Spontaneous intermittent generalized attenuations (SIGAs) are defined as a transient decrease in amplitude of electroencephalography (EEG) activity in response to a physiologic process, external stimuli, or as a result of a pathologic condition. We seek to investigate their relationship to clinical outcomes. Demographic information, modified Rankin Scale (mRS), and clinical information were noted on 22 consecutive patients with SIGAs on their EEG. 12 of the 22 patients (54.5%) died, and 12 patients (54.5%) were admitted to the intensive care unit or coronary care unit. Future studies should attempt to prospectively compare outcomes among patients with SIGAs against a control group.

This article is concerned with patients in coma, the vegetative, or minimally conscious states. Studies addressing the issue of assessment and management of these patients are described. These include (a) the development of an assessment tool (Wessex Head Injury Matrix, WHIM); (b) use of the WHIM to assess the effects of posture on arousal, showing that some 75% of patients show more behaviours when assessed while they are in a standing frame than when supine; (c) a comparison of the WHIM with the Glasgow Coma Scale, demonstrating that the WHIM is more sensitive than the GCS for measuring the behavioural repertoire of people in states of reduced consciousness; (d) a discussion of situations when neuro-imaging techniques are required to assess residual functioning; and (e) the long term outcome of one of the first vegetative patients to be scanned with Positron Emission Tomography (PET). We conclude with a discussion about neuropsychology and patients in states of impaired consciousness.

Background: Delirium occurs frequently in the intensive care unit (ICU), but its pathophysiology is still unclear. Low levels of insulin-like growth factor 1 (IGF-1), a hormone with neuroprotective properties, have been associated with delirium in some non-ICU studies, but this relationship has not been examined in the ICU. We sought to test the hypothesis that low IGF-1 concentrations are associated with delirium during critical illness.

Methods: Mechanically ventilated medical ICU patients were prospectively enrolled, and blood was collected after enrollment for measurement of IGF-1 using radioimmunometric assay. Delirium and coma were identified daily using the Confusion Assessment Method for the ICU and the Richmond Agitation-Sedation Scale, respectively. The association between IGF-1 and delirium was evaluated with logistic regression. In addition, the association between IGF-1 and duration of normal mental state, measured as days alive without delirium or coma, was assessed using multiple linear regression.

Results: Among 110 patients, the median age was 65 years (IQR, 52–75) and APACHE II was 27 (IQR, 22 –32). IGF-1 levels were not a risk factor for delirium on the day after IGF-1 measurement (p = 0.97), at which time 65% of the assessable patients were delirious. No significant association was found between IGF-1 levels and duration of normal mental state (p = 0.23).

Conclusions: This pilot study, the first to investigate IGF-1 and delirium in critically ill patients, found no association between IGF-1 and delirium. Future studies including serial measurements of IGF-1 and IGF-1 binding proteins are needed to determine whether this hormone has a role in delirium during critical illness.

Postanoxic coma is a state of unconsciousness caused by global anoxia of the brain, most commonly due to cardiac arrest. Outcome after postanoxic coma lasting more than several hours is generally, but not invariably, poor. Recovery of consciousness reported in the literature varies from 8% to 72% of patients, but is mostly thought to be around 20–30% in patients surviving in coma for at least 24 h. Research is directed at defining factors that reliably predict poor outcome in these patients. Favourable outcome proves impossible to predict. Studies on outcome prediction have focussed mostly on neurological examination, clinical neurophysiological tests and biochemical parameters. The most recent and extensive study in this respect was the PROPAC study in The Netherlands (407 patients). This study confirmed earlier findings that bilaterally absent early cortical response after median nerve somatosensory potentials (absent somatosensory evoked potentials) is the most reliable predictor of poor outcome (no recovery of consciousness). A serum neuron-specific-enolase level >33 μg L−1 seemed equally reliable. In 2006, the American Practice Parameter on anoxic-ischaemic coma was published, summarizing the findings from the different studies. Poor outcome was defined as death, coma or severe disability after 6 months. The following factors were found to reliably predict this outcome: myoclonic status epilepticus within the first 24 h, absent pupillary responses after 24 h, absent corneal reflexes after 48 h, motor response to pain absent or extensor after 72 h and absent somatosensory evoked potentials (as defined above) after 1–3 days. Results for biochemical parameters (such as neuron-specific enolase) and neuroimaging are inconclusive.

NASA's Deep Space 1 (DSl) spacecraft successfully encountered comet 19P/Borrelly near perihelion and the Miniature Integrated Camera and Spectrometer (MICAS) imaging system onboard DS1 returned the first high-resolution images of a Jupiter-family comet nucleus and surrounding environment. The images span solar phase angles from 88° to 52°, providing stereoscopic coverage of the dust coma and nucleus. Numerous surface features are revealed on the 8-km long nucleus in the highest resolution images (47-58 m/pixel). A smooth, broad basin containing brighter regions and mesa-like structures is present in the central part of the nucleus that seems to be the source of jet-like dust features seen in the coma. High ridges seen along the jagged terminator lead to rugged terrain on both ends of the nucleus containing dark patches and smaller series of parallel grooves. No evidence of impact craters with diameters larger than about 200-m are present, indicating a young and active surface. The nucleus is very dark with albedo variations from 0.007 to 0.035. Short-wavelength, infrared spectra from 1.3 to 2.6 μm revealed a hot, dry surface consistent with less than about 10% actively sublimating. Two types of dust features are seen: broad fans and highly collimated “jets” in the sunward hemisphere that can be traced to the surface. The source region of the main jet feature, which resolved into at least three smaller “jets” near the surface, is consistent with an area around the rotation pole that is constantly illuminated by the sun during the encounter. Within a few nuclear radii, entrained dust is rapidly accelerated and fragmented and geometrical effects caused from extended source regions are present, as evidenced in radial intensity profiles centered on the jet features that show an increase in source strength with increasing cometocentric distance. Asymmetries in the dust from dayside to nightside are pronounced and may show evidence of lateral flow transporting dust to structures observed in the nightside coma. A summary of the initial results of the Deep Space 1 Mission is provided, highlighting the new knowledge that has been gained thus far.

Background and objective: Parallels exist between the coma associated with cerebral malaria and general anaesthesia. They both produce reversible loss of consciousness. In the case of cerebral malaria and in the absence of other complications, patients recover without sequelae. General anaesthetics are so designed that patients recover from their anaesthetics very quickly and show no ‘after effects’. This study compares brain function in these two clinical conditions by examining auditory- (AEPs) and median nerve somatosensory-evoked potentials (SEPs). The AEPs studied (waves Pa and Nb) are thought to arise from the primary auditory cortex and the median nerve SEPs (waves P15, N20, P25, N35, P45) from the pons, thalamus and primary somatosensory cortices.

Methods: Six comatosed patients with malaria (three males, three females) aged between 19 and 38 yr were studied in Zimbabwe. Their Glasgow Coma Scores on admission were 4, 3, 6, 7, 7 and 11. Their AEPs and median nerve SEPs were recorded daily over 4 days. The data were compared with those previously collected in the UK on patients and volunteers anaesthetized with desflurane, isoflurane, sevoflurane and propofol.

Results: In general, patients with cerebral malaria showed AEPs and SEPs similar to those of light to moderate anaesthesia i.e. 0.5–1.25 measure of anaesthetic potency (MAC), where 1 MAC is the minimum alveolar concentration necessary to prevent movement to surgical incision in 50% of patients. The appearance of the AEPs and SEPs bore no relationship to the degree of coma. The auditory brainstem-evoked response was retained in all degrees of coma, as would be expected. Otherwise, it would not be possible to interpret the waveform. In most instances, the early cortical complex Pa/Nb/Pb of the AER was present. When comatose patients emerged from malarial coma or were stimulated by talking loudly to them, they showed changes in the Pa/Nb/Pb complex similar to those seen on awakening from anaesthesia. The somatosensory-evoked response showed clear P15, N20 and P25 peaks at the expected latencies, and in some instances the waveforms of cerebral malaria and lightly anaesthetized volunteers were very similar.

Conclusions: The sensory-evoked responses of the cerebral malaria patients recorded in this study were not markedly different from those seen in light-to-moderately anaesthetized patients and volunteers. The profound depression of the AEPs and SEPs associated with deeper levels of anaesthesia were not seen, with the exception of one patient several hours before death.