Beyond the gaze: Communicating in chronic locked-in syndrome

Locked-in syndrome: A qualitative study of a life story

INTRODUCTION

Locked-in syndrome (LIS) is characterized by tetraplegia, anarthria, paralysis of cranial nerves, and facial musculature, with the preservation of consciousness and cognitive abilities, as well as vertical eye movements and eyelid movements, hearing, and breathing. Three types of LIS are distinguished: classic, incomplete, and total. The aim of the present study was to describe the life history of a person with LIS, as well as the wife's experience and perspective of this life history.

METHODS

A qualitative life history study was conducted with two participants: a 54-year-old man diagnosed with LIS and his 50-year-old wife. Data were collected through interviews and autobiographical documents submitted by the participants and analyzed following Braun and Clarke's method of inductive thematic analysis.

RESULTS

Five main themes were identified: (1) how to understand and overcome the new situation; (2) the process of care and rehabilitation; (3) communication; (4) writing as a way of helping oneself and others; and (5) personal autonomy and social participation.

CONCLUSION

The participants valued the support of their friends and family in the acceptance stage of the new situation, giving special importance to the communication skills and medical attention received after diagnosis.

Post-stroke aphasia rehabilitation using an adapted visual P300 brain-computer interface training: improvement over time, but specificity remains undetermined

Introduction

This study aimed to evaluate the efficacy of visual P300 brain-computer interface use to support rehabilitation of chronic language production deficits commonly experienced by individuals with a left-sided stroke resulting in post-stroke aphasia.

Methods

The study involved twelve participants, but five dropped out. Additionally, data points were missing for three participants in the remaining sample of seven participants. The participants underwent four assessments-a baseline, pre-assessment, post-assessment, and follow-up assessment. Between the pre-and post-assessment, the participants underwent at least 14 sessions of visual spelling using a brain-computer interface. The study aimed to investigate the impact of this intervention on attention, language production, and language comprehension and to determine whether there were any potential effects on quality of life and well-being.

Results

None of the participants showed a consistent improvement in attention. All participants showed an improvement in spontaneous speech production, and three participants experienced a reduction in aphasia severity. We found an improvement in subjective quality of life and daily functioning. However, we cannot rule out the possibility of unspecific effects causing or at least contributing to these results.

Conclusion

Due to challenges in assessing the patient population, resulting in a small sample size and missing data points, the results of using visual P300 brain-computer interfaces for chronic post-stroke aphasia rehabilitation are preliminary. Thus, we cannot decisively judge the potential of this approach.

Pupil dilation response elicited by violations of auditory regularities is a promising but challenging approach to probe consciousness at the bedside

Pupil dilation response (PDR) has been proposed as a physiological marker of conscious access to a stimulus or its attributes, such as novelty. In a previous study on healthy volunteers, we adapted the auditory "local global" paradigm and showed that violations of global regularity elicited a PDR. Notably without instructions, this global effect was present only in participants who could consciously report violations of global regularities. In the present study, we used a similar approach in 24 non-communicating patients affected with a Disorder of Consciousness (DoC) and compared PDR to ERPs regarding diagnostic and prognostic performance. At the group level, global effect could not be detected in DoC patients. At the individual level, the only patient with a PDR global effect was in a MCS and recovered consciousness at 6 months. Contrasting the most regular trials to the most irregular ones improved PDR's diagnostic and prognostic power in DoC patients. Pupillometry is a promising tool but requires several methodological improvements to enhance the signal-to-noise ratio and make it more robust for probing consciousness and cognition in DoC 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.

High-resolution neural recordings improve the accuracy of speech decoding

Patients suffering from debilitating neurodegenerative diseases often lose the ability to communicate, detrimentally affecting their quality of life. One solution to restore communication is to decode signals directly from the brain to enable neural speech prostheses. However, decoding has been limited by coarse neural recordings which inadequately capture the rich spatio-temporal structure of human brain signals. To resolve this limitation, we performed high-resolution, micro-electrocorticographic (µECoG) neural recordings during intra-operative speech production. We obtained neural signals with 57× higher spatial resolution and 48% higher signal-to-noise ratio compared to macro-ECoG and SEEG. This increased signal quality improved decoding by 35% compared to standard intracranial signals. Accurate decoding was dependent on the high-spatial resolution of the neural interface. Non-linear decoding models designed to utilize enhanced spatio-temporal neural information produced better results than linear techniques. We show that high-density µECoG can enable high-quality speech decoding for future neural speech prostheses.

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.

Locked-in syndrome revisited

The locked-in syndrome (LiS) is characterized by quadriplegia with preserved vertical eye and eyelid movements and retained cognitive abilities. Subcategorization, aetiologies and the anatomical foundation of LiS are discussed. The damage of different structures in the pons, mesencephalon and thalamus are attributed to symptoms of classical, complete and incomplete LiS and the locked-in plus syndrome, which is characterized by additional impairments of consciousness, making the clinical distinction to other chronic disorders of consciousness at times difficult. Other differential diagnoses are cognitive motor dissociation (CMD) and akinetic mutism. Treatment options are reviewed and an early, interdisciplinary and aggressive approach, including the provision of psychological support and coping strategies is favoured. The establishment of communication is a main goal of rehabilitation. Finally, the quality of life of LiS patients and ethical implications are considered. While patients with LiS report a high quality of life and well-being, medical professionals and caregivers have largely pessimistic perceptions. The negative view on life with LiS must be overthought and the autonomy and dignity of LiS patients prioritized. Knowledge has to be disseminated, diagnostics accelerated and technical support system development promoted. More well-designed research but also more awareness of the needs of LiS patients and their perception as individual persons is needed to enable a life with LiS that is worth living.

Assessment and management of pain/nociception in patients with disorders of consciousness or locked-in syndrome: A narrative review

The assessment and management of pain and nociception is very challenging in patients unable to communicate functionally such as patients with disorders of consciousness (DoC) or in locked-in syndrome (LIS). In a clinical setting, the detection of signs of pain and nociception by the medical staff is therefore essential for the wellbeing and management of these patients. However, there is still a lot unknown and a lack of clear guidelines regarding the assessment, management and treatment of pain and nociception in these populations. The purpose of this narrative review is to examine the current knowledge regarding this issue by covering different topics such as: the neurophysiology of pain and nociception (in healthy subjects and patients), the source and impact of nociception and pain in DoC and LIS and, finally, the assessment and treatment of pain and nociception in these populations. In this review we will also give possible research directions that could help to improve the management of this specific population of severely brain damaged patients.

Brain Computer Interfaces and Communication Disabilities: Ethical, Legal, and Social Aspects of Decoding Speech From the Brain

A brain-computer interface technology that can decode the neural signals associated with attempted but unarticulated speech could offer a future efficient means of communication for people with severe motor impairments. Recent demonstrations have validated this approach. Here we assume that it will be possible in future to decode imagined (i.e., attempted but unarticulated) speech in people with severe motor impairments, and we consider the characteristics that could maximize the social utility of a BCI for communication. As a social interaction, communication involves the needs and goals of both speaker and listener, particularly in contexts that have significant potential consequences. We explore three high-consequence legal situations in which neurally-decoded speech could have implications: Testimony, where decoded speech is used as evidence; Consent and Capacity, where it may be used as a means of agency and participation such as consent to medical treatment; and Harm, where such communications may be networked or may cause harm to others. We then illustrate how design choices might impact the social and legal acceptability of these technologies.

French Survey on Pain Perception and Management in Patients with Locked-In Syndrome

Patients with locked-in syndrome (LIS) may suffer from pain, which can significantly affect their daily life and well-being. In this study, we aim to investigate the presence and the management of pain in LIS patients. Fifty-one participants completed a survey collecting socio-demographic information and detailed reports regarding pain perception and management (type and frequency of pain, daily impact of pain, treatments). Almost half of the LIS patients reported experiencing pain (49%) that affected their quality of life, sleep and cognition. The majority of these patients reported that they did not communicate their pain to clinical staff. Out of the 25 patients reporting pain, 18 (72%) received treatment (60% pharmacological, 12% non-pharmacological) and described the treatment efficacy as 'moderate'. In addition, 14 (56%) patients were willing to try other non-pharmacological treatments, such as hypnosis or meditation. This study provides a comprehensive characterization of pain perception in LIS patients and highlights the lack of guidelines for pain detection and its management. This is especially pertinent given that pain affects diagnoses, by either inducing fatigue or by using pharmacological treatments that modulate the levels of wakefulness and concentration of such patients.

Locked-In Syndrome: A Systematic Review of Long-Term Management and Prognosis

Locked-in syndrome (LIS) is a neurological disorder in which there is damage to the ventral pons and caudal midbrain. An ischemic cause, such as basilar artery occlusion, can often lead to LIS. LIS has three subtypes: classical, partial, and total. There is loss of motion in the four extremities in classical LIS, loss of horizontal gaze, and aphasia. In partial LIS, the patient still has some motor function. Complete LIS has the worst outcome because patients cannot blink or have vertical gaze, thus rendering them incapable of communicating. Most cases of LIS occur due to ischemic infarcts. These patients require a great deal of physical rehabilitation to regain partial motor ability and a means to communicate. While the clinical features and pathophysiology are known, the prognosis and long-term treatment remain unknown. We conducted a systematic review using the Meta-Analysis Of Observational Studies in Epidemiology (MOOSE) protocol. We use an advanced PubMed strategy using the inclusion criteria of observational studies or clinical trials conducted in the last 20 years, written in English, and conducted on humans. We excluded systematic reviews, literature reviews, metanalysis, and studies that did not meet the outcomes of our objectives. The prognosis of LIS is not good, and most patients remain locked in, with poor quality of life, especially motor functions. Respiratory failure and depression are big comorbidities. In the acute setting, patients benefit from rapid intervention. The subacute treatment needs to manage aggressively to improve functional scores best. The long-term treatment focus is on the quality of life and managing comorbidities.

Literature review on assistive devices available for quadriplegic people: Indian context

PURPOSE

This literature review aims to find the current state of the art in self-help devices (SHD) available for people with quadriplegia.

MATERIALS AND METHODS

We searched original articles, technical and case studies, conference articles, and literature reviews published between 2014 to 2019 with the keywords ("Self-help devices" OR "Assistive Devices" OR "Assistive Product" OR "Assistive Technology") AND "Quadriplegia" in Science Direct, Pubmed, IEEE Xplore digital library and Web of Science.

RESULTS

Total 222 articles were found. After removing duplicates and screening these articles based on their title and abstracts 80 articles remained. After this, we reviewed the full text, and articles unrelated to SHD development or about the patients who require mechanical ventilation or where the upper limb is functional (C2 or above and T2 or below injuries) were discarded. After the exclusion of articles using the above-mentioned criterion 75 articles were used for further review.

CONCLUSION

The abandonment rate of SHD currently available in the literature is very high. The major requirement of the people was independence and improved quality of life. The situation in India is very bad as compared to the developed countries. The people with spinal cord injury in India are uneducated and very poor, with an average income of 3000 ₹ (41$). They require SHDs and training specially designed for them, keeping their needs in mind.Implications for rehabilitationPeople with quadriplegia are totally dependent on caregivers. Assistive devices not only help these people to do day-to-day tasks but also provides them self-confidence.Even though there are a lot of self-help devices currently available, still they are not able to fulfil the requirements of people with quadriplegia, hence there is a very high abandonment rate of such devices.This study provides an evidence that developing devices after understanding the functional and non-functional requirements of these subjects will decrease the abandonment rate and increase the effectiveness of the device.The results of this study can be used for planning and developing assistive devices which are more focussed on fulfilling the requirements of people with quadriplegia.

Effects of simulated visual acuity and ocular motility impairments on SSVEP brain-computer interface performance: An experiment with Shuffle Speller

Individuals with severe speech and physical impairments may have concomitant visual acuity impairments (VAI) or ocular motility impairments (OMI) impacting visual BCI use. We report on the use of the Shuffle Speller typing interface for an SSVEP BCI copy-spelling task under three conditions: simulated VAI, simulated OMI, and unimpaired vision. To mitigate the effect of visual impairments, we introduce a method that adaptively selects a user-specific trial length to maximize expected information transfer rate (ITR); expected ITR is shown to closely approximate the rate of correct letter selections. All participants could type under the unimpaired and simulated VAI conditions, with no significant differences in typing accuracy or speed. Most participants (31 of 37) could not type under the simulated OMI condition; some achieved high accuracy but with slower typing speeds. Reported workload and discomfort were low, and satisfaction high, under the unimpaired and simulated VAI conditions. Implications and future directions to examine effect of visual impairment on BCI use is discussed.

Performance Differences Using a Vibro-Tactile P300 BCI in LIS-Patients Diagnosed With Stroke and ALS

Patients with locked-in syndrome (LIS) are typically unable to move or communicate and can be misdiagnosed as patients with disorders of consciousness (DOC). Behavioral assessment scales are limited in their ability to detect signs of consciousness in this population. Recent research has shown that brain-computer interface (BCI) technology could supplement behavioral scales and allows to establish communication with these severely disabled patients. In this study, we compared the vibro-tactile P300 based BCI performance in two groups of patients with LIS of different etiologies: stroke (n = 6) and amyotrophic lateral sclerosis (ALS) (n = 9). Two vibro-tactile paradigms were administered to the patients to assess conscious function and command following. The first paradigm is called vibrotactile evoked potentials (EPs) with two tactors (VT2), where two stimulators were placed on the patient’s left and right wrist, respectively. The patients were asked to count the rare stimuli presented to one wrist to elicit a P300 complex to target stimuli only. In the second paradigm, namely vibrotactile EPs with three tactors (VT3), two stimulators were placed on the wrists as done in VT2, and one additional stimulator was placed on his/her back. The task was to count the rare stimuli presented to one wrist, to elicit the event-related potentials (ERPs). The VT3 paradigm could also be used for communication. For this purpose, the patient had to count the stimuli presented to the left hand to answer “yes” and to count the stimuli presented to the right hand to answer “no.” All patients except one performed above chance level in at least one run in the VT2 paradigm. In the VT3 paradigm, all 6 stroke patients and 8/9 ALS patients showed at least one run above chance. Overall, patients achieved higher accuracies in VT2 than VT3. LIS patients due to ALS exhibited higher accuracies that LIS patients due to stroke, in both the VT2 and VT3 paradigms. These initial data suggest that controlling this type of BCI requires specific cognitive abilities that may be impaired in certain sub-groups of severely motor-impaired patients. Future studies on a larger cohort of patients are needed to better identify and understand the underlying cortical mechanisms of these differences.

Assessment of needs, psychological impact and quality of life in families of patients with locked-in syndrome

OBJECTIVE

Family needs of patients with acquired brain injuries have been studied for about three decades. In this study, we assessed the needs, the quality of life and the psychological state of relatives of patients with locked-in syndrome (LIS).

DESIGN

A survey was carried out using the family needs' questionnaire (FNQ).

SUBJECTS AND METHODS

Thirty relatives of patients with LIS fully completed the FNQ.

RESULTS

The most important need reported by families corresponded to the need for medical information. The highest percentage of satisfaction (66%) was also observed for this need. Among the needs for information, specifically, the most important for LIS' relatives was to know that the patient's needs and wishes were respected by the professional staff, which were fulfilled in 93% of the sample. The need for emotional support was the least important and had the lowest percentage of satisfaction (55%). The number of met/unmet needs correlated with the quality of life of the families. Most of the relatives reported anxiety feelings and depressive thoughts.

CONCLUSIONS

Receiving accurate medical information is the most important need for family of patients with LIS and their quality of life is correlated with the fulfilment of their needs.

Cognitive Processing in Non-Communicative Patients: What Can Event-Related Potentials Tell Us?

Event-related potentials (ERP) have been proposed to improve the differential diagnosis of non-responsive patients. We investigated the potential of the P300 as a reliable marker of conscious processing in patients with locked-in syndrome (LIS). Eleven chronic LIS patients and 10 healthy subjects (HS) listened to a complex-tone auditory oddball paradigm, first in a passive condition (listen to the sounds) and then in an active condition (counting the deviant tones). Seven out of nine HS displayed a P300 waveform in the passive condition and all in the active condition. HS showed statistically significant changes in peak and area amplitude between conditions. Three out of seven LIS patients showed the P3 waveform in the passive condition and five of seven in the active condition. No changes in peak amplitude and only a significant difference at one electrode in area amplitude were observed in this group between conditions. We conclude that, in spite of keeping full consciousness and intact or nearly intact cortical functions, compared to HS, LIS patients present less reliable results when testing with ERP, specifically in the passive condition. We thus strongly recommend applying ERP paradigms in an active condition when evaluating consciousness in non-responsive patients.