Stéphanie Mazza

Bio: Stéphanie Mazza is an academic researcher from French Institute of Health and Medical Research. The author has contributed to research in topics: Humanities & Obstructive sleep apnea. The author has an hindex of 17, co-authored 30 publications receiving 1371 citations. Previous affiliations of Stéphanie Mazza include Université de Montréal & Joseph Fourier University.

Rapid-eye-movement sleep behaviour disorder and neurodegenerative diseases

Abstract: Summary Rapid-eye-movement (REM) sleep behaviour disorder (RBD) is characterised by loss of muscular atonia and prominent motor behaviours during REM sleep RBD can cause sleep disruption and severe injuries for the patient or bed partner The disorder is strongly associated with neurodegenerative diseases, such as multiple-system atrophy, Parkinson's disease, dementia with Lewy bodies, and progressive supranuclear palsy In many cases, the symptoms of RBD precede other symptoms of these neurodegenerative disorders by several years Furthermore, several recent studies have shown that RBD is associated with abnormalities of electroencephalographic activity, cerebral blood flow, and cognitive, perceptual, and autonomic functions RBD might be a stage in the development of neurodegenerative disorders and increased awareness of this could lead to substantial advances in knowledge of mechanisms, diagnosis, and treatment of neurodegenerative disorders

Most obstructive sleep apnoea patients exhibit vigilance and attention deficits on an extended battery of tests.

Abstract: Excessive daytime sleepiness, fatigue and altered attention are often experienced by obstructive sleep apnoea (OSA) patients. Although attentional problems are presumably responsible for part of the daytime functioning impairment in OSA, thorough investigation is unusual. Clinicians usually attribute these symptoms to somnolence. In clinical practice, only one isolated test is generally used to assess vigilance and attentional defects. It was hypothesised that most OSA patients exhibit a broad range of attentional deficits, beyond impaired maintenance of wakefulness, and a specific battery of tests is needed to correctly assess them. Three attentional tests were performed at 9:00, 11:00 and 13:30 h, measuring maintenance of wakefulness, sustained attention and divided attention. Twenty OSA patients (aged 51+/-12 yrs, apnoea/hypopnoea index 45+/-22 h) and 40 control subjects (aged 48.4+/-9.9 yrs) were tested. OSA patients performed significantly less well on the three tests than the controls at the three sessions. This battery of tests demonstrated that 95% of patients had vigilance and/or attentional impairment. Impairment patterns varied between patients. Vigilance is impaired in obstructive sleep apnoea patients over a wide range of attentional processes. Not only is their ability to remain awake in monotonous situations impaired but their ability to maintain attention in more stimulating conditions is also affected. A single test of vigilance is not sufficient and could underestimate impaired vigilance and attention in some patients.

Assessing whole brain perfusion changes in patients with REM sleep behavior disorder

Abstract: Objective: To investigate the regional cerebral perfusion in patients with idiopathic REM behavior disorder (RBD) in order to establish the topography of networks involved. Methods: We performed cerebral blood flow evaluation using 99m Tc-Ethylene Cysteinate Dimer (ECD) SPECT on eight patients with polysomnographically confirmed RBD and nine age-matched controls. Comparisons were made using SPM2. Results: We found increased perfusion in the pons and putamen bilaterally and in the right hippocampus. In addition, we observed a decreased perfusion in frontal (Brodmann area [BA] 4, 6, 10, 43, 44, 47 bilaterally and left BA 9, 46) and temporo-parietal (BA 13, 22, 43 bilaterally and left BA 7, 19, 20, 21, 39, 40, 41, 42) cortices. Conclusion: Perfusional abnormalities in patients with REM behavior disorder were located in the brainstem, striatum, and cortex. These abnormalities are consistent with the anatomic metabolic profile of Parkinson disease.

Which memory processes are affected in patients with obstructive sleep apnea? An evaluation of 3 types of memory.

Abstract: Study Objective; To investigate which memory processes are affected by obstructive sleep apnea (OSA). Design: Three separate memory systems were investigated in patients with OSA and normal subjects. Verbal episodic memory was tested after forced encoding, in order to control the level of attention during item presentation; procedural memory was tested using a simplified version of a standard test with an interfering task; lastly, working memory was examined with validated paradigms based on a theoretical model. Setting; Sleep laboratory and outpatient sleep clinic in a French tertiary-care university hospital. Participants: Ninety-five patients with OSA and 95 control subjects matched for age and level of education. Group 1 (54 patients, 54 controls) underwent an extensive battery of tasks evaluating verbal episodic, procedural, and working memory. Group 2 (16 patients, 16 controls) underwent procedural memory tests only, and group 3 (25 patients, 25 controls) working memory tests only. Interventions: N/A. Measurements and Results: Compared with matched controls, patients with OSA exhibited a retrieval deficit of episodic memory but intact maintenance, recognition, and forgetfulness; decreased overall performance in procedural memory, although pattern learning did occur; and impairment of specific working memory capabilities despite normal short-term memory. No consistent correlation was found between OSA severity and memory deficit. The long duration of the test session did not negatively impact the patients' performance. Conclusions: Memory impairment in OSA is mild and does not affect all memory processes but, rather, specific aspects, underscoring the need for extensive and specific memory testing in clinical and research settings.

Parkinson’s disease: clinical features and diagnosis

Abstract: Objective: Parkinson’s disease (PD) is a progressive neurological disorder characterised by a large number of motor and non-motor features that can impact on function to a variable degree. This review describes the clinical characteristics of PD with emphasis on those features that differentiate the disease from other parkinsonian disorders. Methods: A MedLine search was performed to identify studies that assess the clinical characteristics of PD. Search terms included “Parkinson’s disease”, “diagnosis” and “signs and symptoms”. Results: Because there is no definitive test for the diagnosis of PD, the disease must be diagnosed based on clinical criteria. Rest tremor, bradykinesia, rigidity and loss of postural reflexes are generally considered the cardinal signs of PD. The presence and specific presentation of these features are used to differentiate PD from related parkinsonian disorders. Other clinical features include secondary motor symptoms (eg, hypomimia, dysarthria, dysphagia, sialorrhoea, micrographia, shuffling gait, festination, freezing, dystonia, glabellar reflexes), non-motor symptoms (eg, autonomic dysfunction, cognitive/neurobehavioral abnormalities, sleep disorders and sensory abnormalities such as anosmia, paresthesias and pain). Absence of rest tremor, early occurrence of gait difficulty, postural instability, dementia, hallucinations, and the presence of dysautonomia, ophthalmoparesis, ataxia and other atypical features, coupled with poor or no response to levodopa, suggest diagnoses other than PD. Conclusions: A thorough understanding of the broad spectrum of clinical manifestations of PD is essential to the proper diagnosis of the disease. Genetic mutations or variants, neuroimaging abnormalities and other tests are potential biomarkers that may improve diagnosis and allow the identification of persons at risk.

Control of Sleep and Wakefulness

Abstract: This review summarizes the brain mechanisms controlling sleep and wakefulness. Wakefulness promoting systems cause low-voltage, fast activity in the electroencephalogram (EEG). Multiple interacting neurotransmitter systems in the brain stem, hypothalamus, and basal forebrain converge onto common effector systems in the thalamus and cortex. Sleep results from the inhibition of wake-promoting systems by homeostatic sleep factors such as adenosine and nitric oxide and GABAergic neurons in the preoptic area of the hypothalamus, resulting in large-amplitude, slow EEG oscillations. Local, activity-dependent factors modulate the amplitude and frequency of cortical slow oscillations. Non-rapid-eye-movement (NREM) sleep results in conservation of brain energy and facilitates memory consolidation through the modulation of synaptic weights. Rapid-eye-movement (REM) sleep results from the interaction of brain stem cholinergic, aminergic, and GABAergic neurons which control the activity of glutamatergic reticular formation neurons leading to REM sleep phenomena such as muscle atonia, REMs, dreaming, and cortical activation. Strong activation of limbic regions during REM sleep suggests a role in regulation of emotion. Genetic studies suggest that brain mechanisms controlling waking and NREM sleep are strongly conserved throughout evolution, underscoring their enormous importance for brain function. Sleep disruption interferes with the normal restorative functions of NREM and REM sleep, resulting in disruptions of breathing and cardiovascular function, changes in emotional reactivity, and cognitive impairments in attention, memory, and decision making.

NeuPSIG guidelines on neuropathic pain assessment

Abstract: This is a revision of guidelines, originally published in 2004, for the assessment of patients with neuropathic pain. Neuropathic pain is defined as pain arising as a direct consequence of a lesion or disease affecting the somatosensory system either at peripheral or central level. Screening questionnaires are suitable for identifying potential patients with neuropathic pain, but further validation of them is needed for epidemiological purposes. Clinical examination, including accurate sensory examination, is the basis of neuropathic pain diagnosis. For more accurate sensory profiling, quantitative sensory testing is recommended for selected cases in clinic, including the diagnosis of small fiber neuropathies and for research purposes. Measurement of trigeminal reflexes mediated by A-beta fibers can be used to differentiate symptomatic trigeminal neuralgia from classical trigeminal neuralgia. Measurement of laser-evoked potentials is useful for assessing function of the A-delta fiber pathways in patients with neuropathic pain. Functional brain imaging is not currently useful for individual patients in clinical practice, but is an interesting research tool. Skin biopsy to measure the intraepidermal nerve fiber density should be performed in patients with clinical signs of small fiber dysfunction. The intensity of pain and treatment effect (both in clinic and trials) should be assessed with numerical rating scale or visual analog scale. For future neuropathic pain trials, pain relief scales, patient and clinician global impression of change, the proportion of responders (50% and 30% pain relief), validated neuropathic pain quality measures and assessment of sleep, mood, functional capacity and quality of life are recommended.