The evaluation of the level of consciousness in patients with disorders of consciousness (DOC) is primarily based on behavioural assessments. Patients with unresponsive wakefulness syndrome (UWS) do not show any sign of awareness of their environment, while minimally conscious state (MCS) patients show reproducible but fluctuating signs of awareness. Some patients, although with remaining cognitive abilities, are not able to exhibit overt voluntary responses at the bedside and may be misdiagnosed as UWS. Several studies investigated functional neuroimaging and neurophysiology as an additional tool to evaluate the level of consciousness and to detect covert command following in DOC. Most of these studies are based on auditory stimulation, neglecting patients suffering from decreased or absent hearing abilities. In the present study, we aim to assess the response to a P3-based paradigm in 40 patients with DOC and 12 healthy participants using auditory (AEP) and vibrotactile (VTP) stimulation. To this end, an EEG-based brain-computer interface was used at DOC patient’s bedside. We compared the significance of the P3 performance (i.e., the interpretation of significance of the evoked P3 response) as obtained by ‘direct processing’ (i.e., theoretical-based significance threshold) and ‘offline processing’ (i.e., permutation-based single subject level threshold). We evaluated whether the P3 performances were dependent on clinical variables such as diagnosis (UWS and MCS), aetiology and time since injury. Last we tested the dependency of AEP and VTP performances at the single subject level. Direct processing tends to overestimate P3 performance. We did not find any difference in the presence of a P3 performance according to the level of consciousness (UWS vs. MCS) or the aetiology (traumatic vs. non-traumatic brain injury). The performance achieved at the AEP paradigm was independent from what was achieved at the VTP paradigm, indicating that some patients performed better on the AEP task while others performed better on the VTP task. Our results support the importance of using multimodal approaches in the assessment of DOC patients in order to optimise the evaluation of patient’s abilities.
ZusammenfassungDigital angebotene psychologische Interventionen gegen Schlafstörungen sind aktuell ein sehr intensiv bearbeitetes Forschungsthema. In dieser Übersichtsarbeit werden Originalarbeiten und Metaanalysen zu diesem Thema zusammengefasst. Hierbei zeigt sich, dass die internetbasierte kognitive Verhaltenstherapie für Insomnie (KVT-I) bei Erwachsenen durchweg sehr effektiv ist mit allenfalls leicht geringeren Effektstärken als die gleiche Behandlung mit physischer Präsenz von Therapeuten und Patienten. Behandlungseffekte zeigen sich dabei auch für sekundäre Outcome-Parameter wie Depressivität, Angst, Fatigue und Lebensqualität. Hingegen lassen die Forschung zur Wirksamkeit der internetbasierten KVT‑I bei Erwachsenen mit komorbiden psychischen Störungen oder körperlichen Erkrankungen sowie die Forschung zur Frage, wieviel Therapeutenkontakt in die Behandlung integriert werden sollte, anscheinend noch keine abschließenden Antworten zu. In diesen Bereichen scheint weitere Forschung notwendig zu sein scheint.
Background Sleep-wakefulness cycles are an essential diagnostic criterion for disorders of consciousness (DOC), differentiating prolonged DOC from coma. Specific sleep features, like the presence of sleep spindles, are an important marker for the prognosis of recovery from DOC. Based on increasing evidence for a link between sleep and neuronal plasticity, understanding sleep in DOC might facilitate the development of novel methods for rehabilitation. Yet, well-controlled studies of sleep in DOC are lacking. Here, we aimed to quantify, on a reliable evaluation basis, the distribution of behavioral and neurophysiological sleep patterns in DOC over a 24-h period while controlling for environmental factors (by recruiting a group of conscious tetraplegic patients who resided in the same hospital). Methods We evaluated the distribution of sleep and wakefulness by means of polysomnography (EEG, EOG, EMG) and video recordings in 32 DOC patients (16 unresponsive wakefulness syndrome [UWS], 16 minimally conscious state [MCS]), and 10 clinical control patients with severe tetraplegia. Three independent raters scored the patients’ polysomnographic recordings. Results All but one patient (UWS) showed behavioral and electrophysiological signs of sleep. Control and MCS patients spent significantly more time in sleep during the night than during daytime, a pattern that was not evident in UWS. DOC patients (particularly UWS) exhibited less REM sleep than control patients. Forty-four percent of UWS patients and 12% of MCS patients did not have any REM sleep, while all control patients (100%) showed signs of all sleep stages and sleep spindles. Furthermore, no sleep spindles were found in 62% of UWS patients and 21% of MCS patients. In the remaining DOC patients who had spindles, their number and amplitude were significantly lower than in controls. Conclusions The distribution of sleep signs in DOC over 24 h differs significantly from the normal sleep-wakefulness pattern. These abnormalities of sleep in DOC are independent of external factors such as severe immobility and hospital environment.
Objectives: To quantify, on a reliable evaluation basis, the distribution of behavioral and neurophysiological sleep patterns in Disorders of Consciousness (DOC) over a 24h period while controlling for environmental factors (by recruiting a group of conscious tetraplegic patients who resided in the same hospital). Methods: We evaluated the distribution of sleep and wakefulness by means of polysomnography (EEG, EOG, EMG) and video recordings in 32 DOC patients (16 Unresponsive Wakefulness Syndrome [UWS], 16 Minimally Conscious State [MCS]) and 10 clinical control patients with severe tetraplegia (CC). Three independent raters scored the patients' polysomnographic recordings. Results: All but one patient (UWS) showed behavioral and electrophysiological signs of sleep. CC and MCS patients spent significantly more time in sleep during the night than during daytime, a pattern that was not evident in UWS. DOC patients (particularly UWS) exhibited less REM sleep than control patients. 44% of UWS patients and 12% of MCS patients did not have any REM sleep, while all control patients (100%) showed signs of all sleep stages and sleep spindles. Furthermore, no sleep spindles were found in 62% of UWS patients and 21% of MCS patients. In the remaining DOC patients who had spindles, their number and amplitude were significantly lower than in controls. Interpretation: The distribution of sleep signs in DOC over 24 hours differs significantly from the normal sleep-wakefulness pattern. These abnormalities of sleep in DOC are independent of external factors such as severe immobility and hospital environment.
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