Blink Research Articles

Unsupervised Learning of Eye State Prototypes for Semantically Rich Blinking Detection.

Blinking contributes to the health and protection of the eye and also holds potential in the context of muscle or nerve disorder diagnosis. Traditional methods of classifying eye blinking as open or closed are insufficient, as they do not capture medical-relevant aspects like closure speed, duration, or percentage. The issue could be solved by reliably detecting blinking intervals in high-temporal recordings. Our research demonstrates the reliable detection of blinking events through data-driven analysis of the eye aspect ratio. In an unsupervised manner, we establish an eye state prototype to identify blink intervals and measure inter-eye synchronicity between moments of peak closure. Additionally, our research shows that manually defined prototypes yield comparable results. Our results demonstrate inter-eye synchronicity up to 4.16 ms. We anticipate that medical professionals could utilize our methods to identify or define disease-specific prototypes as potential diagnostic tools.

Oculomotor behaviors in youth with an eating disorder: findings from a video-based eye tracking task

BackgroundThe oculomotor circuit spans many cortical and subcortical areas that have been implicated in psychiatric disease. This, combined with previous findings, suggests that eye tracking may be a useful method to investigate eating disorders. Therefore, this study aimed to assess oculomotor behaviors in youth with and without an eating disorder.MethodsFemale youth with and without an eating disorder completed a structured task involving randomly interleaved pro-saccade (toward at a stimulus) and anti-saccade (away from stimulus) trials with video-based eye tracking. Differences in saccades (rapid eye movements between two points), eye blinks and pupil were examined.ResultsYouth with an eating disorder (n = 65, Mage = 17.16 ± 3.5 years) were compared to healthy controls (HC; n = 65, Mage = 17.88 ± 4.3 years). The eating disorder group was composed of individuals with anorexia nervosa (n = 49), bulimia nervosa (n = 7) and other specified feeding or eating disorder (n = 9). The eating disorder group was further divided into two subgroups: individuals with a restrictive spectrum eating disorder (ED-R; n = 43) or a bulimic spectrum eating disorder (ED-BP; n = 22). In pro-saccade trials, the eating disorder group made significantly more fixation breaks than HCs (F(1,128) = 5.33, p = 0.023). The ED-BP group made the most anticipatory pro-saccades, followed by ED-R, then HCs (F(2,127) = 3.38, p = 0.037). Groups did not differ on rate of correct express or regular latency pro-saccades. In anti-saccade trials, groups only significantly differed on percentage of direction errors corrected (F(2, 127) = 4.554, p = 0.012). The eating disorder group had a significantly smaller baseline pupil size (F(2,127) = 3.60, p = 0.030) and slower pro-saccade dilation velocity (F(2,127) = 3.30, p = 0.040) compared to HCs. The ED-R group had the lowest blink probability during the intertrial interval (ITI), followed by ED-BP, with HCs having the highest ITI blink probability (F(2,125) = 3.63, p = 0.029).ConclusionsThese results suggest that youth with an eating disorder may have different oculomotor behaviors during a structured eye tracking task. The oculomotor behavioral differences observed in this study presents an important step towards identifying neurobiological and cognitive contributions towards eating disorders.

Spontaneous eye blinks in horses (Equus caballus) are modulated by attention

Spontaneous eye blinks are brief closures of both eyelids. The spontaneous eye blink rate (SEBR) exceeds physiological corneal needs and is modulated by emotions and cognitive states, including vigilance and attention, in humans. In several animal species, the SEBR is modulated by stress and antipredator vigilance, which may limit the loss of visual information due to spontaneous eye closing. Here, we investigated whether the SEBR is modulated by attention in the domestic horse (Equus caballus). Our data supported previous studies indicating a tonic SEBR specific to each individual. We also found that, superimposed on a tonic SEBR, phasic changes were induced by cognitive processing. Attention downmodulated the SEBR, with the magnitude of blink inhibition proportional to the degree of attentional selectivity. On the other hand, reward anticipation upregulated the SEBR. Our data also suggested that horses possess the cognitive property of object permanence: they understand that an object that is no longer in their visual field has not ceased to exist. In conclusion, our results suggested that spontaneous eye blinks in horses are modulated by attentional cognitive processing.

Immunojanus Particles for low-volume and isolation-free unlabeled characterization of small Extracellular Vesicle in biofluids: Characterization of disease type by surface marker profiling.

Small extracellular vesicles (sEVs) are vital for cellular communication and serve as critical biomarker carriers for diseases such as cancer. However, quantifying and profiling sEV surface markers presents significant challenges due to the low concentration of specific sEV-bound proteins and interference by more abundant dispersed proteins. This paper presents Immunojanus Particles (IJPs), a new method that enables the direct detection of sEVs in less than an hour without isolation. The design of IJPs incorporates fluorescent and non-fluorescent halves, utilizing rotational Brownian motion to detect captured sEVs through the change in the blinking rate, without interference from the smaller dispersed proteins. We demonstrate a detection limit of 2E5 sEVs/mL with low sample volumes and the capability to characterize sEVs directly from plasma, serum, cell culture media, and urine. In a small pilot study involving 87 subjects, including individuals with colorectal cancer, pancreatic ductal adenocarcinoma, glioblastoma, Alzheimer's disease, and healthy controls, our method accurately identified the type of disease with high 0.90-0.99 AUC in a blind setting. Compared with an orthogonal ultracentrifugation plus surface plasmon resonance (UC+SPR) method that requires about 24 hours, the sensitivity and dynamic range of IJP are better by 2 logs.

Vestibular prepulse inhibition of the human blink reflex

ObjectiveAuditory and somatosensory prepulses are commonly used to assess prepulse inhibition (PPI). The effect of a vestibular prepulse upon blink reflex excitability has not been hitherto assessed. MethodsTwenty-two healthy subjects and two patients with bilateral peripheral vestibular failure took part in the study. Whole body yaw rotation in the dark provided a vestibular inertial prepulse. Blink reflex was electrically evoked after the end of the rotation. The amplitude of R1 and the area-under-the-curve (area) of the blink reflex R2 and R2c responses were recorded and analysed. ResultsA vestibular prepulse inhibited the R2 (p < 0.001) and R2c area (p < 0.05). Increasing the angular acceleration did not increase the R2 and R2c inhibition (p > 0.05). Voluntary suppression of the vestibulo-ocular reflex did not affect the magnitude of inhibition (p > 0.05). Patients with peripheral vestibular failure did not show any inhibition. ConclusionsOur data support a vestibular gating mechanism in humans. SignificanceThe main brainstem nucleus mediating PPI – the pedunculopontine nucleus (PPN) – is heavily vestibular responsive, which is consistent with our findings of a vestibular-mediated PPI. Our technique may be used to interrogate the fidelity of brain circuits mediating vestibular-related PPN functions. Given the PPN’s importance in human postural control, our technique may also provide a neurophysiological biomarker of balance.

Clinical and electrophysiological prognostic factors in predicting poor outcomes in patients with idiopathic facial nerve paralysis

ObjectiveThis study was designed to verify whether one or more clinical and neurophysiological parameters could predict a poor prognosis in idiopathic facial paralysis. MethodsSeventy-three outpatients with unilateral idiopathic facial nerve paralysis who visited our hospital within 7 days of onset. All patients received treatment according to a standard therapy protocol and ocular care. Patients’ baseline characteristics were assessed before initiating treatment, including demographic characteristics, facial nerve function assessment and previous medical history. House-Brackmann (H-B) grading system was performed at baseline and six months after the onset. Electroneurography (ENoG) and blink reflex tests were conducted 7–10 days after the onset of paralysis. Sunnybrook Facial Grading System (SFGS) was conducted at baseline, days 7–10 post-onset when the electrophysiological tests were performed, and one month after the onset. ResultsAccording to the H-B grade at 6 months following the onset, 58 patients (79.5 %) had a good prognosis, while 15 patients (20.5 %) had a poor prognosis. The CMAP amplitudes in three facial muscles (frontalis, orbicularis oculi, and orbicularis oris) were decreased, and ENoG values were increased in the poor prognosis group compared with the good prognosis group (all p < 0.01). The results of the blink reflex study showed that the group with a poor prognosis had a longer R1 latency compared to the group with a good prognosis. Additionally, the group with a poor prognosis exhibited a higher rate of R1 absence on the affected side (both p < 0.01). The findings of conditional logistic regression indicated that the absence of R1 on the affected side, frontalis ENoG, orbicularis oculi ENoG, and orbicularis oris ENoG were predictive factors of a poor prognosis for facial nerve palsy. The receiver operating characteristic (ROC) curves showed that the SFGS at 1 month after onset of 55 is considered a critical cutoff value for poor prognosis, with a sensitivity of 86.7 % and specificity of 91.4 %. ConclusionElectroneurography (ENoG) and blink reflex tests acquired within 7–10 days after the onset of paralysis are significant and highly valuable for predicting the prognosis of idiopathic facial nerve paralysis. Higher ENoG values of the muscles innervated by the facial nerve and the absence of R1 on the affected side of the blink reflex are predictive factors for a poor prognosis. The SFGS is a clinical tool that plays an important role in evaluating the prognosis of idiopathic facial paralysis, particularly one month after onset.

PaFESD: Patterns augmented by Features Epileptic Seizure Detection.

The detection of epileptic seizures can have a significant impact on the patients' quality of life and on their caregivers. In this paper we propose a method for detecting such seizures from electroencephalogram (EEG) data named Patterns augmented by Features Epileptic Seizure Detection (PaFESD). The main novelty of our proposal consists in a detection model that combines EEG signal features with pattern matching. After cleaning the signal and removing artifacts (as eye blinking or muscle movement noise), time-domain and frequency-domain features are extracted to filter out non-seizure regions of the EEG. Jointly, pattern matching based on Dynamic Time Warping (DTW) distance is also leveraged to identify the most discriminative patterns of the seizures, even under scarce training data. The proposed model is evaluated on all patients in the CHB-MIT database, and the results show that it is able to detect seizures with an average F1 score of 98.9%. Furthermore, our approach achieves a F1 score of 100% (no false alarms or missed true seizures) for 20 of the patients (out of 24). Additionally, we automatically detect the most seizure/non-seizure discriminative EEG channel so that a wearable with only two electrodes would suffice to warn patients of seizures.

Blink-induced changes in pupil dynamics are consistent and heritable.

Pupil size and blink rates are heritable but the extent to which they interact with one another has not been properly investigated. Though changes in pupil size due to eye blinks have been reported, they are considered a pupillary artifact. In this study we used the HCP 7T fMRI dataset with resting state eye-tracking data obtained in monozygous and dizygous twins to assess their heritability and their interactions. For this purpose, we characterized the pupil dilation (positive peak) and constriction (negative peak) that followed blink events, which we describe as blink-induced pupillary response (BIPR). We show that the BIPR is highly consistent with a positive dilatory peak (D-peak) around 500ms and a negative constricting peak (C-peak) around 1s. These patterns were reproducible within- and between- subjects across two time points and differed by vigilance state (vigilant versus drowsy). By comparing BIPR between monozygous and dizygous twins we show that BIPR have a heritable component with significant additive genetic (A) and environmental (E) factors dominating the structural equation models, particularly in the time-domain for both D- and C-peaks and amplitude domain for the C-peak. (a2 between 42-49%). Blink duration, pupil size and blink rate were also found to be highly heritable (a2 up to 62% for pupil size). Our study documents an association between BIPR and wakefulness and indicates that BIPR should not be treated as a coincidental artefact, but part of a larger oculomotor system that we label here as Oculomotor Adaptive System, OAS, that is genetically determined.

Transcranial alternating current stimulation can modulate the blink reflex excitability. Effects of a 10- and 20-Hz tACS session on the blink reflex recovery cycle in healthy subjects.

The blink reflex excitability, assessed through paired electrical stimuli responses, has been modulated using traditional non-invasive neurostimulation techniques. Recently, transcranial Alternating Current Stimulation (tACS) emerged as a tool to modulate brain oscillations implicated in various motor, perceptual, and cognitive functions. This study aims to investigate the influence of 20-Hz and 10-Hz tACS sessions on the primary motor cortex and their impact on blink reflex excitability. Fifteen healthy volunteers underwent 10-min tACS sessions (intensity 1mA) with active/reference electrodes placed over C4/Pz, delivering 20-Hz, 10-Hz, and sham stimulation. The blink reflex recovery cycle (BRrc) was assessed using the R2 amplitude ratio at various interstimulus intervals (ISIs) before (T0), immediately after (T1), and 30min post-tACS (T2). Both 10-Hz and 20-Hz tACS sessions significantly increased R2 ratio at T1 (10-Hz: p = 0.02; 20-Hz: p < 0.001) and T2 (10-Hz: p = 0.01; 20-Hz: p < 0.001) compared to baseline (T0). Notably, 20-Hz tACS induced a significantly greater increase in blink reflex excitability compared to sham at both T1 (p = 0.04) and T2 (p < 0.001). This study demonstrates the modulatory effect of tACS on trigemino-facial reflex circuits, with a lasting impact on BRrc. Beta-band frequency tACS exhibited a more pronounced effect than alpha-band frequency, highlighting the influential role of beta-band oscillations in the motor cortex on blink reflex excitability modulation.

Automated analysis of spontaneous eye blinking in patients with acute facial palsy or facial synkinesis

Although patients with facial palsy often complain of disturbed eye blinking which may lead to visual impairment, a blinking analysis is not part of routine grading of facial palsy. Twenty minutes of spontaneous eye blinking at rest of 30 patients with facial palsy (6 with acute palsy; 24 patients with facial synkinesis; median age: 58 years, 67% female), and 30 matched healthy probands (median age: 57 years; 67% female) was smart phone video recorded. A custom computer program automatically extracted eye measures and determined the eye closure rate (eye aspect ratio [EAR]), blink frequency, and blink duration. Facial Clinimetric Evaluation (FaCE), Facial Disability Index (FDI) were assessed as patient-reported outcome measures. The minimal EAR, i.e., minimal visible eye surface during blinking, was significantly higher on the paretic side in patients with acute facial palsy than in patients with synkinesis or in healthy controls. The blinking frequency on the affected side was significantly lower in both patient groups compared to healthy controls. Vice versa, blink duration was longer in both patient groups. There was no clear correlation between the blinking values and FaCE and FDI. Blinking parameters are easy to estimate automatically and add a functionally important parameter to facial grading.

Treatment of hemihydranencephaly in a cat with ventriculoperitoneal shunt

Hemihydranencephaly is extremely rare in cats. In this case report, the aim is to share data on the diagnosis and treatment of a hemihydranencephaly in a cat. This case report is for an 1 year old, 3 kg, male, Scottish fold cat. The cat was brought in by its owner with behavioural changes and decreased activity since birth. Cranial nerve examination revealed that threat reflex and lateral palpebral reflex were decreased and corneal reflex was delayed. Spinal reflex examination revealed a decreased patellar reflex and proprioceptive deficit in all extremities in the postural reaction test. As a result of the tests, a cranial lesion was suspected. Magnetic resonance imaging revealed that the right cerebral hemisphere and ependyma were absent and instead were filled with fluid. In light of the findings, the patient was diagnosed with a hemihydranencephaly. Furosemide, and prednisone were used for medical treatment. However, despite a week of medical treatment, no improvement was observed. Ventriculoperitoneal shunt placement was preferred as the surgical method. Although all of the patient's neurological findings did not disappear in the postoperative period, they improved. A cat with haemihydraocephaly was successfully treated with ventriculoperitoneal shunt for the first time.

Clinical Effect of Combined Fascia Sheath Suspension With Shortening Levator Muscle on Severe Blepharoptosis.

To study the clinical effect of conjoint fascial sheath (CFS) suspension and levator palpebrae superioris muscle shortening in the treatment of severe blepharoptosis. Forty-five patients with severe blepharoptosis (75 eyes) from May 2020 to February 2022 in the authors' hospital were divided into 2 groups: group A (n = 33, 43 eyes) and group B (n = 24, 32 eyes). Group A was operated on by CFS + levator muscle shortening, and group B was operated on by frontal muscle flap suspension + levator muscle shortening. Both groups were followed up for 12 months (until February 2023). The clinical effect was counted in 6 months after operation, the early complications were counted in 1 month after operation, and the late complications were counted in 1 month to 12 months after operation. Margin to corneal reflex distance 1 (MRD1) and palpebral fissure height (PFH) were recorded before, 1 week, 3 months, and 12 months postoperatively, and the amount of eyelid retrogression was counted again. The good correction rate was 90.70% in group A, higher than in group B (71.88%), and the difference was statistically significant (P< 0.05); the early postoperative complication rate was 9.30%, lower than in group B (24.38%), and the difference was statistically significant (P< 0.05); the late postoperative complication rate was 2.33%, lower than group B (18.75%), and the difference was statistically significant (P< 0.05). The MRD1 and PFH of group A were higher than those of group B (P< 0.05) at 3 months postoperatively and 12 months postoperatively; the MRD1 and PFH of group A were lower than those of group B (P< 0.05) at 3 months postoperatively and 12 months postoperatively. Repeated measurement analysis of variance showed that there were significant differences in the main effects of MRD1, PFH, eyelid retrogression, and time in group A and group B (P< 0.05), and there was interaction between intervention and time (P< 0.05). Conjoint fascial sheath suspension combined with levator palpebrae superioris muscle shortening can effectively improve MRD1 and PFH, and the amount of upper eyelid retraction is controllable 1 year after operation.

Accident Prevention System

Accident prevention system represents a groundbreaking innovation in vehicular safety technology. This advanced system integrates cutting- edge technologies such as eye blink sensors, GPS modules, Arduino and GSM communication to detect and mitigate potential hazards during driving. The accident prevention system incorporates a GPS module, enabling precise location tracking and providing crucial data for emergency responders. The integration of these technologies aims to significantly reduce the risk of accidents caused by driver inattention, fatigue, or other safety-critical factors. This abstract outline the comprehensive approach of accident prevention system, highlighting its potential to revolutionize road safety by leveraging state-of-the-art sensor technologies and intelligent communication systems. Key Words: Eye blink sensor, Arduino, GPS Module, GSM Module.

Investigating the influence of eye-catching effect on mental workload in highway tunnel entrances: a comprehensive analysis of eye blink behavior

Objective The objective of this study was to investigate the relationship between eye-catching effects and mental workload at highway tunnel entrances. Specifically, the study aimed to analyze drivers’ eye blink behavior to gain a comprehensive understanding of how visual attraction at tunnel entrances affects cognitive workload. Methods 50 participants were recruited for the naturalistic driving experiment. Four different visually attractive driving scenarios (baseline, landscape-style architecture, tip slogan, and billboard) were selected. Eye-tracking technology was utilized to record and analyze the eye blink behavior of participating drivers. Various metrics, including blink frequency, blink duration, inter-blink interval, and pupil diameter after a blink, were measured and compared across different scenarios. Results The results of the study demonstrated significant differences in drivers’ eye blink behavior across the different experimental scenarios, indicating the influence of visual attraction conditions on mental workload. The presence of eye-catching stimuli (landscape-style architecture, tip slogan, and billboard scenarios) at tunnel entrances resulted in decreased blink frequency, shorter blink duration, longer inter-blink intervals, and larger pupil diameter after a blink compared to when no specific eye-catching stimuli were present (baseline condition). These findings suggest that visual attractions capture drivers’ attention, leading to increased cognitive workload and attentional demands. Conclusions The findings of this study contribute to the existing literature on driver attention and mental workload, particularly in relation to eye-catching effect in tunnel environments. The presence of eye-catching stimuli at tunnel entrances can distract drivers and increase their mental workload, potentially compromising driving performance and safety. It is crucial for transportation authorities and designers to carefully consider the design and placement of visual attractions in tunnel entrances to minimize distraction and cognitive workload. By doing so, driving safety and performance can be enhanced in tunnel entrances.

Interpreting the latent space of a Convolutional Variational Autoencoder for semi-automated eye blink artefact detection in EEG signals

Electroencephalography (EEG) allows the investigation of brain activity. However, neural signals often contain artefacts, hindering signal analysis. For example, eye-blink artefacts are particularly challenging due to their frequency overlap with neural signals. Artificial intelligence, particularly Variational Autoencoders (VAE), has shown promise in EEG artefact removal. This research explores the design and application of Convolutional VAEs for automatically detecting and removing eye blinks in EEG signals. The latent space of CVAE, trained on EEG topographic maps, is used to identify latent components that are selective for eye blinks. Receiver Operating Characteristic (ROC) curves and Area Under the Curve (AUC) are employed to evaluate the discriminative performance of each latent component. The most discriminative component, determined by the highest AUC, is modified to eliminate eye blinks. The evaluation of artefact removal involves visual inspection and Pearson correlation index assessment of the original EEG signal and the reconstructed clean version, focusing on the Fp1 and Fp2 channels most affected by eye-blink artefacts. Results indicate that the proposed method effectively removes eye blinks without significant loss of information related to the neural signal, demonstrating Pearson correlation values around 0.60 for each subject. The contribution to the knowledge offered by this research study is the design and application of a novel offline pipeline for automatically detecting and removing eye blinks from multi-variate EEG signals without human intervention.

Rapid Voluntary Blinking as a Clinical Marker of Parkinson's Disease.

Reduced spontaneous blinking is a recognized Parkinson's disease (PD) feature. In contrast, voluntary blinking has been less studied and might serve as a measurable marker of facial bradykinesia. We tested 31 PD patients and 31 controls. Participants were filmed during conversation and a rapid blinking task. Both tasks were videorecorded to count the number of blinks per second. PD patients had lower blink rates. Rapid blinking accurately discriminated between groups with 77% sensitivity and 71% specificity. To conclude, rapid blinking may be a simple and quantifiable task of facial bradykinesia.

Dynamic Eye Closure Restoration in Facial Palsy with Neurotized Platysma Muscle Graft in Rats.

One of the most devastating deficits of facial paralysis is eyelid dysfunction, which is controlled by the orbicularis oculi muscle (OOM), as it leads to loss of the protective mechanism of the eye. This study used a rat model to assess the functional outcomes of neurotized platysma muscle grafts (PMGs) for OOM replacement. Forty male Sprague-Dawley rats with iatrogenic right eyelid dysfunction were divided into five groups: one control group and four groups utilizing PMG with different sources of nerve innervation. Eyelid function recovery was assessed at 2, 4, 6, and 8 weeks. The PMGs were harvested for pathological examination at the end of the study. All rats except those in the control group and one from the group using ipsilateral frontal and upper zygomatic frontal nerve branches directly neurotized to the PMG (nerve-to-muscle) recovered eyelid closure function within 8 weeks of the study period. The mean recovery time was 3.87 ± 1.28 weeks. A total of 87.5% of rats that had the contralateral zygomatic branch as the donor nerve regained the consensual corneal reflex (p-value < 0.001). Replacement of neurotized PMG for OOM function is successful in a rat model. Using the upper zygomatic branch as the donor nerve, it was possible to restore the consensual corneal reflex. This method shows promise for further human studies.

Modulation of the somatosensory blink reflex under fear

ObjectiveThis study evaluated the isolated and combined effects of fear and PPS paradigms on SBR. MethodThe prospective study was conducted with healthy participants. After stimulation of the right median nerve at the wrist, bilateral recordings were randomized under the following conditions: First experiment (with the right hand on the chair armrest): i. baseline recordings, ii. while watching fearful facial expressions from the Karolinska Emotional Faces battery (fear), iii. post-watching (post-fear), iv. while watching neutral facial expressions from the same battery (neutral), v. Immediately after viewing (post-neutral). Second experiment (right hand 2 cm away from the right eye, PPS): i. reference condition (PPS), ii. while watching fearful facial expressions (PPS-fear), iii. while watching neutral facial expressions (PPS-neutral). In each condition, SBR latency, area, duration, and amplitudes were measured and compared between conditions. ResultsWe included 16 participants. SBR could be recorded in 11 (mean age:30.7 ± 5.2, F/M:5/6). First experiment: SBR amplitude was significantly reduced in fear condition (p = 0.008), and SBR area was reduced considerably in fear and post-fear conditions (p = 0.004) compared to the baseline. Second experiment: The SBR area was higher in the PPS (p = 0.009) compared to the baseline and even higher in the fearPPS compared to the PPS (p = 0.038). In neutral or PPS-neutral conditions, the area of the SBR did not change significantly. ConclusionFear suppressed SBR, but fear increased SBR when a threat stimulus was present. The findings were unrelated to habituation or attention, indicating cortical-amygdala-bulbar connections.

Gamma Knife radiosurgery for multiple sclerosis-associated trigeminal neuralgia

BackgroundGamma Knife radiosurgery (GKRS) has well-known efficacy in the treatment of idiopathic trigeminal neuralgia (TN). However, few studies have evaluated the effects of GKRS in the treatment of multiple sclerosis (MS)-related TN. This study analyzed the efficacy and complications of GKRS for MS-related TN. MethodsThis retrospective study included 28 MS-related TN patients who underwent GKRS with a median follow-up of 27 (range, 12–181) months. The cisternal segment of the trigeminal nerve was targeted with a median radiation dose of 80 (80–90) Gy. Pain intensity was assessed using Barrow Neurological Institute (BNI)-Pain Intensity Scores (BNI-PIS). Before GKRS, all patients suffered from BNI pain levels of 4 or 5. A reduction in pain to BNI 3b or below was deemed as adequate pain relief. ResultsThe initial proportion of patients who experienced adequate pain relief was 71.4%, with a median interval of 21 (1–45) days. At the final follow-up, 50% of patients had achieved adequate pain relief. Ten patients (35.7%) suffered from complications, including four with facial sensorial dysfunctions, four with a decline in their corneal reflexes, and two with jaw weakness. Among the 20 initial responders, six (30%) patients suffered pain recurrence after a median interval of 35 (12–180) months. ConclusionsGKRS is an effective means of pain relief in MS-related TN, but has side effects that are relevant to other ablative treatments. The benefits and risks of GKRS should be discussed with patients who wish to avoid surgery or when previous treatments fail.

A Prediction Rule for the Dystonic Spread of Blepharospasm: A 4-Year Prospective Cohort Study.

Blepharospasm (BSP), focal dystonia with the highest risk of spread, lacks clear understanding of early spreading risk factors and objective prognostic indicators. We aimed to identify these risk factors through clinical and electrophysiological assessments, and to establish a predictive model for dystonic spread in BSP. We prospectively followed BSP patients for 4 years, collecting data on dystonic spread, and conducting electrophysiological evaluations. The blink reflex, masseter inhibitory reflex, and trigeminal somatosensory evoked potential were assessed. Univariable and multivariable Cox proportional hazard regression models were used to assess clinical characteristics associated with BSP dystonic spread. A predictive model was constructed using a nomogram, and performance of the model was evaluated using the area under the receiver operating characteristic curve. A total of 136 enrolled participants (mean age 56.34 years) completed a 4-year follow-up. Among them, 62 patients (45.6%) showed spread to other body regions. Multivariable Cox regression analysis showed that a high Hamilton Anxiety Scale score (hazard ratio 1.19, 95% confidence interval 1.13-1.25, p < 0.001), prolonged trigeminal somatosensory evoked potential mandibular branch P1-N2 peak interval (hazard ratio 1.11, 95% confidence interval 1.02-1.21, p = 0.017), and elevated trigeminal somatosensory evoked potential mandibular branch P1-N2 peak amplitude (hazard ratio 1.26, 95% confidence interval 1.12-1.41, p < 0.001) were independent risk factors for BSP dystonic spread within 4 years. Combining these factors, the predictive models demonstrated excellent discriminative ability, with the receiver operating characteristic curve score being 0.797, 0.790, 0.847, and 0.820 at 1, 2, 3 and 4 years after enrollment, respectively. We established a predictive model with significant value for anticipating dystonic spread in BSP, offering crucial evidence. These findings contribute essential insights into the early clinical identification of the development and evolution of BSP diseases. ANN NEUROL 2024;96:747-757.