[Cognitive event-related brain potentials (P300) in patients with normal pressure hydrocephalus. Results of a prospective study]

OBJECTIVE

To determine the response to cognitive event-related potentials (P300) in patients with normal-pressure hydrocephalus (NPH) and their relationship with clinical and cognitive status before and after shunt surgery.

METHODS

We performed a prospective study in a series of 26 patients with NPH who underwent clinical and cognitive assessment before surgery and 6 months afterwards. Visual P300 potentials obtained before and after treatment were also compared with those obtained in 18 healthy volunteers.

RESULTS

Before shunting, the P300 wave was detected in 11 (42.3%) NPH patients, compared with the 18 (100%) volunteers. Six months after shunting, the P300 wave was found in 20 (76.9%) NPH patients. P300 latency was significantly longer in NPH patients than in the control group before surgery, but not at 6 months after surgery. No significant differences in neuropsychological studies or in the level of dependence for daily life activities were found between the subgroups of NPH patients with and without pre-surgical P300 waves, or between changes in P300 parameters and clinical and cognitive changes.

CONCLUSIONS

The P300 wave was delayed or undetectable in a substantial percentage of patients with NPH before surgery. These alterations can be reversed by shunting. P300 analysis and neuropsychological tests could be complementary measures to evaluate functional status in patients with NPH.

Self-reported sleepiness while driving as a risk factor for traffic accidents in patients with obstructive sleep apnoea syndrome and in non-apnoeic snorers

The obstructive sleep apnoea syndrome (OSAS) is a condition causing daytime sleepiness and has been related to an increased risk for traffic accidents. However, the evidence linking severity of OSAS to a higher rate of automobile crashes is based on limited data. The aims of this study were to study the traffic accident rate in the last 5 years in patients referred to our sleep clinic because of clinical suspicion of OSAS and to analyse variables related to an increased risk for traffic accidents. A series of 189 consecutive patients with a driving license referred for a sleep study because of OSAS clinical suspicion and a control group (CG) of 40 hospital staff workers who denied snoring, matched for age and sex with the study population, were studied. Patients underwent a full-night polysomnography and both patients and the CG completed a self-answered questionnaire. One hundred and twenty-two patients were diagnosed as OSAS and 67 patients as non-apnoeic snorers (NAS). The self-reported number of accidents was significantly higher in OSAS patients compared with CG. The self-reported number of times off the road was significantly higher in OSAS patients compared with NAS and with CG. Variables associated with an increased risk for traffic accidents were self-reported sleepiness while driving (OR 5, 95%CI 2.3-10.9), having quit driving because of sleepiness (OR 3, 95%CI 1.1-8.6) and being currently working (OR 2.8, 95%CI 1.1-7.7). We conclude that self-reported sleepiness while driving is associated with an increased risk for traffic accidents in OSAS patients and in NAS. We suggest that this symptom can be used to alert patients and to give priority in the sleep clinic for study and treatment.

Cognitive changes after cerebrospinal fluid shunting in young adults with spina bifida and assumed arrested hydrocephalus

OBJECTIVES

To establish whether surgery can improve the neuropsychological functioning of young adult patients with spina bifida and apparent clinically arrested hydrocephalus showing abnormal intracranial pressure.

METHODS

Twenty three young adults with spina bifida and assumed arrested hydrocephalus (diagnosed as active or compensated by continuous intracranial pressure monitoring) underwent surgery. All patients received neuropsychological examination before surgery and 6 months later. Neuropsychological assessment included tests of verbal and visual memory, visuospatial functions, speed of mental processing, and frontal lobe functions.

RESULTS

Shunt placement in this subgroup of patients improves neuropsychological functioning, especially in verbal and visual memory and attention and cognitive flexibility.

CONCLUSIONS

Young adults with spina bifida and suspected non-functioning shunt or non-shunted ventriculomegaly should be carefully monitored to identify those who could benefit from shunting.

[Modifications in sleep with aging]

INTRODUCTION

Literature reviewed shows that aging sleep is characterized by a decrease in the ability to stay asleep, resulting in a more fragmented sleep and a decrease in daytime alertness. It exists also an advance of phase, a shortening of wake-sleep period and a desincronitation of circadian rhythms.

DEVELOPMENT AND CONCLUSIONS

Changes in circadian rhythms are associated with a decrease of sleep quality. There are a marked reduction of deep slow wave sleep, sleep spindles are less frequent, less ample and shorter. REM sleep appearance is almost uniform during night and REMs density does not increase toward the end of the sleep period. The sleep-wake circadian rhythm is advanced, the temperature rhythm is advanced and the rhythm of cortisol secretion is also advanced. The GH and melatonin peaks of secretion are decreased in elderly.

[Diagnosis and treatment of the phobia due to treatment with air using nasal continuous pressure]

INTRODUCTION

The obstructive sleep apnoea syndrome (OSAS) is characterized by destructured sleep due to repeated episodes of obstruction of the superior respiratory tract during sleep. Treatment by nasal continuous positive airway pressure (n-CPAP) using air is one of the most common forms of treatment of OSAS, although some patients cannot tolerate it. One of the causes of intolerance of n-CPAP is the phobic reaction of some patients.

OBJECTIVE

The objective of this study is to show that phobia is one of the causes of n-CPAP not being accepted by OSAS patients and demonstrates the efficacy of treatment by exposure in cases of phobic fear of mask. Patients and methods. We studied six patients with phobic intolerance of CPAP and established the diagnosis of phobia according to the criteria of DSM-IV. Subsequently, they were treated by real-life exposure, one of the behavior techniques most often used for phobic disorders, and consisting of exposure to the feared object under conditions in which escape or avoidance is impossible.

CONCLUSION

Following the diagnosis of phobia of the CPAP mask, it was seen that treatment involving real-life exposure was effective.

[Accidents prevalence in a group of patients with the narcolepsy- cataplexy syndrome]

INTRODUCTION

Recent studies have shown statistically that the proportion of accidents at work, at home and on the roads is greater in narcoleptic patients than in the general population.

OBJECTIVE

The object of this study is to show the high prevalence of the risk of accidents in patients diagnosed as having the narcolepsy-cataplexy syndrome.

PATIENTS AND METHODS

We studied a group of 35 patients of both sexes, diagnosed in the Sleep Pathology Unit of our hospital between 1994 and 1998 as having the narcolepsy-cataplexy syndrome. They filled out a questionnaire to find the prevalence of accidents. The data obtained regarding the type and number of accidents, their causes, gravity, legal and economic consequences were compared with those obtained in a group of 25 healthy subjects using the chi squared test.

RESULTS

The results showed a higher risk of accidents in narcoleptic as compared with normal persons, with a statistically significant difference between the two groups.

CONCLUSIONS

This study has shown the greater risk of accidents in these patients and the need for diagnosis as soon as possible so as to establish suitable treatment and thus improve their own personal safety and that of those around them.

Nocturnal sleep structure and temperature slope in MPTP treated monkeys

The nocturnal sleep of three 1-Methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine (MPTP) treated monkeys (one non-motor disabled and two severely motor disabled), while held in a primate chair was registered using a reversible system for head fixation and chronic recordings. Two electroencephalogram (EEG) channels, one electrooculogram (EOG) and one electromyogram (EMG) channel were monitored constantly and tape recorded during eight nights for posterior analyses. Subcutaneous temperature was registered each minute using a radio telemetry system. An analysis of sleep patterns and temperature parameters revealed lighter sleep, decreased amounts of slow wave and rapid eye movement (REM) sleep and lower temperature values in the two motor disabled MPTP-treated monkeys than in the non-motor disabled monkey. The temperature linear slope was negative in the case of one disabled monkey for just one night. Although the motor disability of the two monkeys was similar, their sleep organization patterns and temperatures slopes differed. The present study confirmed the differential vulnerability of the nigrostriatal system of monkeys to MPTP, suggesting that if a high cumulative dose was needed to reach stable motor alterations, the cumulative dose-effect of the toxin independent of the nigrostriatal system might be responsible for non-motor symptoms that also appear in Parkinson's disease besides the classic tetrad.

Nasal continuous positive airway pressure with supplemental oxygen in coexistent sleep apnoea-hypopnoea syndrome and severe chronic obstructive pulmonary disease

The objective of our study was to assess the application of nasal continuous positive airway pressure (nCPAP) with supplemental oxygen for correction of upper airway obstructive episodes and hypoxaemia during sleep in stable patients with sleep apnoea-hypopnoea syndrome (SAHS) and severe chronic obstructive pulmonary disease (COPD). Ten male patients with symptomatic SAHS and severe COPD (forced expiratory volume in one second < 50% of predicted) were studied for three consecutive nights. Diagnostic polysomnography was performed the first night and repeated with increasing nCPAP levels, with and without supplemental oxygen on the second and third nights, respectively. Diagnostic polysomnography showed: mean (SD) apnoea-hypopnoea index 41 (22) events.h-1; mean arterial oxygen saturation (Sa,O2) was 86 (2)% and mean desaturation nadir was 81 (4)% during non-rapid eye movement (nREM) sleep and 80 (7)% and 73 (9)%, respectively during REM sleep. The application of nCPAP during the second night corrected apnoeas and hypopnoeas, but mean Sa,O2 remained < 90% in all patients. With the addition of oxygen at a flow of 1.5 L.min-1 at suboptimal nCPAP levels, we observed an increase in apnoea frequency, persistence of apnoeas at nCPAP levels which eliminated them when no supplemental oxygen was administered, and longer duration of apnoeas and hypopnoeas. However, when the effective nCPAP level of the second night was reached with supplemental oxygen during the third night, its efficacy in eliminating apnoeas and hypopnoeas was maintained and, furthermore, all patients presented Sa,O2 > 90%, with no greater hypercapnia cardiac arrhythmias. We conclude that nasal continuous positive airway pressure with supplemental oxygen constitutes a practical therapeutic alternative for hypoxic patients with sleep apnoea-hypopnoea syndrome and chronic obstructive pulmonary disease.

Absence of REM sleep and altered non-REM sleep caused by a haematoma in the pontine tegmentum

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Brain mapping analysis in patients with hepatic encephalopathy

Topographical analysis of cerebral electrical activity was performed in 44 patients with hepatic encephalopathy. These patients were classified in 5 groups according to clinical criteria. Eight healthy subjects were used as a control group. All were studied in an awake, eyes closed, condition and some [Control Group (CG), Group 0 (G0), Group 1 (G1) and Group 2 (G2)] also in an awake, eyes open, condition. The awake, eyes closed, maps showed marked differences in the power spectral density (PSD) of the different bands, when comparing normal subjects with patients with several degrees of hepatic encephalopathy. These differences were related to the degree of clinical involvement, mainly in the alpha and delta PSD bands. The combination of a decreased alpha PSD, increased delta PSD, and decreased mean dominant frequency (MDF) allowed a clear discrimination between the different clinical groups. The differences observed between awake, eyes closed, and awake, eyes open, conditions were especially helpful to discriminate between CG subjects and G0, G1 and G2 patients.