Daytime sleep in Parkinson's disease measured by episodes of immobility.

Excessive daytime sleepiness (EDS) is common in Parkinson's Disease (PD). Actigraphy uses periods of immobility as surrogate markers of nighttime sleep but there are no examples of its use in assessing EDS of PD. A commercial wrist worn system for measuring bradykinesia and dyskinesia also detects 2 min periods of immobility, which have a 85.2% concordance with the detection of sleep by ambulatory daytime polysomnography, (p < 0.0001 Chi Squared). High Epworth Sleepiness Scores (ESS) were associated with a proportion of time immobile (PTI) (p = 0.01 Mann-Whitney U). The median PTI between 0900 and 1800 h w in 30 age matched control subjects was 2%, representing 10 min and PTI at or above the 75th percentile (5% or 27 min) was taken as a high level. PD patients had higher PTI (median 4.8%) than controls (p < 0.0001, Mann-Whitney U). PD subjects with a high PTI had more bradykinesia, less dyskinesia and higher PDQ39 scores than those with low PTI. There was no relationship between PTI and dose or type of PD medications. However, in 53% of subjects, PTI increased in the 30-60 min after levodopa confirming that in some subjects levodopa results in increased sleepiness. In summary, immobility is a surrogate marker of daytime sleep in PD, confirmed by correlation with PSG and ESS. PD subjects measured this way are more likely to be sleepy and sleepy PD subjects are more likely to be bradykinetic and have a higher PDQ39. Levodopa leads to an increase in sleepiness in more than half of subjects post dosing.

Can actigraphy measure sleep fragmentation in children?

OBJECTIVE: The gold standard assessment for sleep quality is polysomnography (PSG). However, actigraphy has gained popularity as an ambulatory monitor. We aimed to assess the value of actigraphy in measuring sleep fragmentation in children. METHODS: 130 children aged 2-18 years referred for assessment for sleep disordered breathing (SDB) were recruited. The arousal index (AI) scored from PSG was compared to the actigraphic fragmentation index (FI) and number of wake bouts/h. RESULTS: The ability of actigraphic measures to correctly classify a child as having an AI>10 events/h rated as fair for the FI and poor for wake bouts/h (area under the receiver operator characteristic curve, 0.73 and 0.67, respectively). CONCLUSION: Actigraphy provides only a fair indication of the level of arousal from sleep in children. While the limitations of actigraphy prevent it from being a diagnostic tool for SDB, it still has a role in evaluating sleep/wake schedules in children.

Adaptive servo-ventilation and deadspace: effects on central sleep apnoea.

Central Sleep Apnoea (CSA) occurs commonly in heart failure. Adaptive servo-ventilation (ASV) and deadspace (DS) have been shown in research settings to reverse CSA. The likely mechanism for this is the increase of PaCO(2) above the apnoeic threshold. However the role of increasing FiCO(2) on arousability remains unclear. To compare the effects of ASV and DS on sleep and breathing, in particular effects on Arousal Index (ArI), ten male patients with heart failure and CSA were studied during three nights with polysomnography plus measurements of PetCO(2). The order of the interventions control (C), ASV and DS was randomized. ASV and DS caused similar reductions in apnoea-hypopnoea index [(C) 30.0 +/- 6.6, (ASV) 14.0 +/- 3.8, (DS) 15.9 +/- 4.7 e h(-1); both P < 0.05]. However, DS was associated with decreased total sleep time compared with C (P < 0.02) and increased spontaneous ArI compared to C and ASV (both P < 0.01). Only DS was associated with increased DeltaPetCO(2) from resting wakefulness to eupnic sleep [(C) 2.1 +/- 0.9, (ASV) 1.3 +/- 1.0, (DS) 5.6 +/- 0.5 mmHg; P = 0.01]. ASV and DS both stabilized ventilation however DS application also increased sleep fragmentation with negative impacts on sleep architecture. We speculate that this effect is likely to be mediated by increased PetCO(2) and respiratory effort associated with DS application.

Symptom burden of sleep-disordered breathing in mild-to-moderate congestive heart failure patients.

The symptom burden resulting from sleep-disordered breathing (SDB) in patients with mild-to-moderate congestive heart failure (CHF) is unclear. The current authors monitored 24-h activity levels and compared subjective and objective measures of daytime sleepiness in 39 CHF patients, New York Heart Association class 2-3, on optimal medication. A total of 22 patients were classified as SDB (apnoea/hypopnoea index (AHI) median (range) 22.3 (16.6-100) events.h-1), and 17 as no SDB (NoSDB; AHI 3.7 (0-12.3) events.h-1). SDB was defined as AHI>or=15 events.h-1. Patients were assessed by 24-h activity monitoring (actigraphy) for a period of up to 14 days, a single objective sleepiness test (Oxford Sleep Resistance test) and Epworth Sleepiness Scale. The duration of daytime activity was significantly shorter in the SDB group compared with the NoSDB group. The SDB group also had increased time in bed and poorer sleep quality, as shown by the fragmentation index. Objectively the SDB group when compared with the NoSDB group were significantly sleepier, subjectively the groups did not differ. The amount of napping was similar for both groups. Despite the lack of subjective symptoms of daytime sleepiness, congestive heart failure patients with sleep-disordered breathing were objectively sleepier during the day and had reduced daytime activity with longer periods in bed and poorer sleep quality when compared with those without sleep-disordered breathing.

The interaction between respiratory and autonomic function during sleep-related changes in pharyngeal airway patency.

Sleep-related changes in pharyngeal function result in an increased resistance to airflow and in some people complete pharyngeal occlusion. Clinically, pharyngeal occlusion causes obstructive sleep apnoea syndrome (OSA). This is a prevalent disorder, which is an independent risk factor for the development of systemic hypertension. Several mechanisms contribute to the sleep-related changes in pharyngeal function in both health and disease, including a reduction in respiratory-related muscle activation, and an increase in latency of the pharyngeal reflex to negative intralumenal pressure. Arousal from sleep causes increases in ventilation and autonomic cardiovascular function that far exceed physiological requirements--the so-called 'waking reflex'. In patients with OSA the waking reflex is augmented either by hypoxemia, hypercapnia, or large swings in intrathoracic pressure. How these factors interact to cause the acute surges in heart rate and systemic blood pressure that occur at the termination of an apnoea will be reviewed, together with the longer term consequences of pharyngeal occlusion during sleep.

Non-deflation of Foley catheter balloon: use of transrectal ultrasound.

The problem of failed balloon deflation on removal of a Foley catheter is frequently observed. The use is reported of transrectal ultrasound with a small gauge biopsy needle to enable balloon deflation after the failure of less invasive techniques.

Some dynamic factors in compressive deformity of the cervical spinal cord.

An investigation into the relative elastic and non-elastic components of compressive deformity of the cervical spinal cord has been made. Sixteen patients were examined by computed myelography with the neck flexed and extended, and one fresh specimen of a human spinal cord was studied under reversible transverse compression with the specimen in a stretched and shortened state. In conditions of transverse compression cord tissue undergoes an alteration in viscoelastic properties, manifesting itself as reduced expansion of the compressed segment as the cord shortens, which in some cases is independent of whether the agent is seen to actually contact the cord. The presence of degenerative changes in cord substance probably accentuates this alteration in mechanical properties.