the presented system achieves excellent performance. The proposed whisker detection method has a precision of 98.2% when a threshold with a 4-degree error is selected, with an average error angle of 0.98 degrees across more than 10,000 video frames. Moreover, the proposed system is capable of local video processing within millisecond delays. These results demonstrate the feasibility of developing a high-speed, accurate, and efficient whisker tracking and symmetry analysis system for rat behavior research.

Toward the Bionic Face: A Novel Neuroprosthetic Device Paradigm for Facial Reanimation Consisting of Neural Blockade and Functional Electrical Stimulation

BACKGROUND

Facial palsy is a devastating condition potentially amenable to rehabilitation by functional electrical stimulation. Herein, a novel paradigm for unilateral facial reanimation using an implantable neuroprosthetic device is proposed and its feasibility demonstrated in a live rodent model. The paradigm comprises use of healthy-side electromyographic activity as control inputs to a system whose outputs are neural stimuli to effect symmetric facial displacements. The vexing issue of suppressing undesirable activity resulting from aberrant neural regeneration (synkinesis) or nerve transfer procedures is addressed using proximal neural blockade.

METHODS

Epimysial and nerve cuff electrode arrays were implanted in the faces of Wistar rats. Stimuli were delivered to evoke blinks and whisks of various durations and amplitudes. The dynamic relation between electromyographic signals and facial displacements was modeled, and model predictions were compared against measured displacements. Optimal parameters to achieve facial nerve blockade by means of high-frequency alternating current were determined, and the safety of continuous delivery was assessed.

RESULTS

Electrode implantation was well tolerated. Blinks and whisks of tunable amplitudes and durations were evoked by controlled variation of neural stimuli parameters. Facial displacements predicted from electromyographic input modelling matched those observed with a variance-accounted-for exceeding 96 percent. Effective and reversible facial nerve blockade in awake behaving animals was achieved, without detrimental effect noted from long-term continual use.

CONCLUSIONS

Proof-of-principle of rehabilitation of hemifacial palsy by means of a neuroprosthetic device has been demonstrated. The use of proximal neural blockade coupled with distal functional electrical stimulation may have relevance to rehabilitation of other peripheral motor nerve deficits.

Whisking recovery after automated mechanical stimulation during facial nerve regeneration

IMPORTANCE Recovery from facial nerve transection is typically poor, but daily mechanical stimulation of the face in rats has been reported to remarkably enhance functional recovery after facial nerve transection and suture repair. This phenomenon needs additional investigation because of its important clinical implications. OBJECTIVE To determine whether automated mechanical stimulation of the whisker pad improves whisking recovery after facial nerve transection and repair in a rat model. DESIGN AND SETTING Sixty-one rats underwent unilateral facial nerve transection and suture repair and were randomized into 8 groups. Six groups received daily automated whisker or whisker pad mechanical stimulation including 0.5-, 1.5-, and 8.0-Hz patterns. Two control groups received restraint without stimulation. Treatment started on postoperative day 8, occurred 5 days per week, and lasted throughout 15 weeks of recovery. Whisking amplitude, velocity, and acceleration were quantified weekly for 15 weeks. INTERVENTIONS Unilateral facial nerve transection, suture repair, and, for 6 groups, daily automated whisker or whisker pad mechanical stimulation. MAIN OUTCOMES AND MEASURES Quantification of whisking amplitude, velocity, and acceleration. RESULTS Rats receiving the low frequencies of stimulation of the whiskers or whisker pad did not demonstrate enhanced whisking recovery, and rats receiving stimulation at 8.0 Hz showed significantly worse whisking recovery compared with controls and previously published groups receiving lower dose manual stimulation. CONCLUSIONS AND RELEVANCE Although daily manual whisker pad stimulation has been shown to enhance whisking recovery, rats in this study did not demonstrate improved whisking recovery after automated mechanical stimulation across a wide range of driving frequencies. Moreover, faster stimulation (8.0 Hz) was actually detrimental to recovery. Further work is needed to understand the relationship between stimulation patterns and the physiologic mechanisms underlying improved or worsened functional outcomes after facial nerve transection and repair.

Mediation of muscular control of rhinarial motility in rats by the nasal cartilaginous skeleton

The rhinarium is the rostral-most area of the snout that surrounds the nostrils, and is hairless in most mammals. In rodents, it participates in coordinated behaviors, active tactile sensing, and active olfactory sensing. In rats, the rhinarium is firmly connected to the nasal cartilages, and its motility is determined by movements of the rostral end of the nasal cartilaginous skeleton (NCS). Here, we demonstrate the nature of different cartilaginous regions that form the rhinarium and the nasofacial muscles that deform these regions during movements of the NCS. These muscles, together with the dorsal nasal cartilage that is described here, function as a rhinarial motor plant.