A measure of neurobehavioral functioning after coma. Part II: Clinical and scientific implementation

An assistive technology program for enabling five adolescents emerging from a minimally conscious state to engage in communication, occupation, and leisure opportunities

BACKGROUND

Post-coma patients emerging from a minimally conscious state may have extensive motor disabilities and pose serious challenges to medical centers and home settings.

OBJECTIVES

To promote academic performance and communication skills of post-coma individuals with traumatic brain injuries emerging from a minimally conscious state through an Assistive Technology setup. To evaluate its effects on the participants' positive participation. To generalize the learning process. To assess the intervention's clinical and social validity.

METHOD

Study I included five adolescents exposed to an Assistive Technology setup enabling them with targeted adaptive behaviors. Study II involved fifty external raters in a social validation assessment.

RESULTS

Data evidenced an improved performance of all the participants during the intervention, assessed through a concurrent multiple baseline design across participants. Social raters favorably scored the use of the technology.

CONCLUSION

An Assistive Technology setup may be helpful to enhance the performance and positive participation of adolescents with traumatic brain injuries emerging from a minimally conscious state.

Epilepsy in prolonged disorders of consciousness: a systematic review

To date, no guideline exists for the management of epilepsy in patients with prolonged Disorders of Consciousness (DoC). This review aimed to assess the occurrence of epilepsy and epileptic abnormalities (EA) in these patients, to determine their impact on recovery; and to review the effect of antiepileptic drugs (AED) and therapeutic interventions on seizure occurrence and consciousness recovery. A structured search for studies on prolonged DoC and epilepsy was undertaken following PRISMA guidelines. From an initial search resulting in 5,775 titles, twelve studies met inclusion criteria. The occurrence of epilepsy and EA in DoC was poorly and inconsistently reported across studies. The results estimated a seizure prevalence of 27% in DoC. No conclusive data were found for the effects of AED on recovery nor on the influence of any therapeutic interventions on seizure occurrence. Given the scarcity of data, it is premature to make evidence-based recommendations on epilepsy in prolonged DoC. Based on this review and current clinical practices the following are recommended: (1) repeated standard EEG for detecting seizures and EA; (2) treating epilepsy while avoiding AEDs with sedating or cognitive side-effects. Future research should use standardized classification systems for seizures and EA.

Responsiveness, Minimal Detectable Change, and Minimally Clinically Important Differences for the Disorders of Consciousness Scale

OBJECTIVES

To determine the responsiveness, minimal detectable change (MDC95), and minimally clinically important difference (MCID) of the Disorders of Consciousness Scale (DOCS-25) in patients with severe traumatic brain injury (TBI) and to report the percentages of patients' change scores exceeding MDC and MCID after 3 weeks of inpatient rehabilitation.

SETTING

Post-acute rehabilitation hospitals.

PARTICIPANTS

One hundred seventy-two patients with severe TBI. Ninety-two were included in the DOCS-25 3-week analysis.

DESIGN

Retrospective cohort study.

MAIN MEASURE(S)

Disorders of Consciousness Scale, Glasgow Coma Scale.

RESULTS

The effect size and standardized response mean of the DOCS-25 for those who improved were 0.45 and 1.3, respectively-moderate to large by Cohen criteria. The MDC95 (95% confidence interval) was 5.6. Distribution-based MCIDs for small (0.20 SD), moderate (0.33 SD), and large (0.50 SD) differences were 2.6 units, 4.4 units, and 6.6 units, respectively. The anchor-based MCID was 8.6 units. On average, patients who improved (n = 57) gained 14.5 units by week 3, exceeding the anchor-based MCID. On average, patients who did not improve (n = 35) declined by 7.2 units, which exceeds both the MDC95 and the largest distribution-based MCID.

CONCLUSION(S)

The DOCS-25 is a responsive, clinician-observed assessment tool for capturing change in neurobehavioral function in adults recovering from severe TBI. This is the first study to provide evidence for the size of neurobehavioral function change that might indicate meaningful recovery in patients with severe TBI. Results from this study may support future research by better informing sample size calculations for clinical trials and also assist clinicians in identifying when variation in level of consciousness is consequential enough to warrant changes in intervention.

The role of the SMART and WHIM in behavioural assessment of disorders of consciousness: clinical utility and scope for a symbiotic relationship

As the prevalence and incidence of disorders of consciousness (DoC) increase, researchers and clinicians are tasked with developing best practice assessment techniques. Neurobehavioural assessment remains the most clinically available method of measuring consciousness. Neuroimaging and other physiological measurements are demonstrating promise in supporting this assessment but many of these techniques require further research and are not widely available in sub-acute and long-term care settings. No study to date has explored in-depth complementary use of multiple neurobehavioural assessments in aiding beside assessment of consciousness. This paper describes and proposes complementary use of two commonly used standardised neurobehavioural assessments. The Sensory Modality Assessment and Rehabilitation Technique (SMART) and the Wessex Head Injury Matrix (WHIM) both have specific aims and play an important role in behavioural assessment across the care continuum. This paper proposes that when used together appropriately these two assessments promote best practice and strengthen behavioural assessment of consciousness by providing increased opportunities to capture awareness. Further research into use of more than one neurobehavioural tool is highlighted as an important area of inquiry for this heterogeneous population not only in clinical practice but also in research.

Effects of preference and sensory modality on behavioural reaction in patients with disorders of consciousness

BACKGROUND

Reliable evaluation of patients with unresponsive wakefulness syndrome (UWS) or in a minimally conscious state (MCS) remains a major challenge. It has been suggested that the expression of residual cerebral function could be improved by allowing patients to listen to their favourite music. However, the potential effect of music on behavioural responsiveness, as well as the effect of preferred stimuli in other sensory modalities (e.g. olfaction), remain poorly understood.

OBJECTIVE

The aim of our study was to investigate the effect of sensory modality (auditory versus olfactory) and preference (preferred versus neutral) of the test stimuli on patients' subsequent performance on the Coma Recovery Scale-Revised (CRS-R).

RESEARCH DESIGN

Within-subject design because of inter-individual differences between patients.

METHODS AND PROCEDURES

We studied four items from the CRS-R (visual pursuit using a mirror, auditory localization of the own name and two movements to command) in 13 patients (7 MCS; 6 UWS).

MAIN OUTCOMES AND RESULTS

Auditory stimuli triggered higher responsiveness compared to olfactory stimuli, and preferred stimuli were followed by higher scores than did neutral stimuli.

CONCLUSIONS

Findings suggest that preferred auditory stimuli at the bedside contribute to the expression of residual function and could improve the diagnostic assessment.

The Early Functional Abilities (EFA) scale to assess neurological and neurosurgical early rehabilitation patients

Background

It is difficult to assess neurological and neurosurgical early rehabilitation patients comprehensively. Available scales focus on activities of daily living (Barthel (BI) and Early Rehabilitation Barthel Index (ERBI)) or wakefulness (Glasgow Coma Scale (GCS), Coma Remission Scale (CRS)) while cognitive items are missing.

Methods

The Early Functional Abilities (EFA) scale comprises 20 items referring to activities of daily living (ADL), wakefulness and cognitive abilities. To evaluate its validity, n = 623 early neurological and neurosurgical rehabilitation patients (most of them after ischemic stroke or cerebral bleeding) were assessed on admission using the EFA, ERBI, GCS, CRS and measures of morbidity (co-diagnoses).

Results

The more co-diagnoses the lower EFA sum scores were obtained (Spearman-Rho r_s = -0.509, p < 0.001). EFA predicted length of stay (LOS, r_s = -0.565, p < 0.001) and BI at discharge (r_s = 0.571, p < 0.001).

Conclusions

The results suggest that EFA is a valid instrument to assess critically ill neurological and neurosurgical early rehabilitation patients. It may be used as a measure of morbidity and a predictor of LOS and outcome. Further studies are strongly encouraged.

Prescribing multiple neurostimulants during rehabilitation for severe brain injury

BACKGROUND

Despite a lack of clear evidence, multiple neurostimulants are commonly provided after severe brain injury (BI). The purpose of this study is to determine if the number of neurostimulants received during rehabilitation was associated with recovery of full consciousness or improved neurobehavioral function after severe BI.

METHOD

Data from 115 participants were extracted from a neurobehavioral observational study database for this exploratory, retrospective analysis. Univariate optimal data analysis was conducted to determine if the number of neurostimulants influenced classification of four outcomes: recovery of full consciousness during rehabilitation, recovery of full consciousness within one year of injury, and meaningful neurobehavioral improvement during rehabilitation defined as either at least a 4.7 unit (minimal detectable change) or 2.58 unit (minimal clinically important difference) gain on the Disorders of Consciousness Scale-25 (DOCS-25).

RESULTS

Number of neurostimulants was not significantly (P > 0.05) associated with recovery of full consciousness during rehabilitation, within one year of injury, or meaningful neurobehavioral improvement using the DOCS-25.

CONCLUSIONS

Receiving multiple neurostimulants during rehabilitation may not influence recovery of full consciousness or meaningful neurobehavioral improvement. Given costs associated with additional medication, future research is needed to guide physicians about the merits of prescribing multiple neurostimulants during rehabilitation after severe BI.

Responsiveness of Instruments to Assess Disorders of Consciousness: A Literature Review

Objectives: To summarise available evidence for responsiveness of six key assessments used with patients with disorders of consciousness: Coma Recovery Scale – Revised (CRS-R), Disorders Of Consciousness Scale (DOCS), Sensory Modality Assessment and Rehabilitation Technique (SMART), Sensory Stimulation Assessment Measure (SSAM), Wessex Head Injury Matrix (WHIM), and the Western Neuro Sensory Stimulation Profile (WNSSP).

Method: A literature search of five electronic databases was conducted using a systematic search strategy. Relevant literature was evaluated and pertinent information extracted.

Results: Database searches using key terms initially yielded 132 articles. Following review for inclusion identified 24 articles. No studies were specifically designed to investigate responsiveness of any of the measures and therefore responsiveness data were either based on statistical significance of change post-treatment or descriptive analysis of change scores. The majority of studies identified used the CRS-R (n= 11), WHIM (n= 5) and WNSSP (n= 6) and have established responsiveness to change. There is some preliminary evidence for the responsiveness of the other measures, based on very few available studies: DOCS (n= 2), SMART (n= 1) or SSAM (n= 1).

Conclusion: Future studies should seek to include responsiveness analysis, particularly in relation to the DOCS, SMART and SSAM.

From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness

Functional neuroimaging and electrophysiology studies are changing our understanding of patients with coma and related states. Some severely brain damaged patients may show residual cortical processing in the absence of behavioural signs of consciousness. Given these new findings, the diagnostic errors and their potential effects on treatment as well as concerns regarding the negative associations intrinsic to the term vegetative state, the European Task Force on Disorders of Consciousness has recently proposed the more neutral and descriptive term unresponsive wakefulness syndrome. When vegetative/unresponsive patients show minimal signs of consciousness but are unable to reliably communicate the term minimally responsive or minimally conscious state (MCS) is used. MCS was recently subcategorized based on the complexity of patients' behaviours: MCS+ describes high-level behavioural responses (i.e., command following, intelligible verbalizations or non-functional communication) and MCS- describes low-level behavioural responses (i.e., visual pursuit, localization of noxious stimulation or contingent behaviour such as appropriate smiling or crying to emotional stimuli). Finally, patients who show non-behavioural evidence of consciousness or communication only measurable via para-clinical testing (i.e., functional MRI, positron emission tomography, EEG or evoked potentials) can be considered to be in a functional locked-in syndrome. An improved assessment of brain function in coma and related states is not only changing nosology and medical care but also offers a better-documented diagnosis and prognosis and helps to further identify the neural correlates of human consciousness.

Chronic consciousness disorders

Although philosophers and cognitive neuroscientists have struggled to define human consciousness, physicians can identify and assess its two clinical dimensions: wakefulness and awareness. A comatose patient has neither wakefulness nor awareness; a patient in a vegetative state has wakefulness without awareness; and a minimally conscious patient has both, but awareness is impaired. Syndromes of unconsciousness have established diagnostic criteria, but they encompass a spectrum of severity of brain damage and have indistinct boundaries. Functional neuroimaging using PET and fMRI have provided a new and complementary way to assess consciousness. Several recent provocative studies suggest that fMRI in unresponsive patients may detect evidence of conscious awareness when a careful neurological examination cannot. If these findings are verified by future studies, functional neuroimaging technologies will alter clinical practices concerning the diagnosis, classification, and prognosis of unconscious patients, and will lead to a greater understanding of the biology of human consciousness.

Establishing a prognosis for functional outcome during coma recovery

PRIMARY OBJECTIVE

One of the most challenging tasks for clinicians caring for survivors of severe brain injury (BI) is establishing a prognosis, for long-term functional outcome, while the patient is unconscious. The objective of this article is to report findings regarding the prediction of functional outcomes 1-year after severe BI using data available when the patient is unconscious.

RESEARCH DESIGN

Longitudinal prognostication study.

METHODS AND PROCEDURES

Persons unconscious after severe BI who present to inpatient (IP) rehabilitation hospitals in the Midwestern US are enrolled in an ongoing study. Each subject is followed for 1-year and the final outcome interview includes approximately 70 questions; 32 of these questions are from the Craig Handicap Assessment and Reporting Technique (CHART). A sample of 63 persons was abstracted from the study database to examine the predictability of 42 independent variables and 16 dichotomous outcomes.

MAIN OUTCOMES AND RESULTS

Twelve of the 16 dichotomous outcomes were found to be significantly predictable (p < 0.05). These involve activity, participation, environment and quality of life outcomes. Ten predictors were found to be significant (p < 0.05): aetiology (Closed Head Injury vs. Other BI), presence of urinary tract infection (UTI), seizure, hypertension during IP rehabilitation, veteran benefit eligibility, health insurance, marital status at injury, whether or not recovery of consciousness occurred within 1 year, the number of days between injury and admission to acute rehabilitation and the average length of IP rehabilitation stay. Eight of the 10 variables are available early after injury or when the patient is unconscious.

A learning setup for a post-coma adolescent with profound multiple disabilities involving small forehead movements and new microswitch technology

PURPOSE

A learning setup was arranged for an adolescent with profound multiple disabilities and a diagnosis of vegetative state. Signs of learning by the adolescent would underline an improvement in his immediate situation with potential implications for his general prospect, and could help revise his diagnosis.

METHOD

The response adopted in the learning setup was forehead skin movement. The microswitch technology used for detecting such a response consisted of (a) an optic sensor (i.e., barcode reader), (b) a small tag with horizontal bars attached to the participant's forehead, and (c) an electronic control system that activated stimuli in relation to the participant's forehead responses. The study followed an ABABACAB sequence, in which A represented baseline periods, B intervention periods with stimuli contingent on the response, and C a control condition with stimuli presented non-contingently.

RESULTS

Data showed that the level of responding during the B phases was significantly higher than the levels observed during the A phases as well as the C phase, indicating clear signs of learning.

CONCLUSIONS

Intervention strategies based on a learning format and suitable technology might be useful to improve the situation and prospect of persons with profound multiple disabilities and a diagnosis of vegetative state.

Repetitive transcranial magnetic stimulation-associated neurobehavioral gains during coma recovery

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive method to induce changes in cortical neural excitability. This report presents findings from the first participant of a safety and efficacy study that examined a therapeutic rTMS protocol for persons with severe traumatic brain injury (TBI).

OBJECTIVE

The primary hypothesis was that there will be no adverse events related to the provision of a 6-week rTMS protocol for persons with severe TBI who remain, at best, in a minimally conscious state for longer than 3 months. The secondary hypothesis was that the rTMS protocol would induce significant neurobehavioral gains during treatment and that these gains would persist at 6-week follow-up.

METHODS

A 6-week rTMS protocol (30 sessions) was delivered to a 26-year-old man who remained in a vegetative state 287 days after severe TBI. Stimulation was directed over the right dorsolateral prefrontal cortex. Repeated safety measures, neurobehavioral assessments, clinical examinations, and evoked potentials (EP) were obtained at baseline, every fifth rTMS session (weekly), and at a 6-week follow-up.

RESULTS

There were no adverse events related to the provision of rTMS treatment. A trend toward significant (P = .066) neurobehavioral gains was temporally related to provision of rTMS. Left-sided brain stem auditory EP wave V latencies and waves I to V interpeak latencies improved along with neurobehavioral gains during provision of rTMS, suggesting that improved neural conduction in the pathway mediated the neurobehavioral improvements.

CONCLUSIONS

Repetitive TMS merits further investigation as a safe therapeutic intervention to alter neural activity, to modulate neural activity, and/or to facilitate recovery in persons with disordered consciousness subsequent to severe TBI.

Chronic disorders of consciousness

The vegetative state and the minimally conscious state are disorders of consciousness that can be acute and reversible or chronic and irreversible. Diffuse lesions of the thalami, cortical neurons, or the white-matter tracts that connect them cause the vegetative state, which is wakefulness without awareness. Functional imaging with PET and functional MRI shows activation of primary cortical areas with stimulation, but not of secondary areas or distributed neural networks that would indicate awareness. Vegetative state has a poor prognosis for recovery of awareness when present for more than a year in traumatic cases and for 3 months in non-traumatic cases. Patients in minimally conscious state are poorly responsive to stimuli, but show intermittent awareness behaviours. Indeed, findings of preliminary functional imaging studies suggest that some patients could have substantially intact awareness. The outcomes of minimally conscious state are variable. Stimulation treatments have been disappointing in vegetative state but occasionally improve minimally conscious state. Treatment decisions for patients in vegetative state or minimally conscious state should follow established ethical and legal principles and accepted practice guidelines of professional medical specialty societies.

Residual cognitive function in comatose, vegetative and minimally conscious states

PURPOSE OF REVIEW

The clinical evaluation of cognition in non-communicative severely brain-damaged patients is inherently difficult. In addition to novel behavioural 'consciousness-scales', the role of para-clinical markers of consciousness, such as event related potentials and functional neuroimaging is reviewed.

RECENT FINDINGS

New behavioural scales for vegetative and minimally conscious patients have been shown to reduce diagnostic error but regrettably remain underused in clinical routine. Electrophysiological studies have confirmed their role in estimating outcome and possibly cognition. Several recent functional neuroimaging studies have shown residual cortical function in undeniably vegetative patients. This cortical activation, however, seems limited to primary 'low-level' areas and does not imply 'higher-order' integration, considered necessary for conscious perception. Minimally conscious patients show large-scale high-order cerebral activation, apparently dependent upon the emotional relevance of the stimulation.

SUMMARY

Careful clinical assessment of putative 'conscious behaviour' in vegetative and minimally conscious patients is the first requirement for their proper diagnosis and management. Complementary functional neuroimaging and electrophysiological studies will have a major impact on future clinical decision making and may guide selective therapeutic options. At present, more experimental evidence and the elucidation of methodological and ethical controversies are awaited prior to their routine clinical use.