Cerebellar hyperperfusion in semantic dementia.

Despite evidence of a cerebellar contribution to language, possible functional changes of the cerebellum in patients with language impairment secondary to cerebral neurodegeneration has not been investigated so far. We examined with resting perfusion single photon emission tomography one patient with semantic dementia and the data were compared with a normal subject database. Region of interest and Statistical Parametric Mapping 2 analysis showed in the patient hypoperfusion of the left temporal and parietal lobe and hyperperfusion in the superior vermis and cerebellar hemispheres (lobules IV, V, and VI). The cerebellum shows increased flow of possible compensatory significance in patients with language disturbance associated to cerebral degenerative changes.

Low brain iron content in idiopathic restless legs syndrome patients detected by phase imaging.

BACKGROUND: The objective of this study was to use phase imaging to evaluate brain iron content in patients with idiopathic restless legs syndrome (RLS). METHODS: Fifteen RLS patients and 15 healthy controls were studied using gradient-echo imaging. Phase analysis was performed on localized brain regions of interest selected on phase maps, sensitive to paramagnetic tissue. Differences between the 2 subject groups were evaluated using ANCOVA including age as a covariate. RESULTS: Significantly higher phase values were present in the RLS patients compared with healthy controls at the level of the substantia nigra, thalamus, putamen, and pallidum, indicating reduced iron content in several regions of the brain of the patients. CONCLUSIONS: We have used MRI phase analysis to study brain iron content in idiopathic RLS in vivo for the first time. Our results support the hypothesis of reduced brain iron content in RLS patients, which may have an important role in the pathophysiology of the disorder.

Abnormal medial thalamic metabolism in patients with idiopathic restless legs syndrome.

Pathophysiology of restless legs syndrome is poorly understood. A role of the thalamus, specifically of its medial portion which is a part of the limbic system, was suggested by functional magnetic resonance imaging and positron emission tomography studies. The aim of this study was to evaluate medial thalamus metabolism and structural integrity in patients with idiopathic restless legs syndrome using a multimodal magnetic resonance approach, including proton magnetic resonance spectroscopy, diffusion tensor imaging, voxel-based morphometry and volumetric and shape analysis. Twenty-three patients and 19 healthy controls were studied in a 1.5 T system. Single voxel proton magnetic resonance spectra were acquired in the medial region of the thalamus. In diffusion tensor examination, mean diffusivity and fractional anisotropy were determined at the level of medial thalamus using regions of interest delineated to outline the same parenchyma studied by spectroscopy. Voxel-based morphometry was performed focusing the analysis on the thalamus. Thalamic volumes were obtained using FMRIB's Integrated Registration and Segmentation Tool software, and shape analysis was performed using the FMRIB Software Library tools. Proton magnetic resonance spectroscopy study disclosed a significantly reduced N-acetylaspartate:creatine ratio and N-acetylaspartate concentrations in the medial thalamus of patients with restless legs syndrome compared with healthy controls (P < 0.01 for both variable). Lower N-acetylaspartate concentrations were significantly associated with a family history of restless legs syndrome (ß = -0.49; P = 0.018). On the contrary, diffusion tensor imaging, voxel-based morphometry and volumetric and shape analysis of the thalami did not show differences between the two groups. Proton magnetic resonance spectroscopic findings in patients with restless legs syndrome indicate an involvement of medial thalamic nuclei of a functional nature; however, the other structural techniques of the same region did not show any changes. These findings support the hypothesis that dysfunction of the limbic system plays a role in the pathophysiology of idiopathic restless legs syndrome.

Catathrenia under sodium oxybate in narcolepsy with cataplexy.

PURPOSE: This study aims to report on catathrenia occurring in narcolepsy with cataplexy (NC) patients under sodium oxybate (SO) treatment. Catathrenia is a parasomnia characterized by groaning and an abnormal respiratory pattern during sleep. METHODS: Fifty-one patients with NC and starting SO therapy underwent a baseline overnight polysomnography (PSG) to detect any sleep-related breathing disorders (SRBD). To avoid risks due to a possible central respiratory control depression by SO, all patients with concomitant obstructive sleep apnea (OSA) were treated with a nasal continuous positive airway pressure (nCPAP) device. After 2 months of treatment with SO, all patients underwent a follow-up overnight PSG to investigate possible newly occurring SRBD. They also underwent a semi-structured clinical interview to monitor other potential SO side effects. RESULTS: At baseline, four out of 51 patients showed simple snoring, and eight, mild to severe OSA. After a titration PSG night, patients with OSA received a nCPAP device. After 2 months of SO treatment, 28 patients (54.9%) showed SO-related side effects, including SRBD in 11 (21.6%). The follow-up PSG showed a respiratory pattern characteristic of catathrenia in seven patients (13.7%) as a newly observed and possibly benign SO side effect, and ruled out a worsening of OSA. CONCLUSIONS: Catathrenia should be considered a possible side effect in NC patients under SO treatment and should be accurately identified to prevent unnecessary SO withdrawal.

Normal body scheme and absent phantom limb experience in amputees while dreaming.

While dreaming amputees often experience a normal body image and the phantom limb may not be present. However, dreaming experiences in amputees have mainly been collected by questionnaires. We analysed the dream reports of amputated patients with phantom limb collected after awakening from REM sleep during overnight videopolysomnography (VPSG). Six amputated patients underwent overnight VPSG study. Patients were awakened during REM sleep and asked to report their dreams. Three patients were able to deliver an account of a dream. In all dreaming recalls, patients reported that the amputated limbs were intact and completely functional and they no longer experienced phantom limb sensations. Phantom limb experiences, that during wake result from a conflict between a pre-existing body scheme and the sensory information on the missing limb, were suppressed during sleep in our patients in favour of the image of an intact body accessed during dream.

Association of restless legs syndrome with nocturnal eating: a case-control study.

We investigated the prevalence of nocturnal eating (sleep-related eating disorder-SRED or night-eating syndrome-NES) in patients with restless legs syndrome (RLS). One hundred RLS patients living in Emilia-Romagna (Northern Italy) and 100 matched controls randomly selected from the general population received two telephone interviews, and were investigated for socio-demographic characteristics, general health status, and presence of nocturnal eating. Additionally, subjects underwent interviews for psychopathological traits [by means of the Eating Disorder Inventory-2 (EDI-2), the Maudsley Obsessive-Compulsive Inventory (MOCI), the Beck Depression Inventory (BDI)], excessive daytime sleepiness (EDS), and subjective sleep quality. Compared with controls, RLS patients had more frequently pathological MOCI scores (24% versus 10%, P = 0.03), used significantly more drugs for concomitant diseases and had more nocturnal sleep impairment and EDS. SRED was more prevalent in RLS patients than controls (SRED: 33% versus 1%, P < 0.001). Medication use and pathological MOCI scores were more prevalent in RLS patients with SRED than among RLS patients without SRED. Use of dopaminergic or hypnotic drugs for RLS was not correlated with the presence of SRED. We demonstrate an association between RLS and SRED. Prospective studies are needed to establish the mechanisms underlying such association and whether it is causal.

Sleep and temperature rhythms in two sisters with P102L Gerstmann-Sträussler-Scheinker (GSS) disease.

BACKGROUND: Sleep disorders are increasingly recognized in the symptomatology of many neurodegenerative diseases. Gerstmann-Sträussler-Scheinker (GSS) disease is a hereditary prion disease featuring cerebellar ataxia, akinetic parkinsonism, pyramidal signs and cognitive decline. METHODS: We performed a polysomnographic study (PSG) of sleep and body core temperature (BcT degrees ) in two sisters with GSS. RESULTS: Our study showed protracted nocturnal awakenings, reduced sleep efficiency and brief daytime naps but also qualitatively preserved slow-wave and REM sleep and substantially normal arousal and periodic limb movements in sleep indices and BcT degrees rhythm. CONCLUSIONS: These findings conflict with those in multiple system atrophy and other prion diseases such as fatal familial insomnia, which enter the differential diagnosis of GSS and are characterized by prominently disrupted sleep-wake and BcT degrees cycles.

Status dissociatus evolving from REM sleep behaviour disorder in multiple system atrophy.

OBJECTIVE: We present two patients, a 52-year-old man and a 56-year-old woman, with rapid eye movement sleep behaviour disorder (RBD) since the age of 50. METHOD: In both the patients RBD was videopolysomnographically documented. RESULTS: Both patients developed, with time, autonomic and motor symptoms consistent with the diagnosis of multiple system atrophy. During the course of the disease RBD episodes diminished in frequency but the patients' sleep became even more abnormal, with nearly continuous motor and verbal abnormal behaviours and ambiguous and rapid oscillations of state-determining polysomnographic variables, now consistent with status dissociatus (SD). CONCLUSION: If SD represents the evolution and most extreme form of RBD it should be investigated longitudinally in neurodegenerative diseases.

Paroxysmal bipedal activity during syncope related to carotid body tumor.

Involuntary patterned motor activity may occur during seizures, especially those of frontal lobe origin, and during transient ischemic attacks. Paroxysmal patterned motor activity in frontal lobe epilepsy has been attributed to direct involvement of mesial frontal regions by the epileptic discharge. Paroxysmal bipedal frenetic activity occurred during an episode of syncope in a patient with a carotid body tumor. The presence of rhythmic motor patterns similar to the epileptic ones also during syncope and cerebral ischemia suggest a phenomenon of release from neocortical inactivation, probably of innate motor behaviors generated by neural networks referred to as central pattern generators (CPGs).

Suggestive evidence for linkage for restless legs syndrome on chromosome 19p13.

Five loci for restless legs syndrome (RLS) on chromosomes 12q, 14q, 9p, 2q, and 20p (RLS1-RLS5) have been mapped in RLS families, with a recessive in the first and autosomal-dominant mode of inheritance in the latter cases. Investigations of further RLS families showed evidence for genetic locus heterogeneity. We have conducted a genome-wide linkage analysis in a large RLS family of Italian origin with 12 affected members in 3 generations using 5,861 single nucleotide polymorphisms (SNP, 6K Illumina). Linkage analysis was performed under an autosomal-dominant model with a complete penetrance, an allele frequency of 0.003 and a phenocopy rate of 0.005. The genome-wide scan resulted in suggestive evidence for linkage on chromosome 19p with maximum multipoint logarithm of the odds score of 2.61 between markers rs754292 and rs273265. The locus was replicated in a family-based association study in a set of 159 trios of European origin. This study provides evidence for a further RLS locus, thus supporting the picture of RLS as a genetically heterogenous complex trait.

Group I nonreciprocal inhibition in primary restless legs syndrome.

Electrophysiological investigations of restless legs syndrome (RLS) have found spinal circuits impinging on motoneurones. We evaluated the H reflex threshold, latency, the Hmax/Mmax ratio, and the short latency autogenic inhibition in 7 patients with RLS and 10 age-matched controls by testing the excitability changes in soleus H reflex Ib interneuron function. A significant reduction in Ib inhibition at 4 (P = 0.043), 5 (P = 0.007), and 6 ms (P = 0.001) of H reflex conditioning interstimulus interval was found in RLS patients. Data support the hypothesis that altered group I nonreciprocal inhibition is implicated in enhancing the spinal circuitry excitability of RLS, and are consistent with the view of an abnormal supraspinal drive to spinal interneurons in RLS.

Daytime sleepiness and neural cardiac modulation in sleep-related breathing disorders.

Sleep-related breathing disorders are common causes of excessive daytime sleepiness, a socially and clinically relevant problem. Mechanisms responsible for daytime sleepiness are still largely unknown. We investigated whether specific alterations in autonomic cardiac modulation during sleep, commonly associated with sleep-related breathing disorders, are related to excessive daytime sleepiness. Fifty-three patients with sleep-related breathing disorders underwent nocturnal polysomnography. Excessive daytime sleepiness was diagnosed as a Multiple Sleep Latency Test response less than or equal to 600 s. We explored the relation of excessive daytime sleepiness, objectively determined, with indices of autonomic cardiac regulation, such as baroreflex sensitivity and heart rate variability, with polysomnographic indices of the severity of sleep-related breathing disorders and with quality of sleep. Patients with excessive daytime sleepiness, when compared with patients without, had significantly lower baroreflex sensitivity and significantly higher low-to-high frequency power ratio of heart rate variability during the different stages of nocturnal sleep. By contrast, no differences were found in indices quantifying the severity of sleep-related breathing disorders or sleep quality. We demonstrated that excessive daytime sleepiness is accompanied by a deranged cardiac autonomic control at night, the latter probably reflecting autonomic arousals not detectable in the EEG. As abnormal autonomic regulation is also known to be associated with increased cardiovascular risk, a possible relation between excessive daytime sleepiness and cardiovascular events in patients with sleep-related breathing disorders deserves to be investigated in future studies.

Sympathetic and cardiovascular activity during cataplexy in narcolepsy.

Autonomic nervous system activity changes have been described during cataplexy as playing a role in triggering it. To confirm these previous findings, we investigated the time course of sympathetic and cardiovascular activities during cataplexy. We made for the first time microneurographic recordings of 10 cataplectic episodes in three patients with hypocretin-deficient narcolepsy. During microneurography, muscle sympathetic nerve activity (MSNA) was recorded simultaneously with heart rate (HR), respiratory movements, arterial finger blood pressure (BP), electroencephalography, electro-oculogram and superficial electromyogram. Results showed no significant autonomic changes before the onset of the cataplectic episodes. Cataplexy was associated with a significant increase in MSNA and BP compared with baseline, whereas HR was markedly decreased. An irregular breathing pattern mainly characterized by apnea typically occurred during the attacks. In conclusion, our findings did not show significant changes in autonomic activity prior to cataplexy onset, ruling out a triggering role of the autonomic system. However, cataplexy was associated with co-activation of sympathetic and parasympathetic autonomic systems, a pattern reminiscent of that reported during the vigilance reaction in animals.

Proton magnetic resonance spectroscopy study of brain metabolism in obstructive sleep apnoea syndrome before and after continuous positive airway pressure treatment.

STUDY OBJECTIVES: Obstructive sleep apnoea syndrome (OSAS) causes sleep related oxygen desaturation, excessive daytime sleepiness (EDS), and cognitive impairment. The role of hypoxic brain damage, sleep fragmentation, and the associated comorbidities (hypertension, vascular disorders) in the pathogenesis of cognitive deficits remains controversial. The aim of this study was to evaluate the cerebral metabolism of OSAS patients in vivo before and after CPAP treatment. DESIGN AND PATIENTS: Fourteen OSAS patients without cardiovascular or cerebrovascular impairment underwent the same protocol before and after 6 months of CPAP including: overnight videopolysomnography (VPSG), Multiple Sleep Latency Test (MSLT), and within the next 2 days neuropsychological and 1H-MRS evaluations. Single voxel 1H-MRS was performed in the parietal-occipital cortex, and absolute concentrations of N-acetyl-aspartate (NAA), creatine, and choline were measured, acquiring spectra at multiple echo-times and using water as internal standard. Ten matched controls were also studied. RESULTS: OSAS patients had a mean RDI of 58/hr, a mean arousal index of 57/hr, and a mean nadir SpO2 of 71%. Before CPAP, all patients showed a normal global cognitive functioning, with only a small number of pathological tasks in working memory and attention tests in a minority of patients. CPAP therapy was effective in resolving sleep apnoea and normalizing sleep structure, and improving EDS and neuropsychological alterations. Before CPAP treatment cortical [NAA] in OSAS (11.86 mM +/- 0.80, mean +/- SD) was significantly lower than in controls (12.85 +/- 0.93; P = 0.01) and positively correlated with minimum SpO2 during sleep (r = 0.69; P = 0.006) and MSLT scores (r = 0.62; P = 0.01). Cortical [NAA] reduction persisted after therapy (11.94 +/- 1.33; P = 0.87 versus pre-CPAP). CONCLUSIONS: OSAS patients have cortical metabolic changes consistent with neuronal loss even in the absence of vascular comorbidities. Metabolic changes persisted after CPAP in the absence of EDS, nocturnal arousals, and major cognitive deficits, likely related to hypoxic damage prior to CPAP treatment.

Movement disorders in sleep: guidelines for differentiating epileptic from non-epileptic motor phenomena arising from sleep.

Seizures, namely in certain epileptic conditions, may be precipitated by sleep. Nocturnal frontal lobe epilepsy seizures, characterized by bizarre motor behaviour and autonomic activation, appear almost exclusively during sleep. The differential diagnosis between this condition and sleep-related non-epileptic paroxysmal motor phenomena, in particular the parasomnias, is arduous. Moreover, accepted criteria for the diagnosis of nocturnal frontal lobe seizures are lacking and even ictal scalp EEG recording could fail to disclose paroxysmal abnormalities. The clinical and polygraphic features of the different types of seizures in nocturnal frontal lobe epilepsy and of the more common non-epileptic paroxysmal events during sleep are described. The main differentiating features characterizing nocturnal frontal seizures are: onset at any age, several attacks per night at any time during the night, brief duration (s) with stereotyped motor pattern. As video-polysomnographic recordings of the attack, the gold-standard for diagnosis, are expensive and not readily available everywhere, home-made video recordings may be helpful. Further investigations on pathophysiology, genetics and epidemiology are needed to clarify the relationship between epileptic and non-epileptic sleep related paroxysmal phenomena.

Pontine hyperperfusion in sporadic hyperekplexia.

OBJECTIVE: To explore with neuroimaging techniques the anatomical and functional correlates of sporadic hyperekplexia. METHODS: Two elderly women with sporadic hyperekplexia underwent neurophysiological assessment, MRI of the brain and proton magnetic resonance spectroscopy (1H-MRS) of the brainstem and frontal lobes. Regional cerebral blood flow was investigated with single photon emission tomography (SPECT) during evoked startles and at rest. RESULTS: Both patients showed excessively large and non-habituating startle responses. In both patients, MRI showed impingement of the brainstem by the vertebrobasilar artery, lack of frontal or brainstem abnormalities on 1H-MRS and hyperperfusion in the dorsal pons and cingulate cortex, and superior frontal gyrus at SPECT during evoked startles. CONCLUSIONS: In our patients with hyperekplexia, the vertebrobasilar arteries were found to impinge on the brainstem. Neurophysiological findings and neurofunctional imaging of evoked startles indicated a pontine origin of the movement disorder modulated by activation in cortical, especially frontal, areas. The neurofunctional correlates of evoked startles in human sporadic hyperekplexia are similar to those observed for the startle circuit in animals.

Impaired cortical and autonomic arousal during sleep in multiple system atrophy.

OBJECTIVE: Periodic limb movements during sleep (PLMS) in Restless Legs Syndrome (RLS) are associated with arousals and stereotyped EEG and heart rate (HR) changes. We investigated PLMS-related EEG and HR variations in multiple system atrophy (MSA) in order to detect possible abnormalities in cortical and autonomic arousal responses. METHODS: Ten patients with MSA were contrasted against ten patients with primary RLS. Cortical (EEG) and autonomic (HR) variations associated with PLMS during NREM sleep were analysed by means of Fast Fourier Transform and HR analysis. In addition, we analysed the cyclic alternating pattern (CAP) during sleep, CAP representing a measure of the spontaneous arousal oscillations during NREM sleep. RESULTS: PLMS in RLS were associated with tachycardia and spectral EEG variations, beginning about 2s before the onset of PLMS, and peaking 1-4s after. The HR and spectral EEG variations were strikingly reduced or absent in MSA. MSA patients also had significantly lower CAP rate compared to RLS patients. CONCLUSIONS: Blunted HR and EEG spectral changes adjacent to PLMS indicated impaired cortical and autonomic arousal responses during sleep in MSA patients. SIGNIFICANCE: PLMS, when present, may represent a useful means to study the arousal responses during sleep.

Nocturnal eating: sleep-related eating disorder or night eating syndrome? A videopolysomnographic study.

STUDY OBJECTIVES: To describe the clinical and videopolysomnographic characteristics of nocturnal eating episodes in sleep-related eating disorder. DESIGN: Descriptive study of outpatients prospectively enrolled in 2 sleep centers. SETTING: Videopolysomnographic recordings done in the sleep laboratory. PATIENTS: Thirty-five consecutive drug-free patients with nocturnal eating. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Clinical interviews disclosed abnormal compulsory nocturnal eating episodes in all patients associated with a clinical report of sleepwalking (in 1), somniloquy (in 5), restless legs syndrome (in 8), and periodic limb movements during sleep (in 4). Videopolysomnography documented 45 episodes of nocturnal eating in 26 patients. Eating always occurred after complete awakenings from non-rapid eye movement sleep and only in 1 patient from REM sleep and was characterized by electroencephalographic alpha activity with no dissociated features of state-dependent sleep variables. Patients interviewed during the eating episodes were fully conscious and remembered the events the next day. Pathological periodic limb movements during sleep index was recorded in 22 and restless legs syndrome dyskinesias in 5 patients. Recurring chewing and swallowing movements during sleep were a feature in 29 patients, associated in about half of the events with electroencephalographic arousals. CONCLUSIONS: In our patients, eating episodes occurred with normal consciousness and recall. Chewing or swallowing movements during sleep occurred frequently, resembling rhythmic masticatory-muscle activity in bruxism patients. The presence of periodic limb movements during sleep and chewing activity, the reported efficacy of dopaminergic medications, and the compulsory food-seeking behavior all argue for a dopaminergic dysfunction underlying the pathogenesis of sleep-related eating disorder.

Restless legs syndrome and periodic limb movements.

The history, clinical aspects, and treatment of restless legs syndrome (RLS), a heterogeneous distressing sensorimotor disorder, and periodic limb movements (PLMs) that are the typical motor accompaniment of the syndrome, are described. A positive family history, a positive response to dopaminergic treatment, and the presence of PLM while awake or asleep are supportive criteria for the diagnosis of the disorder. RLS and PLM occur more frequently at the beginning of night and exponentially decline across sleep cycles, suggesting circadian influences. Altered circadian rhythmicity in dopamine metabolism and enhanced circadian variations in dopaminergic functions have been reported in the disorder. Dysfunction or atrophy of A11 cells from the diencephalic-spinal dopamine A11 system has been suggested to explain the efficacy of dopaminergic drugs in relieving RLS symptoms and the circadian rhythmicity of RLS. Studies support the hypothesis that the A11 dopaminergic neurons and spinal pathways may be more involved in the pathophysiology of RLS than the nigrostriatal system. Neurophysiological evidence indicates that the involuntary movements in RLS may be of spinal or propriospinal origin. Despite these findings, however, the pathogenic mechanisms underlying the peculiar sensory and motor manifestations of RLS remain unexplained. Among the current treatment options offered for the treatment of RLS, dopaminergic agents have provided the best evidence for efficacy in symptom relief.