References of "Moonen, Gustave"
     in
Bookmark and Share    
See detailp27(Kip1) as a master regulator of cortical neuron migration.
Godin, Juliette ULg; Thomas, Noémie; Laguesse, Sophie ULg et al

Poster (2012)

Detailed reference viewed: 3 (0 ULg)
Full Text
Peer Reviewed
See detailSudden sensorineural hearing loss: when ophthalmology meets otolaryngology.
Karelle, S.; Demanez, L.; Zangerle, P. F. et al

in B-ENT (2012), 8(2), 135-9

OBJECTIVES: Sudden sensorineural hearing loss is a perplexing entity in otology. Susac's syndrome (also called retinocochleocerebral vasculopathy) is a rare disorder that consists of microangiopathy of ... [more ▼]

OBJECTIVES: Sudden sensorineural hearing loss is a perplexing entity in otology. Susac's syndrome (also called retinocochleocerebral vasculopathy) is a rare disorder that consists of microangiopathy of the brain, retina, and inner ear, and usually affects women in young adulthood. We describe the clinical aspects, radiographic findings, and management of one such case. CASE REPORT: A 30-year-old woman was admitted to the hospital because of sudden onset of bilateral deafness and headache. During her hospitalization, she developed discrete right hemiparesis and hypoesthesia. RESULTS: Magnetic resonance imaging revealed multiple signal hyperintensities and atrophy of the corpus callosum. The differential diagnosis was a myelinating condition, such as multiple sclerosis or acute demyelinating encephalomyelitis. CONCLUSION: Retinal fluorescein angiography helped the diagnosis of Susac's syndrome. [less ▲]

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailCycling or not cycling: cell cycle regulatory molecules and adult neurogenesis.
Beukelaers, Pierre ULg; Vandenbosch, Renaud ULg; Caron, Nicolas ULg et al

in Cellular and Molecular Life Sciences : CMLS (2012), 69(9), 1493-1503

The adult brain most probably reaches its highest degree of plasticity with the lifelong generation and integration of new neurons in the hippocampus and olfactory system. Neural precursor cells (NPCs ... [more ▼]

The adult brain most probably reaches its highest degree of plasticity with the lifelong generation and integration of new neurons in the hippocampus and olfactory system. Neural precursor cells (NPCs) residing both in the subgranular zone of the dentate gyrus and in the subventricular zone of the lateral ventricles continuously generate neurons that populate the dentate gyrus and the olfactory bulb, respectively. The regulation of NPC proliferation in the adult brain has been widely investigated in the past few years. Yet, the intrinsic cell cycle machinery underlying NPC proliferation remains largely unexplored. In this review, we discuss the cell cycle components that are involved in the regulation of NPC proliferation in both neurogenic areas of the adult brain. [less ▲]

Detailed reference viewed: 49 (21 ULg)
Full Text
Peer Reviewed
See detailMicroRNAs tune cerebral cortical neurogenesis.
Volvert, M.-L.; Rogister, F.; Moonen, Gustave ULg et al

in Cell Death & Differentiation (2012), 19(10), 1573-81

MicroRNAs (miRNAs) are non-coding RNAs that promote post-transcriptional silencing of genes involved in a wide range of developmental and pathological processes. It is estimated that most protein-coding ... [more ▼]

MicroRNAs (miRNAs) are non-coding RNAs that promote post-transcriptional silencing of genes involved in a wide range of developmental and pathological processes. It is estimated that most protein-coding genes harbor miRNA recognition sequences in their 3' untranslated region and are thus putative targets. While functions of miRNAs have been extensively characterized in various tissues, their multiple contributions to cerebral cortical development are just beginning to be unveiled. This review aims to outline the evidence collected to date demonstrating a role for miRNAs in cerebral corticogenesis with a particular emphasis on pathways that control the birth and maturation of functional excitatory projection neurons. [less ▲]

Detailed reference viewed: 7 (3 ULg)
Full Text
Peer Reviewed
See detailp27(Kip1) Is a Microtubule-Associated Protein that Promotes Microtubule Polymerization during Neuron Migration.
Godin, Juliette ULg; Thomas, Noemie; Laguesse, Sophie ULg et al

in Developmental Cell (2012), 23(4), 729-44

The migration of cortical interneurons is characterized by extensive morphological changes that result from successive cycles of nucleokinesis and neurite branching. Their molecular bases remain elusive ... [more ▼]

The migration of cortical interneurons is characterized by extensive morphological changes that result from successive cycles of nucleokinesis and neurite branching. Their molecular bases remain elusive, and the present work describes how p27(Kip1) controls cell-cycle-unrelated signaling pathways to regulate these morphological remodelings. Live imaging reveals that interneurons lacking p27(Kip1) show delayed tangential migration resulting from defects in both nucleokinesis and dynamic branching of the leading process. At the molecular level, p27(Kip1) is a microtubule-associated protein that promotes polymerization of microtubules in extending neurites, thereby contributing to tangential migration. Furthermore, we show that p27(Kip1) controls actomyosin contractions that drive both forward translocation of the nucleus and growth cone splitting. Thus, p27(Kip1) cell-autonomously controls nucleokinesis and neurite branching by regulating both actin and microtubule cytoskeletons. [less ▲]

Detailed reference viewed: 36 (13 ULg)
Full Text
Peer Reviewed
See detailLa vignette diagnostique de l'étudiant.Syndrome du trou déchiré postérieur(foramen jugulaire)
Moonen, Vincent; PHAN BA, Remy ULg; Tshibanda, J F et al

in Revue Médicale de Liège (2012), 67(4), 210-214

Detailed reference viewed: 39 (0 ULg)
Full Text
Peer Reviewed
See detailFunctional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients.
Bruno, Marie-Aurélie ULg; Majerus, Steve ULg; Boly, Mélanie ULg et al

in Journal of Neurology (2012), 259(6), 1087-98

Patients in a minimally conscious state (MCS) show restricted signs of awareness but are unable to communicate. We assessed cerebral glucose metabolism in MCS patients and tested the hypothesis that this ... [more ▼]

Patients in a minimally conscious state (MCS) show restricted signs of awareness but are unable to communicate. We assessed cerebral glucose metabolism in MCS patients and tested the hypothesis that this entity can be subcategorized into MCS- (i.e., patients only showing nonreflex behavior such as visual pursuit, localization of noxious stimulation and/or contingent behavior) and MCS+ (i.e., patients showing command following).Patterns of cerebral glucose metabolism were studied using [(18)F]-fluorodeoxyglucose-PET in 39 healthy volunteers (aged 46 +/- 18 years) and 27 MCS patients of whom 13 were MCS- (aged 49 +/- 19 years; 4 traumatic; 21 +/- 23 months post injury) and 14 MCS+ (aged 43 +/- 19 years; 5 traumatic; 19 +/- 26 months post injury). Results were thresholded for significance at false discovery rate corrected p < 0.05.We observed a metabolic impairment in a bilateral subcortical (thalamus and caudate) and cortical (fronto-temporo-parietal) network in nontraumatic and traumatic MCS patients. Compared to MCS-, patients in MCS+ showed higher cerebral metabolism in left-sided cortical areas encompassing the language network, premotor, presupplementary motor, and sensorimotor cortices. A functional connectivity study showed that Broca's region was disconnected from the rest of the language network, mesiofrontal and cerebellar areas in MCS- as compared to MCS+ patients.The proposed subcategorization of MCS based on the presence or absence of command following showed a different functional neuroanatomy. MCS- is characterized by preserved right hemispheric cortical metabolism interpreted as evidence of residual sensory consciousness. MCS+ patients showed preserved metabolism and functional connectivity in language networks arguably reflecting some additional higher order or extended consciousness albeit devoid of clinical verbal or nonverbal expression. [less ▲]

Detailed reference viewed: 164 (10 ULg)
Full Text
Peer Reviewed
See detailA corrected version of the Timed-25 Foot Walk Test with a dynamic start to capture the maximum ambulation speed in multiple sclerosis patients
Phan-Ba, Rémy ULg; CALAY, Philippe ULg; GRODENT, Patrick ULg et al

in NeuroRehabilitation (2012), 30(4), 261-266

Background : No clinical test is currently available and validated to measure the maximum walking speed (WS) of multiple sclerosis (MS) patients. Since the Timed 25-Foot Walk Test (T25FW) is performed ... [more ▼]

Background : No clinical test is currently available and validated to measure the maximum walking speed (WS) of multiple sclerosis (MS) patients. Since the Timed 25-Foot Walk Test (T25FW) is performed with a static start, it takes a significant proportion of the distance for MS patients to reach their maximum pace. Objectives : In order to capture the maximum WS and to quantify the relative impact of the accelerating phase during the first meters, we compared the classical T25FW with a modified version (T25FW+) allowing a dynamic start after a 3 meters run-up. Methods : Sixty-four MS patients and 30 healthy subjects performed successively the T25FW and the T25FW+. Results : The T25FW+ was performed faster than the T25FW for the vast majority of MS and healthy subjects. In the MS population, the mean relative gain of speed due to the dynamic start on T25FW+ was independent from the EDSS and from the level of ambulation impairment. Compared to healthy subjects, the relative difference between dynamic versus static start was more important in the MS population even in patients devoid of apparent gait impairment according to the T25FW. Conclusion : The T25FW+ allows a more accurate measurement of the maximum WS of MS patients, which is a prerequisite to reliably evaluate deceleration over longer distance tests. Indirect arguments suggest that the time to reach the maximum WS may be partially influenced by the cognitive impairment status. The maximum WS and the capacity of MS patients to accelerate on a specific distance may be independently regulated and assessed separately in clinical trials and rehabilitation programs. [less ▲]

Detailed reference viewed: 113 (34 ULg)
Full Text
Peer Reviewed
See detailVitamin D tweets light to genes in multiple sclerosis
LOMMERS, Emilie ULg; Lecrompe, Laurence ULg; Moonen, Gustave ULg et al

in Revue Médicale de Liège (2012), 67(5-6), 359-365

The relationship between sunlight exposure and the incidence of multiple sclerosis and the understanding of immunomodulatory effects of vitamin D triggered, in recent years, a broad range of ... [more ▼]

The relationship between sunlight exposure and the incidence of multiple sclerosis and the understanding of immunomodulatory effects of vitamin D triggered, in recent years, a broad range of investigations. Immunological studies performed in vitro and in vivo have demonstrated how tolerogenic vitamin D can be. Epidemiological studies confirmed an increased incidence of multiple sclerosis in vitamin D deficient subjects and signs of increased disease activity in such MS patients. Although small-scale observational studies have suggested a beneficial impact of vitamin D supplementation on the incidence and severity of multiple sclerosis, large scale clinical trials remain warranted to confirm these preliminary results. [less ▲]

Detailed reference viewed: 68 (14 ULg)
Full Text
Peer Reviewed
See detailPartial trisomy 4q associated with young-onset dopa-responsive parkinsonism.
Garraux, Gaëtan ULg; CABERG, Jean-Hubert ULg; Vanbellinghen, Jean-Francois et al

in Archives of Neurology (2012), 69(3), 398-400

OBJECTIVE: To describe a patient who developed a young-onset, dopa-responsive parkinsonism linked to a de novo heterozygous interstitial duplication 4q. DESIGN: Case report. SETTING: Movement Disorder ... [more ▼]

OBJECTIVE: To describe a patient who developed a young-onset, dopa-responsive parkinsonism linked to a de novo heterozygous interstitial duplication 4q. DESIGN: Case report. SETTING: Movement Disorder Outpatient Clinic at the University Hospital Centre, Liege, Belgium. Patient A 31-year-old woman. MAIN OUTCOME MEASURES: Clinical, neuroimaging, and genetic data. RESULTS: The duplicated region contains 150 known genes, including the alpha-synuclein (SNCA) gene locus. Motor and 6-[(18)F]fluoro-L-dopa positron emission tomography features are similar to those previously reported in heterozygote SNCA duplication carriers. Altered expression of other genes contained in the duplicated region may contribute to clinical features that are uncommon in the phenotypic spectrum of SNCA multiplications such as delayed developmental psychomotor milestones during infancy and musculoskeletal abnormalities. CONCLUSION: This case report provides new insights on the genetic basis of parkinsonism. [less ▲]

Detailed reference viewed: 32 (10 ULg)
Full Text
Peer Reviewed
See detailMRI preclinical detection and asymptomatic course of a progressive multifocal leucoencephalopathy (PML) under natalizumab therapy.
Phan-Ba, Rémy ULg; LOMMERS, Emilie ULg; TSHIBANDA, Luaba ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (2012), 83

Early detection of progressive multifocal leucoencephalopathy (PML) in the setting of natalizumab therapy currently is performed by rapid evaluation of new symptoms occurring in treated patients. The role ... [more ▼]

Early detection of progressive multifocal leucoencephalopathy (PML) in the setting of natalizumab therapy currently is performed by rapid evaluation of new symptoms occurring in treated patients. The role of MR scanning has not been investigated but holds promise since MR detection is highly sensitive for PML lesions. The authors report a case of presymptomatic PML of the posterior fossa detected by MR scans. Immediate suspension of natalizumab and plasma exchanges resulted in a rapid decline of natalizumab serum concentration. Intravenous steroids started together with plasma exchanges followed by an oral tapering course were used to minimise the immune reconstitution inflammatory syndrome. No symptoms (beyond mild headache) developed, and the repeat PCR for JC Virus (JCV) DNA detection performed 10 weeks later was negative. This case suggests that: (1) periodic brain MR scans may detect signs of presymptomatic PML in MS patients treated with natalizumab, (2) corticosteroid management of inflammatory reaction may contribute to optimal control of the immune reconstitution inflammatory syndrome routinely seen with natalizumab-associated PML and (3) early radiological detection of PML can have an excellent outcome even in a clinically critical region and despite prior immunosuppressant exposure. The potential benefit of regular MR scanning just using the T2/FLAIR modalities could be further investigated in order to detect early natalizumab-associated PML, leading to benign outcomes. [less ▲]

Detailed reference viewed: 35 (6 ULg)
See detailp27(Kip1) as a master regulator of cortical neuron migration
Godin, Juliette ULg; Thomas, Noémie; Laguesse, Sophie ULg et al

Scientific conference (2011, June)

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailPrimary central nervous system lymphoma in a patient treated with Natalizumab.
Phan-Ba, Rémy ULg; Bisig, Bettina ULg; Deprez, Manuel ULg et al

in Annals of Neurology (2011), 69(6), 1060-1

Detailed reference viewed: 42 (13 ULg)
Full Text
Peer Reviewed
See detailAutomated EEG entropy measurements in coma, vegetative state/unresponsive wakefulness syndrome and minimally conscious state
Gosseries, Olivia ULg; Schnakers, Caroline ULg; LEDOUX, Didier ULg et al

in Functional Neurology (2011)

Monitoring the level of consciousness in brain injured patients with disorders of consciousness is crucial as it provides diagnostic and prognostic information. Behavioral assessment remains the gold ... [more ▼]

Monitoring the level of consciousness in brain injured patients with disorders of consciousness is crucial as it provides diagnostic and prognostic information. Behavioral assessment remains the gold standard for assessing consciousness but previous studies have shown a high rate of misdiagnosis. This study aimed to investigate the usefulness of electroencephalography (EEG) entropy measurements in differentiating unconscious (coma or vegetative) from minimally conscious patients. Left fronto-temporal EEG recordings (10-minute resting state epochs) were prospectively obtained in 56 patients and 16 age-matched healthy volunteers. Patients were assessed in the acute (≤1 month post-injury;n=29) or chronic (>1 month post-injury; n=27) stage. The etiology was traumatic in 23 patients. Automated online EEG entropy calculations (providing an arbitrary value ranging from 0 to 91) were compared with behavioral assessments (Coma Recovery Scale-Revised) and outcome. EEG entropy correlated with Coma Recovery Scale total scores (r=0.49). Mean EEG entropy values were higher in minimally conscious (73±19; mean and standard deviation) than in vegetative/unresponsive wakefulness syndrome patients (45±28). Receiver operating characteristic analysis revealed an entropy cut-off value of 52 differentiating acute unconscious from minimally conscious patients (sensitivity 89% and specificity 90%). In chronic patients, entropy measurements offered no reliable diagnostic information. EEG entropy measurements did not allow prediction of outcome. User-independent time-frequency balanced spectral EEG entropy measurements seem to constitute an interesting diagnostic – albeit not prognostic – tool for assessing neural network complexity in disorders of consciousness in the acute setting. Future studies are needed before using this tool in routine clinical practice, and these should seek to improve automated EEG quantification paradigms in order to reduce the remaining false negative and false positive findings. [less ▲]

Detailed reference viewed: 244 (11 ULg)
Full Text
Peer Reviewed
See detailRadiation-induced malignant peripheral nerve sheat tumors – a report of 2 cases
PHAN BA, Remy ULg; BELACHEW, Shibeshih ULg; JEDIDI, Zayd ULg et al

Poster (2011, May)

We discuss the case of two patients who developped delayed malignant peripheral nerve sheath tumor (MPNST) following radiotherapy. Case report: the first patient is a sixty year-old woman with a 2 years ... [more ▼]

We discuss the case of two patients who developped delayed malignant peripheral nerve sheath tumor (MPNST) following radiotherapy. Case report: the first patient is a sixty year-old woman with a 2 years history of right cervicobrachial pain and weakness. The neurological examination depicted severe weakness, atrophy and loss of sensation in the right C5 and C6 territories. A subclavicular hardened and enlarged lymph node was noted. Her past medical history was notable for a Hodgkin’s disease (HD) treated with radiation therapy (>40Gy) 35 years earlier. Brachial plexus MRI revealed a tumoral mass arising from the right brachial plexus. Biopsy of the subclavicular mass revealed a poorly differentiated malignant tumour consisting of spindle cells showing moderate polymorphism and a high mitotic index. Immunohistochemistry showed positivity for the S-100 protein, the CD56 and for the epithelial membrane antigen (EMA) and a diagnosis of MPNST of the brachial plexus was proposed. The second case is a 36 year-old man referred for a history of right sciatic neuralgia that appeared 3 years earlier. The medical history of the patient was notable for a right seminoma, treated by orchidectomy and prophylactic radiotherapy (24 Gy) 5 years earlier. The neurologic examination revealed right L5 and S1 radicular territories involvement, and the CT of the pelvis demonstrated a nodular mass at the level of the greater sciatic foramen. A surgical biopsy was performed and the neuropathological findings were consistent with a diagnosis of low-grade MPSNT. Discussion: MPNSTs are rare tumors accounting for 3 to 10% of all tissues sarcomas. Half of the cases described are sporadic, while the other half tend to appear in patients suffering from tumor prone conditions, such as neurofibromatosis type 1. Although secondary neoplasms are known complications of radiotherapy, descriptions of peripheral nerve sheath tumors (PNST) are scarce. The exact pathophysiology of radiation-induced PNSTs remains unclear but vascular alterations, direct damages to axon or Schwann cell and nerve compression by soft tissue fibrosis are thought to play a role. Although surgical removal sometimes followed by chemotherapy is the mainstay of MPNSTs, they usually carry a poor prognosis. Our 2 cases emphasize that the possibility of radiation-induced MPNST has to be kept in mind when investigating a localized neuropathy in a previously irradiated area. [less ▲]

Detailed reference viewed: 30 (4 ULg)
Full Text
Peer Reviewed
See detailComparison of the Timed 25-Foot and the 100-Meter Walk as Performance Measures in Multiple Sclerosis
Phan-Ba, Rémy ULg; Pace, Amy; CALAY, Philippe ULg et al

in Neurorehabilitation and neural repair (2011), 25(7), 672-9

BACKGROUND: Ambulation impairment is a major component of physical disability in multiple sclerosis (MS) and a major target of rehabilitation programs. Outcome measures commonly used to evaluate walking ... [more ▼]

BACKGROUND: Ambulation impairment is a major component of physical disability in multiple sclerosis (MS) and a major target of rehabilitation programs. Outcome measures commonly used to evaluate walking capacities suffer from several limitations. OBJECTIVES: To define and validate a new test that would overcome the limitations of current gait evaluations in MS and ultimately better correlate with the maximum walking distance (MWD). METHODS: The authors developed the Timed 100-Meter Walk Test (T100MW), which was compared with the Timed 25-Foot Walk Test (T25FW). For the T100MW, the subject is invited to walk 100 m as fast as he/she can. In MS patients and healthy control volunteers, the authors measured the test-retest and interrater intraclass correlation coefficient. Spearman rank correlations were obtained between the T25FW, the T100MW, the Expanded Disability Status Scale (EDSS), and the MWD. The coefficient of variation, Bland-Altman plots, the coefficient of determination, and the area under the receiver operator characteristic curve were measured. The mean walking speed (MWS) was compared between the 2 tests. RESULTS: A total of 141 MS patients and 104 healthy control volunteers were assessed. Minor differences favoring the T100MW over the T25FW were observed. Interestingly, the authors demonstrated a paradoxically higher MWS on a long (T100MW) rather than on a short distance walk test (T25FW). CONCLUSION: The T25FW and T100MW displayed subtle differences of reproducibility, variability, and correlation with MWD favoring the T100MW. The maximum walking speed of MS patients may be poorly estimated by the T25FW since MS patients were shown to walk faster over a longer distance. [less ▲]

Detailed reference viewed: 121 (45 ULg)
Full Text
Peer Reviewed
See detailCdk6-dependent regulation of g(1) length controls adult neurogenesis.
Beukelaers, Pierre; Vandenbosch, Renaud ULg; Caron, Nicolas ULg et al

in Stem Cells (2011), 29(4), 713-24

The presence of neurogenic precursors in the adult mammalian brain is now widely accepted, but the mechanisms coupling their proliferation with the onset of neuronal differentiation remain unknown. Here ... [more ▼]

The presence of neurogenic precursors in the adult mammalian brain is now widely accepted, but the mechanisms coupling their proliferation with the onset of neuronal differentiation remain unknown. Here, we unravel the major contribution of the G(1) regulator cyclin-dependent kinase 6 (Cdk6) to adult neurogenesis. We found that Cdk6 was essential for cell proliferation within the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricles. Specifically, Cdk6 deficiency prevents the expansion of neuronally committed precursors by lengthening G(1) phase duration, reducing concomitantly the production of newborn neurons. Altogether, our data support G(1) length as an essential regulator of the switch between proliferation and neuronal differentiation in the adult brain and Cdk6 as one intrinsic key molecular regulator of this process. STEM Cells 2011;29:713-724. [less ▲]

Detailed reference viewed: 57 (30 ULg)
Full Text
Peer Reviewed
See detailFrom unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: recent advances in our understanding of disorders of consciousness.
Bruno, Marie-Aurélie ULg; Vanhaudenhuyse, Audrey ULg; Thibaut, Aurore ULg et al

in Journal of Neurology (2011), 258(7), 1373-84

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 ... [more ▼]

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. [less ▲]

Detailed reference viewed: 17 (3 ULg)
Full Text
Peer Reviewed
See detail"Relevance vector machine" consciousness classifier applied to cerebral metabolism of vegetative and locked-in patients.
Phillips, Christophe ULg; Bruno, Marie-Aurélie ULg; Maquet, Pierre ULg et al

in NeuroImage (2011), 56(2), 797808

The vegetative state is a devastating condition where patients awaken from their coma (i.e., open their eyes) but fail to show any behavioural sign of conscious awareness. Locked-in syndrome patients also ... [more ▼]

The vegetative state is a devastating condition where patients awaken from their coma (i.e., open their eyes) but fail to show any behavioural sign of conscious awareness. Locked-in syndrome patients also awaken from their coma and are unable to show any motor response to command (except for small eye movements or blinks) but recover full conscious awareness of self and environment. Bedside evaluation of residual cognitive function in coma survivors often is difficult because motor responses may be very limited or inconsistent. We here aimed to disentangle vegetative from "locked-in" patients by an automatic procedure based on machine learning using fluorodeoxyglucose PET data obtained in 37 healthy controls and in 13 patients in a vegetative state. Next, the trained machine was tested on brain scans obtained in 8 patients with locked-in syndrome. We used a sparse probabilistic Bayesian learning framework called "relevance vector machine" (RVM) to classify the scans. The trained RVM classifier, applied on an input scan, returns a probability value (p-value) of being in one class or the other, here being "conscious" or not. Training on the control and vegetative state groups was assessed with a leave-one-out cross-validation procedure, leading to 100% classification accuracy. When applied on the locked-in patients, all scans were classified as "conscious" with a mean p-value of .95 (min .85). In conclusion, even with this relatively limited data set, we could train a classifier distinguishing between normal consciousness (i.e., wakeful conscious awareness) and the vegetative state (i.e., wakeful unawareness). Cross-validation also indicated that the clinical classification and the one predicted by the automatic RVM classifier were in accordance. Moreover, when applied on a third group of "locked-in" consciously aware patients, they all had a strong probability of being similar to the normal controls, as expected. Therefore, RVM classification of cerebral metabolic images obtained in coma survivors could become a useful tool for the automated PET-based diagnosis of altered states of consciousness. [less ▲]

Detailed reference viewed: 40 (11 ULg)