The effect of weight loss on OSA severity and position dependence in the bariatric population.

BACKGROUND: The aims of this study were to determine the prevalence of positional obstructive sleep apnea (POSA) in patients undergoing bariatric surgery and to evaluate the effect of weight loss brought about by bariatric surgery on POSA. Furthermore, the authors investigated whether body mass index (BMI), neck circumference, apnea-hypopnea index (AHI), and age are predictors for POSA. METHOD: A retrospective cohort study was conducted with data collected from patients who were screened for OSA pre-bariatric surgery and completed a follow-up polysomnography post bariatric surgery from August 2008 to November 2012. Descriptive statistics were used to characterize the prevalence of POSA patients, and the Mann-Whitney and Wilcoxon signed-rank tests were used to examine differences between the POSA and non-POSA groups. A logistic regression model was used to determine predictors for POSA. RESULTS: Thirty-four percent of patients had POSA, which is significantly lower (p<0.001) than in the general population. BMI, neck circumference, and AHI were significantly lower in POSA patients. AHI was the only significant independent predictor for POSA. Of the 91 patients analyzed following bariatric surgery, 35.2% (n=32) no longer had OSA. CONCLUSION: The prevalence of POSA in patients undergoing bariatric surgery is significantly lower than the prevalence noted in the general population. A low AHI was shown to be the only significant independent predictor for the presence of POSA.

The sleep position trainer: a new treatment for positional obstructive sleep apnoea.

BACKGROUND: Positional obstructive sleep apnoea (POSA), defined as a supine apnoea-hypopnoea index (AHI) twice or more as compared to the AHI in the other positions, occurs in 56 % of obstructive sleep apnoea patients. Positional therapy (PT) is one of several available treatment options for these patients. So far, PT has been hampered by compliance problems, mainly because of the usage of bulky masses placed in the back. In this article, we present a novel device for treating POSA patients. METHODS: Patients older than 18 years with mild to moderate POSA slept with the Sleep Position Trainer (SPT), strapped to the chest, for a period of 29 ± 2 nights. SPT measures the body position and vibrates when the patient lies in supine position. RESULTS: Thirty-six patients were included; 31 patients (mean age, 48.1 ± 11.0 years; mean body mass index, 27.0 ± 3.7 kg/m(2)) completed the study protocol. The median percentage of supine sleeping time decreased from 49.9 % [20.4-77.3 %] to 0.0 % [range, 0.0-48.7 %] (p < 0.001). The median AHI decreased from 16.4 [6.6-29.9] to 5.2 [0.5-46.5] (p < 0.001). Fifteen patients developed an overall AHI below five. Sleep efficiency did not change significantly. Epworth Sleepiness Scale decreased significantly. Functional Outcomes of Sleep Questionnaire increased significantly. Compliance was found to be 92.7 % [62.0-100.0 %]. CONCLUSIONS: The Sleep Position Trainer applied for 1 month is a highly successful and well-tolerated treatment for POSA patients, which diminishes subjective sleepiness and improves sleep-related quality of life without negatively affecting sleep efficiency. Further research, especially on long-term effectiveness, is ongoing.

Hypothermia after CPR prolongs conduction times of somatosensory evoked potentials.

BACKGROUND: To investigate the effect of mild hypothermia on conduction times and amplitudes of median nerve somatosensory evoked potentials (SEP) in patients after cardiopulmonary resuscitation (CPR). METHODS: Patients treated with hypothermia after CPR who underwent SEP recording during hypothermia and after rewarming were selected from a prospectively collected database. Latencies and amplitudes of N9 (peripheral conduction time, PCT), N13, and N20 were measured. The central conduction time (CCT) was defined as peak-peak latency N13-N20. Recordings of 25 patients were assessed by a second observer to determine the intraclass correlation coefficient (ICC). RESULTS: A total of 115 patients were included. The mean body temperature at SEP during hypothermia was 33.1 °C (SD 0.8) and after rewarming 37.1 °C (SD 0.8). Mean latencies of N9, N13, and N20 and mean CCT were longer during hypothermia. There were no consistent differences in amplitudes. There was an almost perfect ICC for assessment of latencies and amplitudes. CONCLUSIONS: This study showed that PCT and CCT of median nerve SEP were prolonged during treatment with hypothermia after CPR compared with after rewarming. Amplitudes did not differ consistently.

Evaluation of a new simple treatment for positional sleep apnoea patients.

Obstructive sleep apnoea syndrome is a common clinical problem. Positional sleep apnoea syndrome, defined as having a supine apnoea-hypopnoea index of twice or more compared to the apnoea-hypopnoea index in the other positions, occurs in 56% of obstructive sleep apnoea patients. A limited number of studies focus on decreasing the severity of sleep apnoea by influencing sleep position. In these studies an object was strapped to the back (tennis balls, squash balls, special vests), preventing patients from sleeping in the supine position. Frequently, this was not successful due to arousals while turning from one lateral position to the other, thereby disturbing sleep architecture and sleep quality. We developed a new neck-worn device which influences sleep position by offering a vibration when in supine position, without significantly reducing total sleep time. Thirty patients with positional sleep apnoea were included in this study. No side effects were reported. The mean apnoea-hypopnoea index dropped from 27.7 ± 2.4 to 12.8 ± 2.2. Seven patients developed an overall apnoea-hypopnoea index below 5 when using the device in ON modus. We expect that positional therapy with such a device can be applied as a single treatment in many patients with mild to moderate position-dependent obstructive sleep apnoea, while in patients with a more severe obstructive sleep apnoea such a device could be used in combination with other treatment modalities.

Partial clinical response to 2 weeks of 2 Hz repetitive transcranial magnetic stimulation to the right parietal cortex in depression.

The aim of this treatment study was to evaluate the therapeutic effects of repetitive transcranial magnetic stimulation (rTMS) over the right parietal cortex in depression. In a double-blind, sham-controlled design ten consecutive sessions of 2 Hz rTMS (inter-pulse interval 0.5 s) at 90% motor threshold to the right parietal cortex (2400 pulses per session) were applied to 34 patients with the primary diagnosis of DSM-IV depression and a score of > or =15 on the 17-item Hamilton Rating Scale for Depression (HAMD). The primary outcome measures were the percentage change from baseline on the 17-item HAMD scores after ten sessions, and the percentage of clinical (defined as > or =50% reduction in HAMD score) and partial clinical (defined as > or =30% reduction in HAMD score) responders. Reduction of HAMD scores in the real rTMS treatment (mean real+/-S.D., -19.9+/-32.5%) was not statistically different from the sham rTMS treatment (mean sham+/-S.D., -5.6+/-28.4%), and the number of clinical responders did not differ between treatments. However, a significant greater number of partial clinical responders were observed in the real (43.8%) compared to the sham rTMS treatment (6.3%). This study provides the first evidence showing that 2 Hz rTMS over the right parietal cortex may have antidepressant properties, and warrants further research.

Acute cyanide poisoning complicated by lactic acidosis and pulmonary edema.

Massive cyanide poisoning occurred in a 21-year-old man who had ingested 600 mg of potassium cyanide. The clinical course was marked by acute pulmonary edema and lactic acidosis. Because the poison was unidentified until nine hours after ingestion, the patient received only supported treatment which included diuresis, oxygen, bicarbonate, and assisted ventilation. A review of the literature shows that many case reports are poorly documented and do not provide a firm basis for evaluating therapy. To our knowledge, only four patients, including ours, have had blood levels of cyanide measured. In the absence of a suitable history, diagnosis of cyanide poisoning is difficult. A simple chemical test which can be performed on gastric aspirate is available. Hydroxocobalamin may be used as a nontoxic specific antidote. Nonspecific supportive therapy is of great importance.

A 3-month, follow-up, randomized, placebo-controlled study of repetitive transcranial magnetic stimulation in depression.

BACKGROUND/OBJECTIVE: There is evidence for an antidepressant effect of repetitive transcranial magnetic stimulation (rTMS), but little is known about posttreatment course. Therefore, we conducted a placebo-controlled, double-blind study in depressed patients in order to investigate the effect of rTMS on depression over 12 weeks after completion of the 2-week stimulation period. METHOD: 55 patients with a moderate or severe DSM-IV major depressive episode were randomly assigned to rTMS or sham treatment. rTMS was given daily for 10 days over the left dorsolateral prefrontal cortex with the following treatment parameters: 20 Hz, 20 trains of 2 seconds, 30 seconds between trains, and 80% motor threshold. The effect of rTMS on depression was rated repeatedly with the 17-item Hamilton Rating Scale for Depression (HAM-D) during the 2-week period of stimulation and the 12-week follow-up period conducted from 1997 to 2001. RESULTS: We found a modest, clinically nonrelevant decrease in HAM-D scores in both rTMS and sham patients over 2 weeks of treatment. However, over the subsequent 12-week follow-up, the rTMS group continued to improve significantly compared with the placebo group. CONCLUSION: Decrease of depressive symptoms may continue after the cessation of rTMS stimulation.

Distal neuralgic amyotrophy.

Neuralgic amyotrophy consists of severe pain around the shoulder and arm followed by weakness in one or several muscles of the same area. We describe four patients with distal neuralgic amyotrophy in whom acute, severe, and transient pain around the shoulder or arm was followed by weakness of the forearm and hand muscles only. Minor sensory symptoms were present in only one patient. The presence of structural lesions causing the extent of the forearm and hand motor deficit was excluded by ancillary examinations. Electrophysiological studies showed a motor axonopathy and minimal sensory axonopathy. A follow-up of 2 years or longer showed either spontaneous improvement or residual motor deficit. Unfamiliarity with a clinically distal localization of neuralgic amyotrophy may result in misdiagnosis of lower cervical (poly)radiculopathy in view of the distal localization of the motor deficit and the high prevalence of coincidental abnormalities of the lower cervical spine on plain radiography, computed tomography, or magnetic resonance imaging.

EEG evidence for shunt requirement during carotid endarterectomy: optimal EEG derivations with respect to frequency bands and anesthetic regimen.

Currently there is no consensus on the derivations that should be used for EEG monitoring during carotid endarterectomy (CEA). The aim of this study was to determine which derivations distinguish the best between patients requiring a shunt and patients who do not need a shunt. Four predefined frequency bands and two regimens for general anesthesia (isoflurane versus propofol) were used. EEG data (16 channels) were obtained from 152 EEGs recorded during carotid endarterectomy. Analog EEG signals of preclamp and clamp periods of 100 seconds were digitized to compute power spectra. Changes in power during clamping were calculated for all possible derivations in four predefined frequency bands and were expressed as Z-scores. For each derivation, the area under the receiver operating characteristics curve was calculated. Derivations with the greatest area under the receiver operating characteristics curve were considered to distinguish the best between the shunt and the nonshunt groups formed in retrospect on the basis of consensus between three independent and experienced board-certified electroencephalographers. The two different anesthetic regimens resulted in different patterns of EEG changes because of clamping. The optimal derivations to differentiate between the shunt and the nonshunt groups also differed for the two anesthetic regimens, although for both conditions, anterior head regions were especially preferred. The optimal derivations are given for each anesthetic regimen.

Somatosensory evoked potentials after iohexol myelography.

Tibial nerve and S1 dermatome somatosensory evoked potentials (SSEPs) were recorded before and after iohexol lumbar myelography in order to evaluate possible neurotoxic effects of this contrast medium. No significant change in SSEP latencies nor amplitudes was noted after iohexol myelography, supporting the low neurotoxic profile of this contrast agent. Results were compared to those of a control group of patients before and after lumbar puncture (LP), without injection of contrast agent. In this group also no significant change in SSEP components was found, indicating that a preceding LP does not affect this electrophysiological examination.

Normal values of patellar and ankle tendon reflex latencies.

The clinical value of latency measurement of tendon reflexes in neurological patients has been reported by several authors. However, normal values are not readily comparable. In the present study, latencies and amplitudes of patellar (PTR) and ankle tendon reflexes (ATR) were measured at rest and after facilitation in 102 normal controls. A manually operated reflex hammer, tipped with electrically conductive rubber, ensured an immediate start of the sweep of the oscilloscope. Latencies showed a significant correlation with height (r = 0.70 for PTR and r = 0.72 for ATR, P < 0.0001) and to a lesser degree with age (r = 0.16 and r = 0.30, P < 0.0001). While amplitudes were highly variable, rendering them less useful for diagnostic purposes, latencies showed minimal intra-individual variability (CV 1.5 and 0.8%, respectively). Correlation of ATR-latency with the H-reflex latency of the soleus muscle was very high (r = 0.97, P < 0.0001). Comparison with three other hammer types yielded corresponding results with a hammer supplied with a piezo-electric element; however, significantly shorter latencies were found with a hammer with a microswitch, and with another hammer with a spring-contact, due to a delay from the tap on the tendon until the start of the sweep of the monitor.

Thyroid crisis presenting as coma.

Coma is a rare complication of thyrotoxicosis. A patient with coma due to a thyroid crisis is reported. The EEG showed extremely slow and low voltage activity, which gradually returned to normal. Coma as a presenting symptom of thyroid crisis has not been reported before.

A rare cause of lumbosacral plexus neuropathy.

This is the second report of a case in which a uterine myoma, one of the most common benign tumours of women, was the cause of a lumbosacral plexus neuropathy. The possibility of uterine myoma should be considered in the differential diagnosis of neuropathy of the lumbosacral plexus in women.

Quantitative effects of trunk and head position on the apnea hypopnea index in obstructive sleep apnea.

STUDY OBJECTIVES: To test the hypothesis that head position, separately from trunk position, is an additionally important factor for the occurrence of apnea in obstructive sleep apnea (OSA) patients. DESIGN: Prospective cohort study. SETTING: St. Lucas Andreas Hospital, Amsterdam, the Netherlands. PATIENTS AND PARTICIPANTS: Three hundred patients referred to our department because of clinically suspected OSA. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Patients underwent overnight polysomnography with 2 position sensors: one on the trunk, and one in the mid-forehead. Of the 300 subjects, 241 were diagnosed with OSA, based on an AHI > 5. Of these patients, 199 could be analyzed for position-dependent OSA based on head and trunk position sensors (AHI in supine position twice as high as AHI in non-supine positions): 41.2% of the cases were not position dependent, 52.3% were supine position dependent based on the trunk sensor, 6.5% were supine position dependent based on the head sensor alone. In 46.2% of the trunk supine position-dependent group, head position was of considerable influence on the AHI (AHI was > 5 higher when the head was also in supine position compared to when the head was turned to the side). CONCLUSIONS: The results of this study confirm our hypothesis that the occurrence of OSA may also be dependent on the position of the head. Therefore in patients with a suspicion of position-dependent OSA, sleep recording with dual position sensors placed on both trunk and head should be considered.

The auditory oddball paradigm in patients with vascular cognitive impairment: a prolonged latency of the N2 complex.

OBJECTIVE: The event-related potential (ERP) evoked by the auditory oddball paradigm has been investigated mainly in patients with Alzheimer's disease and in patients with different causes of subcortical dementia. Subcortical ischemic vascular disease (SIVD) seems to be an important cause of vascular cognitive impairment (VCI) frequently not fulfilling the criteria for dementia. Recognition of VCI is needed in order to provide adequate care and therapy. The aim of this study was to investigate the diagnostic value of the different elements of this response (N(1), N(2) complex and P(3) latencies) in a group of elderly patients with VCI caused by SIVD. METHODS: The study population consisted of patients with a clinical and neuropsychological diagnosis of VCI caused by SIVD (n = 38) and healthy control subjects (n = 53) aged 60 years or older. The mean Mini Mental State Examination score of both groups was 27.6, and the mean HIV Dementia Scale score was 6.1 in the patient group and 12.3 in the control group. In all subjects, the ERP was recorded under standardized conditions, and the latencies and amplitudes of N(1), N(2) and P(3) were analyzed by two clinical neurophysiologists in consensus. Both were blinded to the diagnosis. RESULTS: The N(2) latency was significantly longer in patients with VCI than in age-matched controls, whereas the latencies of the P(3) and N(1) were not significantly different. The peak-to-peak amplitude of the N(2) complex to the P(3) wave was significantly lower in the patient group. White matter abnormalities on MRI were not significantly correlated with the N(2) latency. CONCLUSION: Our findings suggest that the latency of the N(2) complex is prolonged and the peak-to-peak amplitude of the N(2) complex to the P(3) wave is lowered in patients with VCI caused by SIVD.

Emboli rate during and early after carotid endarterectomy after a single preoperative dose of 120 mg acetylsalicylic acid--a prospective double-blind placebo controlled randomised trial.

PURPOSE: To investigate whether a single pre-operative dose of 120 mg acetylsalicylic acid (ASA) decreased either (1) emboli rate, as detected by transcranial Doppler (TCD), during and early after carotid endarterectomy (CEA) and (2) clinical intra- and post-operative signs suggestive of embolism or increased bleeding tendency. DESIGN: Prospective, double-blind placebo controlled trial. PATIENTS AND METHODS: One-hundred consecutive patients were randomised to receive either 120 mg ASA (n = 48) or placebo (n = 49) by suppository on the night before CEA; three patients were excluded. Emboli were counted and expressed as emboli rate (ER). The incidence of bleeding complications was assessed. Surgeons were asked to indicate which patients had received ASA or placebo. RESULTS: There were no significant differences between the ASA and placebo groups in ER in the intraoperative and postoperative periods. ER higher than 0.9 min(-1) was associated with a significantly increased risk of complications (26 vs. 0%, P < 0.01). No extra bleeding complications were observed in the ASA group. Surgeon assessment of whether or not ASA had been administered had a sensitivity of 42% and a specificity of 70%. CONCLUSION: A single pre-operative dose of ASA (120 mg) did not reduce significantly the emboli rate during and after CEA and surgeons could not correctly identify whether or not ASA had been administered.