Defining consciousness: lessons from patients and modern techniques

Translation and Transcultural Adaptation of the Wessex Head Injury Matrix, Italian Version: A Preliminary Report

Background: Patients who are in a coma, a vegetative state or a minimally conscious state present a clinical challenge for neurological assessment, which is a prerequisite for establishing a prognosis and planning management. Several scales have been developed to evaluate these patients. The Wessex Head Injury Matrix is a comprehensive tool but is currently available only in the French and English languages. The aim of this study was to translate and evaluate the reliability of the Italian version of the scale. Methods: The original scale was translated according to a standard protocol: three separate translations were made, and a selected version was back-translated to check for any errors in order to obtain the most accurate Italian translation. A final back translation of the agreed version was made as a further check. The final version was then administered blind to a consecutive series of patients with severe acquired brain injury by two examiners. Inter-rater and test-retest reliability were assessed using a weighted Cohen’s kappa (Kw). Concurrent validity of the WHIM was evaluated by ρ Spearman’s correlation coefficient using the Glasgow Coma Scale (GCS) and the Coma Recovery Scale Revised (CRS-R) as the available gold standard. Results: Twenty-four patients (12 males and 12 females; mean age 59.9 ± 20.1; mean duration from index event 17.7 ± 20.0 days) with stroke (n = 15), traumatic brain injury (n = 7) and anoxic encephalopathy (n = 2) were included. Inter-rater [Kw 0.80 (95% CI 0.75–0.84)] and test-retest reliability [Kw 0.77 (95% CI 0.72–0.81)] showed good values. WHIM total scores correlated significantly with total scores on the GCS (ρ = 0.776; p < 0.001) and the CRS-R (ρ = 0.881; p < 0.001) demonstrating concurrent validity; Conclusion: The Italian version of the scale is now available for clinical practice and research.

Disorders of Consciousness: Painless or Painful Conditions?-Evidence from Neuroimaging Studies

The experience of pain in disorders of consciousness is still debated. Neuroimaging studies, using functional Magnetic Resonance Imaging (fMRI), Positron Emission Tomography (PET), multichannel electroencephalography (EEG) and laser-evoked potentials, suggest that the perception of pain increases with the level of consciousness. Brain activation in response to noxious stimuli has been observed in patients with unresponsive wakefulness syndrome (UWS), which is also referred to as a vegetative state (VS), as well as those in a minimally conscious state (MCS). However, all of these techniques suggest that pain-related brain activation patterns of patients in MCS more closely resemble those of healthy subjects. This is further supported by fMRI findings showing a much greater functional connectivity within the structures of the so-called pain matrix in MCS as compared to UWS/VS patients. Nonetheless, when interpreting the results, a distinction is necessary between autonomic responses to potentially harmful stimuli and conscious experience of the unpleasantness of pain. Even more so if we consider that the degree of residual functioning and cortical connectivity necessary for the somatosensory, affective and cognitive-evaluative components of pain processing are not yet clear. Although procedurally challenging, the particular value of the aforementioned techniques in the assessment of pain in disorders of consciousness has been clearly demonstrated. The study of pain-related brain activation and functioning can contribute to a better understanding of the networks underlying pain perception while addressing clinical and ethical questions concerning patient care. Further development of technology and methods should aim to increase the availability of neuroimaging, objective assessment of functional connectivity and analysis at the level of individual cases as well as group comparisons. This will enable neuroimaging to truly become a clinical tool to reliably investigate pain in severely brain-injured patients as well as an asset for research.

An Innovative Model of a Home-Like Environment for People in Vegetative and Minimally Conscious States

BACKGROUND AND PURPOSE

Many forms of assisted living have been proposed for people who have a loss of autonomy in activities of daily living. Despite the increasing prevalence of vegetative and minimally conscious states, no dedicated residential accommodation has been implemented for patients with chronic disorders of consciousness (DOCs).

METHODS

This is a descriptive study addressing an innovative model of in-house assistance, named Casa Iride, which has recently been implemented in the attempt to ensure health, safety, and well-being for people with DOCs and their families.

RESULTS

Our findings show that Casa Iride enables severely disabled individuals to live with dignity within a customized domestic environment. At the same time, it provides support for caregivers from both a practical and a psychological point of view.

CONCLUSIONS

The results so far indicate a virtuous cycle that brings health, social, psychological, ethical, and economic advantages: the individuals receive all the assistance needed; the families share a place with other people with similar challenges, become more aware of their situation, and learn to cope with it and to maintain their productivity at work; and the care flow of patients through intensive care units and intensive rehabilitation wards is not delayed by a lack of post discharge services.

Intrathecal baclofen: effects on spasticity, pain, and consciousness in disorders of consciousness and locked-in syndrome

Disorders of consciousness (DOCs) include coma, vegetative state (VS), and minimally conscious state (MCS). Coma is characterized by impaired wakefulness and consciousness, while VS and MCS are defined by lacking or discontinuous consciousness despite recovered wakefulness. Conversely, locked-in syndrome (LIS) is characterized by quadriplegia and lower cranial nerve paralysis with preserved consciousness. Intrathecal baclofen (ITB) is a useful treatment to improve spasticity both in patients with DOCs and LIS. Moreover, it supports the recovery of consciousness in some patients with VS or MCS. The precise mechanism underlying this recovery has not yet been elucidated. It has been hypothesized that ITB may act by reducing the overload of dysfunctional sensory stimuli reaching the injured brain or by stabilizing the imbalanced circadian rhythms. Although the current indication of ITB is the management of severe spasticity, its potential use in speeding the recovery of consciousness merits further investigation.

The perception of pain and its management in disorders of consciousness

One of the most controversial issues in the management of patients in a vegetative state or a minimally conscious state concerns their hypothetical capacity to continue to experience pain despite an apparent absence of self- and environmental awareness. Recent functional neuroimaging studies have shown a greater perception of pain in patients in minimally conscious state compared with patients in vegetative state, suggesting the possible involvement of preserved cognitive mechanisms in the process of pain modulation in the former. In addition, a subgroup of patients might continue to experience some elementary emotional and affective feelings, as suggested by the reported activation of specific cerebral areas in response to situations, which commonly generate empathy. However, the available evidence is not sufficient to draw conclusions about the presence or absence of pain experience in patients with disorders of consciousness. Future studies should contribute to a better understanding of which central neural pathways are involved in the perception and modulation of pain in healthy subjects and in patients with severe brain injuries. Such studies should thus also improve our know-how about pain management in this particularly challenging group of patients.

Awakenings and awareness recovery in disorders of consciousness: is there a role for drugs?

Disorders of consciousness (DOC) include coma, vegetative state (VS) and minimally conscious state (MCS). Coma is a condition of unarousability with a complete absence of wakefulness and awareness, whereas VS is characterized by a lack of awareness despite a preserved wakefulness. Patients in coma are unconscious because they lack both wakefulness and awareness. Patients in a VS are unconscious because, although they are wakeful, they lack awareness. Patients in a MCS show minimal but definite behavioural evidence of self and environmental awareness. Coma results from diffuse bilateral hemispheric lesions or selective damage to the ascending reticular system (which is functionally connected to the cerebral cortex by intralaminar thalamic nuclei). VS is a syndrome that is considered to be the result of a disconnection of different cortical networks rather than a dysfunction of a single area or a global reduction in cortical metabolism. As revealed by functional imaging studies, clinical recovery is often associated with a functional restoration of cortico-thalamo-cortical connections. Depending on the amount of network restored, patients may regain full consciousness or remain in a MCS. Molecular and neural mediators may indirectly contribute to the above restoration processes owing to their role in the phenomenon of neural synaptic plasticity. Therefore, there is growing interest in the possible effects of drugs that act at the level of the CNS in promoting emergence from DOC. Sporadic cases of dramatic recovery from DOC after the administration of various pharmacological agents, such as baclofen, zolpidem and amantadine, have been recently supported by intriguing scientific observations. Analysis of the reported cases of recovery, with particular attention paid to the condition of the patients and to the association of their improvement with the start of drug administration, suggests that these treatments might have promoted the clinical improvement of some patients. These drugs are from various and diverging classes, but can be grouped into two main categories, CNS stimulants and CNS depressants. Some of these treatments seem to directly encourage a consciousness restoration, while others play a more determinant role in improving cognitive domains, especially in patients with residual cognitive impairment, than in the field of consciousness. Given the great interest recently generated in the scientific community by the increasing number of papers addressing this issue, further investigation of the above treatments, with particular attention paid to their mechanisms of action, the neurotransmitters involved and their effects on cortico-thalamo-cortical circuitry, is needed.

Intrathecal administration of GABA agonists in the vegetative state

Gamma aminobutyric acid (GABA) is an inhibitor neurotransmitter that plays many important roles in the central nervous system. Because the half-life time of GABA is very short in vivo, GABA itself is not used for clinical practice. An analogue of GABA, baclofen, is an agonist of GABA-B receptor, and has very strong antispastic effect by acting to the posterior horn of the spinal cord. However, baclofen poorly crosses through the blood brain barrier, and the antispastic effect is modest when administered orally. Therefore, direct continuous infusion of small doses of baclofen into the cerebrospinal fluid (intrathecal baclofen therapy, ITB) has become an established treatment for control of otherwise intractable severe spasticity. Spasticity is clinically defined as hypertonic state of the muscles with increased tendon reflexes, muscles spasm, spasm pain, abnormal posture, and limitation of involuntary movements. Spasticity is a common symptom after damage mainly to the pyramidal tract system in the brain or the spinal cord. Such damage is caused by traumatic brain injury, stroke, spinal cord injury, multiple sclerosis, and so on. Patients in persistent vegetative state (PVS) usually have diffuse and widespread damage to the brain, spasticity is generally seen in such patients. Control of spasticity may become important in the management of PVS patients in terms of nursing care, pain relief, and hygiene, and ITB may be indicated. Among PVS patients who had ITB to control spasticity, sporadic cases of dramatic recovery from PVS after ITB have been reported worldwide. The mechanism of such recovery of consciousness is poorly understood, and it may simply be a coincidence. On the other hand, electrical spinal cord stimulation (SCS) has been tried for many years in many patients in PVS, and some positive effects on recovery of consciousness have been reported. SCS is usually indicated for control of neuropathic pain, but it has also antispastic effect. The mechanism of SCS on pain is known to be mediated through the spinal GABA neuronal system. Thus, ITB and SCS have a common background, spinal GABA neuronal mechanism. The effect of GABA agonists on recovery of consciousness is not yet established, but review of such case studies becomes a clue to solve problems in PVS, and there may be hidden serendipity.