Locked-in syndrome after central pontine myelinolysis, an outstanding outcome of two patients

OBJECTIVE

Central pontine myelinolysis (CPM) is a rare demyelinating disease that affects the pons and which can cause extreme disabilities such as locked-in syndrome (LIS) in the initial phase. The aim of the study was to describe the evolution over a 12-month period of two patients with CPM causing an initial LIS.

METHOD

We retrospectively report the unexpected clinical outcome of these two patients in relation with the anatomical damages documented by brain MRI, associated with diffusion tensor imaging and reconstruction of corticospinal tracts in tractography. The following clinical parameters systematically assessed at 3, 6, 9, and 12 months: muscle testing on 12 key muscles (Medical Research Council), prehension metrics (box and block test and purdue pegboard), and independence for acts of daily living (functional independence measure).

RESULTS

Both patients showed a progressive recovery beginning between 2 and 3 months after the onset of symptoms, leading to almost complete autonomy at 12 months (FIM > 110), with motor strength greater than 4/5 in all joint segments (MRC > 50/60). On brain MRI with tractography, CST appeared partially preserved at pons level.

INTERPRETATION

The possibility of a near-complete functional recovery at 12 months is important to consider given the ethical issues at stake and the discussions about limiting care that may take place initially. It seems to be the consequence of reversible myelin damage combined with partially preserved neurons. Development of collateral pathways or resolution of conduction block may explain this recovery. MRI comprising DTI and tractography could play a key role in the prognosis of motor recovery.

Brain-Computer Interfaces, Completely Locked-In State in Neurodegenerative Diseases, and End-of-Life Decisions

In the future, policies surrounding end-of-life decisions will be faced with the question of whether competent people in a completely locked-in state should be enabled to make end-of-life decisions via brain-computer interfaces (BCI). This article raises ethical issues with acting through BCIs in the context of these decisions, specifically self-administration requirements within assisted suicide policies. We argue that enabling patients to end their life even once they have entered completely locked-in state might, paradoxically, prolong and uphold their quality of life.

Anesthetic Considerations for Patients with Locked-In Syndrome Undergoing Endoscopic Procedures

BACKGROUND Delivering safe anesthetic care to a patient unable to communicate easily and effectively with the anesthesia team presents many unique challenges. Communication may be limited by language, which can be resolved with translation services, or neurological conditions, such as stroke or traumatic brain injury, which are not easily remedied. In such patients, the inability to communicate effectively can lead to anxiety and negatively impact the patient-anesthesiologist relationship, especially when higher cognitive functions are preserved. CASE REPORT We present a case of a patient with locked-in syndrome (LIS), who presented to our endoscopy unit for a routine colonoscopy. The patient could only communicate with eye movements and blinking, thus limiting our ability to assess their pain or other needs in the perioperative period; however, she was otherwise cognitively intact. By utilizing the patient's home healthcare team and quickly adapting their unique communication methods during the perioperative period, we were able to provide an appropriate, safe anesthetic for this patient with LIS. CONCLUSIONS Many patients requiring an anesthetic are unable to effectively communicate due to language issues, hearing loss/mutism, neurological injury/stroke (aphasia), or developmental disabilities. The unique communication needs of this patient with LIS went beyond utilizing a translator and required the healthcare team to quickly learn a new communication method. We also discuss forms of intraoperative monitoring that can be used to differentiate consciousness from the anesthetized state in LIS patients, as well as making recommendations for future care of such patients.

The challenge of controlling an auditory BCI in the case of severe motor disability

BACKGROUND

The locked-in syndrome (LIS), due to a lesion in the pons, impedes communication. This situation can also be met after some severe brain injury or in advanced Amyotrophic Lateral Sclerosis (ALS). In the most severe condition, the persons cannot communicate at all because of a complete oculomotor paralysis (Complete LIS or CLIS). This even prevents the detection of consciousness. Some studies suggest that auditory brain-computer interface (BCI) could restore a communication through a « yes-no» code.

METHODS

We developed an auditory EEG-based interface which makes use of voluntary modulations of attention, to restore a yes-no communication code in non-responding persons. This binary BCI uses repeated speech sounds (alternating "yes" on the right ear and "no" on the left ear) corresponding to either frequent (short) or rare (long) stimuli. Users are instructed to pay attention to the relevant stimuli only. We tested this BCI with 18 healthy subjects, and 7 people with severe motor disability (3 "classical" persons with locked-in syndrome and 4 persons with ALS).

RESULTS

We report online BCI performance and offline event-related potential analysis. On average in healthy subjects, online BCI accuracy reached 86% based on 50 questions. Only one out of 18 subjects could not perform above chance level. Ten subjects had an accuracy above 90%. However, most patients could not produce online performance above chance level, except for two people with ALS who obtained 100% accuracy. We report individual event-related potentials and their modulation by attention. In addition to the classical P3b, we observed a signature of sustained attention on responses to frequent sounds, but in healthy subjects and patients with good BCI control only.

CONCLUSIONS

Auditory BCI can be very well controlled by healthy subjects, but it is not a guarantee that it can be readily used by the target population of persons in LIS or CLIS. A conclusion that is supported by a few previous findings in BCI and should now trigger research to assess the reasons of such a gap in order to propose new and efficient solutions.

CLINICAL TRIAL REGISTRATIONS

No. NCT02567201 (2015) and NCT03233282 (2013).

[Listeria meningoencephalitis resulting in complete bilateral ophtalmoplegia and locked-in syndrome]

This is a description of the case of quite severe neurolisteriosis in an adult man resulting in the rare combination of neurological symptoms such as complete bilateral ophtalmoplegia and locked-in syndrome. The case illustrates clinical features that are special for this disorder and also highlights management of such patients.

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.

Demographic, Medical, and Clinical Characteristics of a Population-Based Sample of Patients With Long-lasting Locked-In Syndrome

BACKGROUND AND OBJECTIVES

Patients with classic locked-in syndrome (LIS), typically caused by ventral pontine stroke, present with quadriplegia, mutism, intact consciousness, and communication skills limited to vertical gazing and/or blinking. Clinical presentations and definitions of LIS differ, especially regarding incomplete LIS. In our study, we explored the functional diversity of LIS, its outcomes, and the complexity of its course along with variations in the location of lesions and their potential significance for outcomes.

METHODS

A national cohort of patients with vascular LIS who remained in the LIS state for at least 6 weeks according to a functional definition of LIS was studied. Demographic, medical, and follow-up data, collected between 2012 and 2022, were obtained from the quality register of the Norwegian National Unit for Rehabilitation of Locked-In Syndrome. Outcomes in verbal communication, motor function, and dependency were evaluated according to criteria for being in or not in the LIS state. The modified Rankin scale and LIS motor recovery scale were applied. Descriptive analysis was performed. The relationship between lesion location and functional outcome was investigated.

RESULTS

The sample included 51 patients (median age: 55.7 years, 36 male individuals), 43 of whom had follow-up data. Ischemic stroke was the most common etiology (n = 35). Twenty-three patients had emerged from the LIS state, mostly within 2 years after onset. All but 1 patient achieved some motor improvement, whereas only 3 achieved full motor recovery, and 88% had a persistently high level of dependence. The 3-year survival rate was 87%. Five patients had an isolated pontine lesion, whereas 80% showed various lesions outside the brain stem. Patients who emerged from the LIS state had a significantly lower prevalence of lesions outside the brain stem than patients who remained in the LIS state did.

DISCUSSION

Investigating an unselected population-based sample of patients with vascular LIS offers important insights into the functional diversity of LIS. Although most patients remained severely disabled, even small improvements in function can substantially increase the potential for activity and participation. Additional lesions outside the brain stem seem to be common in long-lasting LIS and might be prognostic for remaining in the LIS state.

Altered brain dynamics index levels of arousal in complete locked-in syndrome

Complete locked-in syndrome (CLIS) resulting from late-stage amyotrophic lateral sclerosis (ALS) is characterised by loss of motor function and eye movements. The absence of behavioural indicators of consciousness makes the search for neuronal correlates as possible biomarkers clinically and ethically urgent. EEG-based measures of brain dynamics such as power-law exponent (PLE) and Lempel-Ziv complexity (LZC) have been shown to have explanatory power for consciousness and may provide such neuronal indices for patients with CLIS. Here, we validated PLE and LZC (calculated in a dynamic way) as benchmarks of a wide range of arousal states across different reference states of consciousness (e.g., awake, sleep stages, ketamine, sevoflurane). We show a tendency toward high PLE and low LZC, with high intra-subject fluctuations and inter-subject variability in a cohort of CLIS patients with values graded along different arousal states as in our reference data sets. In conclusion, changes in brain dynamics indicate altered arousal in CLIS. Specifically, PLE and LZC are potentially relevant biomarkers to identify or diagnose the arousal level in CLIS and to determine the optimal time point for treatment, including communication attempts.

Atypical Presentation of the Classical Form of Locked-In Syndrome in a Young Patient

Locked-in syndrome (LIS) is an uncommon neurologic disorder that manifests in quadriplegia and anarthria with preserved cognition and self-awareness. Generally, patients with LIS may live for years with preserved quality of life and cognitive function, but with severe disability. There are 3 types of LIS: classic, partial, and total. The classical form is defined by total immobility, with preservation of the ability to perform vertical eye movements, blink, and maintain a normal level of consciousness. We present an unusual case of classical LIS in a 54-year-old man who presented initially with acute-onset left lower extremity weakness and dysarthria with radiographic evidence of extensive, acute right paramedian pontine infarction and high-grade vertebral artery stenosis. However, a week later, the patient developed sudden-onset aphonia, bilateral facial palsy, and quadriplegia with repeat magnetic resonance imaging of the brain showing expansion of right paramedian pontine stroke to also involve the left paramedian pons, without significant change to the vertebral stenosis and basilar artery patency.

[Let's Watch the Movie, The Diving Bell and the Butterfly and Think About the Patient's Feelings]

The Diving Bell and the Butterfly is a movie based on the true story of an editor-in-chief, Jean-Dominique Bauby, who had locked-in syndrome due to a cerebral infarction. He made an entire story by communication with his staff using solely eye movements. The patient's real emotions to the medical staff was presented in the movie. I would highly recommend this movie, and in this article, I explain and describe locked-in syndrome and my impressions of this movie.

Investigating Structure-Function Connectivity in a Patient With Locked-In Syndrome by 7 T Magnetic Resonance Imaging: A Case Report

INTRODUCTION

Functional neuroimaging studies have been conducted to investigate cognitive and behavioral dysfunctions in locked-in syndrome (LIS). This study, we used a multimodal neuroimaging approach to investigate functional and structural connectivity in a LIS patient.

CASE REPORT

A 39-year-old patient who was in a total locked-in state was admitted in our department. The Coma Recovery Scale-Revised score, event-related potential, and ultra-high-field 7 T magnetic resonance imaging (MRI) were used to investigate this patient. White matter connectometry and seed-based resting-state functional connectivity analysis were used to compare the patient with an age-matched, sex-matched healthy control. Diffusion MRI findings indicated that fibers in the brainstem significantly decreased, especially in the cross region of pons, whereas the fibers above the brainstem in the deep brain increased particularly in the posterior cingulate cortex (PCC), the left parietal lobe, and parts of the corpus callosum. Meanwhile, using the PCC as the seed region, the functional connectivity between PCC and left parietal and occipital lobes, right occipital and temporal lobes increased, respectively, especially in the area of left inferior parietal gyrus and the postcentral gyrus, which were in accordance with the most increased fiber density areas observed in diffusion MRI.

CONCLUSIONS

These results provide tentative evidences to reveal the important role of PCC and corpus callosum in the LIS patient. These findings may be informative to the study of patients with LIS.

Methodological Recommendations for Studies on the Daily Life Implementation of Implantable Communication-Brain-Computer Interfaces for Individuals With Locked-in Syndrome

Implantable brain-computer interfaces (BCIs) promise to be a viable means to restore communication in individuals with locked-in syndrome (LIS). In 2016, we presented the world-first fully implantable BCI system that uses subdural electrocorticography electrodes to record brain signals and a subcutaneous amplifier to transmit the signals to the outside world, and that enabled an individual with LIS to communicate via a tablet computer by selecting icons in spelling software. For future clinical implementation of implantable communication-BCIs, however, much work is still needed, for example, to validate these systems in daily life settings with more participants, and to improve the speed of communication. We believe the design and execution of future studies on these and other topics may benefit from the experience we have gained. Therefore, based on relevant literature and our own experiences, we here provide an overview of procedures, as well as recommendations, for recruitment, screening, inclusion, imaging, hospital admission, implantation, training, and support of participants with LIS, for studies on daily life implementation of implantable communication-BCIs. With this article, we not only aim to inform the BCI community about important topics of concern, but also hope to contribute to improved methodological standardization of implantable BCI research.

Locked-in Syndrome Due to Meningovascular Syphilis: A Case Report and Literature Review

We herein report a 46-year-old man presenting with locked-in syndrome secondary to meningovascular syphilis. Brain magnetic resonance imaging (MRI) demonstrated multiple acute infarctions in the left ventromedial pons, right basis pontis, and left basal ganglia. His locked-in syndrome was hypothesized to have been caused by thrombosis of the small paramedian branches of the basilar artery due to syphilitic arteritis. This is a unique case of bilateral ventromedial pontine infarction caused by meningovascular syphilis that presented as locked-in syndrome. Meningovascular syphilis should be included in the differential diagnosis of uncommon stroke, particularly in young men.

[Locked-in Syndrome due to Primary Brainstem Injury:A Case Report]

Most cases of the primary brainstem injuries(PBSI)are fatal, and disturbance of consciousness is often prolonged even if lifesaving is obtained. The mechanisms of PBSI are as follows: diffuse axonal injury from acceleration/deceleration, shear strain at the midbrain, direct injury of neurovascular structures by tentorial margin, and lower brainstem injury by hyperextension of the cervical vertebrae. Though we can use both CT and MRI to diagnose, MRI is more helpful than CT in detecting, localizing, and characterizing PBSI. When the location of PBSI is limited in the ventral side of pons, it may occasionally result in locked in syndrome(LIS). Generally it is difficult to diagnose LIS with severe trauma due to the rarity of this syndrome caused by head injury. Here, we report a case of an elderly man with traumatic brainstem hemorrhage, who transiently presented LIS and finally improved.