The Cognitive Assessment by Visual Election (CAVE): A pilot study to develop a cognitive assessment tool for people emerging from disorders of consciousness

Assessing consciousness and cognition in disorders of consciousness

Detecting willful cognition in these patients is known to be challenging due to the patients' motor disabilities and high vigilance fluctuations but also due to the lack of expertise and use of adequate tools to assess these patients in specific settings. This review will discuss the main disorders of consciousness after severe brain injury, how to assess consciousness and cognition in these patients, as well as the challenges and tools available to overcome these challenges and reach an accurate diagnosis.

Is frontoparietal electroencephalogram activity related to the level of functional disability in patients emerging from a minimally conscious state? A preliminary study

Objective

When regaining consciousness, patients who emerge from a minimally conscious state (EMCS) present with different levels of functional disability, which pose great challenges for treatment. This study investigated the frontoparietal activity in EMCS patients and its effects on functional disability.

Materials and methods

In this preliminary study, 12 EMCS patients and 12 healthy controls were recruited. We recorded a resting-state scalp electroencephalogram (EEG) for at least 5 min for each participant. Each patient was assessed using the disability rating scale (DRS) to determine the level of functional disability. We analyzed the EEG power spectral density and sensor-level functional connectivity in relation to the patient’s functional disability.

Results

In the frontoparietal region, EMCS patients demonstrated lower relative beta power (P < 0.01) and higher weighted phase lag index (wPLI) values in the theta (P < 0.01) and gamma (P < 0.01) bands than healthy controls. The frontoparietal theta wPLI values of EMCS patients were positively correlated with the DRS scores (r_s = 0.629, P = 0.029). At the whole-brain level, EMCS patients only had higher wPLI values in the theta band (P < 0.01) than healthy controls. The whole-brain theta wPLI values of EMCS patients were also positively correlated with the DRS scores (r_s = 0.650, P = 0.022). No significant difference in the power and connectivity between the frontoparietal region and the whole brain in EMCS patients was observed.

Conclusion

EMCS patients still experience neural dysfunction, especially in the frontoparietal region. However, the theta connectivity in the frontoparietal region did not increase specifically. At the level of the whole brain, the same shift could also be seen. Theta functional connectivity in the whole brain may underlie different levels of functional disability.

Development of an Italian version of the functional communication measures and preliminary observations in patients with severe acquired brain injury and emerging from a prolonged disorder of consciousness

A proper assessment tool targeting communicative abilities in patients with severe acquired brain injury (sABI), and particularly for patients recovering from prolonged disorders of consciousness (pDoC), is lacking. The Functional Communication Measures (FCM) consists of a series of rating scales, ranging from 1 (least functional) to 7 (most functional), assessing cognitive requirements for communication and communicative abilities in patients with brain injury. Here we presented exploratory data concerning an Italian adaptation of FCM administered to patients with sABI. After the translation into Italian language, the FCM was blindly administered by 2 independent speech therapists to 19 patients (10 males; median age = 58; IQR = 25) admitted to neurorehabilitation unit after sABI with a level of cognitive functioning between 4 and 8. Two further patients who presented a pDoC after sABI and emerged from the minimally conscious state (a 64-year-old female and a 74-year-old female) were also evaluated by means of the FCM, the Coma Recovery Scale-Revised, and the Disability Rating Scale. Inter-rater agreement was almost perfect for attention, memory, and swallowing items, and substantial for communicative-augmentative communication, motor speech, spoken language expression, and spoken language comprehension. Importantly, in the two pDoC patients, the FCM identified two different functioning profiles in the attention, swallowing, motor speech, and spoken language expression scales, notwithstanding the two patients achieved the same scores on scales for functional disability and consciousness level. The FCM might be a promising and easy-to-administer tool to assess communicative functions in patients with sABI, independently from evaluation of functional disability.

Language Assessment in Patients with Disorders of Consciousness

The assessment of residual language abilities in patients with disorders of consciousness (DoC) after severe brain injury is particularly challenging due to their limited behavioral repertoire. Moreover, associated language impairment such as receptive aphasia may lead to an underestimation of actual consciousness levels. In this review, we examine past research on the assessment of residual language processing in DoC patients, and we discuss currently available tools for identifying language-specific abilities and their prognostic value. We first highlight the need for validated and sensitive bedside behavioral assessment tools for residual language abilities in DoC patients. As regards neuroimaging and electrophysiological methods, the tasks involving higher level linguistic commands appear to be the most informative about level of consciousness and have the best prognostic value. Neuroimaging methods should be combined with the most appropriate behavioral tools in multimodal assessment protocols to assess receptive language abilities in DoC patients in the most complete and sensitive manner.

Update on diagnosis in disorders of consciousness

INTRODUCTION

New guidelines regarding the diagnosis of disorders of consciousness (DOC) (such as vegetative state and minimally conscious state) have recently been published by the American Academy of Neurology and the European Academy of Neurology. This follows an impressive number of prospective studies performed on DOC and recent multi-centric studies with larger sample size, which have gathered precious information on the recovery of cohort of patients through years and which now call for a better management of patients with DOC.

AREAS COVERED

This review will discuss recent updates on the clinical entities of DOC, the challenges for an accurate diagnosis and the last developments in diagnostic tools.

EXPERT OPINION

The authors will also discuss the impact of the new guidelines on their way of diagnosing patients and how diagnosis will most likely change in a near future.

Post-comatose patients with minimal consciousness tend to preserve reading comprehension skills but neglect syntax and spelling

Modern eye tracking technology provides a means for communication with patients suffering from disorders of consciousness (DoC) or remaining in locked-in-state. However, being able to use an eye tracker for controlling text-based contents by such patients requires preserved reading ability in the first place. To our knowledge, this aspect, although of great social importance, so far has seemed to be neglected. In the paper, we presented the possibility of using an eye-tracking technology for assessing reading comprehension skills in post-comatose patients with minimal consciousness. We prepared various syllable-, word- and sentence-based tasks, controlled by gaze, used for assessing the reading comprehension skills. The obtained results showed that people with minimal consciousness preserved the reading comprehension skills, in most cases to a high extent, but had difficulties with recognizing errors in the written text. The ability to maintain attention during performing the tasks was in statistically significant correlation with motivation, and that one was in a statistically significant correlation with the reading ability. The results indicate that post-comatose patients with minimal consciousness can read words and sentences, hence some useful hints may be provided for the development of gaze tracking-based human-computer interfaces for these people.

Diagnosis of May-Thurner Syndrome in a Case of Acute Pulmonary Embolism with Multiple Risk Factors: A Case Report and Review of Literature

Background: May-Thurner Syndrome (MTS) is aniliac vein compression syndrome which results in a thrombosis of the common left iliac vein. The main cause of this compression is the overlying right common iliac artery. Method: In this article we describe the case of a 35-year-old woman with bilateral lobar pulmonary embolism (PE) together with an investigation of the risk factors leading to PE. The final diagnosis was a MTS with asymptomatic left internal vein thrombosis, further complicated by a PE. Results: Precipitating factors were polycystic ovarian syndrome, combined oral contraceptives and a possible protein S deficiency.Treatment encompassed anticoagulation during the first year of treatment. Re-evaluation together with further retesting of protein S and imaging will determine the need for an endovascular approach to the iliac vein compression. In this article we discuss the diagnostic approach to patients with PE with an asymptomatic deep venous thrombosis. Conclusions: This article seeks to draw attention to MTS as an incompletely studied syndrome which is potentially frequent in female patients with PE and interacts with other factors to increase the risk of a thrombosis. MTS should be considered in the differential diagnosis of a patient with PE in addition to patients presenting with a proximal deep venous thrombosis.

Technology-aided leisure and communication support in extensive neuro-motor and communication impairments

BACKGROUND

Individuals with extensive neuro-motor impairment and lack of speech are known to remain fairly isolated and rely on others. Yet, there is only limited evidence as to how one can help them to reach a level of independence in relevant areas such as leisure and communication. This study assessed a program based on everyday technology to support leisure and communication engagement in six of those individuals.

CASE REPORT

The six cases (adults) were non-ambulatory and had no speech or functional active communication. Their neurological damage was due to extensive left hemispheric hemorrhagic or ischemic lesion and to critical illness polyneuropathy aggravating a condition of neonatal encephalopathy. A smartphone-based program was developed and successfully used to enable them to access leisure activities (e.g., listening to music) and communication (e.g., sending text messages or calling the caregiver).

CLINICAL REHABILITATION IMPACT

Cases like those presented in this study may reach independent and functional engagement if supported via specific, technology-aided intervention programs.

Brain, Behavior, and Cognitive Interplay in Disorders of Consciousness: A Multiple Case Study

Patients with prolonged disorders of consciousness (DoC) after severe brain injury may present residual behavioral and cognitive functions. Yet the bedside assessment of these functions is compromised by patients' multiple impairments. Standardized behavioral scales such as the Coma Recovery Scale-Revised (CRS-R) have been developed to diagnose DoC, but there is also a need for neuropsychological measurement in these patients. The Cognitive Assessment by Visual Election (CAVE) was therefore recently created. In this study, we describe five patients in minimally conscious state (MCS) or emerging from the MCS (EMCS). Their cognitive profiles, derived from the CRS-R and CAVE, are presented alongside their neuroimaging results using structural magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET). Scores on the CAVE decreased along with the CRS-R total score, establishing a consistent behavioral/cognitive profile for each patient. Out of these five cases, the one with highest CRS-R and CAVE performance had the least extended cerebral hypometabolism. All patients showed structural and functional brain impairments that were consistent with their behavioral/cognitive profile as based on previous literature. For instance, the presence of visual and motor residual functions was respectively associated with a relative preservation of occipital and motor cortex/cerebellum metabolism. Moreover, residual language comprehension skills were found in the presence of preserved temporal and angular cortex metabolism. Some patients also presented structural impairment of hippocampus, suggesting the presence of memory impairments. Our results suggest that brain-behavior relationships might be observed even in severely brain-injured patients and they highlight the importance of developing new tools to assess residual cognition and language in MCS and EMCS patients. Indeed, a better characterization of their cognitive profile will be helpful in preparation of rehabilitation programs and daily routines.