Evidence of a nonlinear human magnetic sense.

Human subjects respond to low-intensity electric and magnetic fields. If the ability to do so were a form of sensory transduction, one would expect that fields could trigger evoked potentials, as do other sensory stimuli. We tested this hypothesis by examining electroencephalograms from 17 subjects for the presence of evoked potentials caused by the onset and by the offset of 2 G, 60 Hz (a field strength comparable to that in the general environment). Both linear (time averaging) and nonlinear (recurrence analysis) methods of data analysis were employed to permit an assessment of the dynamical nature of the stimulus/response relationship. Using the method of recurrence analysis, magnetosensory evoked potentials (MEPs) in the signals from occipital derivations were found in 16 of the subjects (P<0.05 for each subject). The potentials occurred 109-454 ms after stimulus application, depending on the subject, and were triggered by onset of the field, offset of the field, or both. Using the method of time averaging, no MEPs were detected. MEPs in the signals from the central and parietal electrodes were found in most subjects using recurrence analysis, but no MEPs were detected using time averaging. The occurrence of MEPs in response to a weak magnetic field suggested the existence of a human magnetic sense. In distinction to the evoked potentials ordinarily studied, MEPs were nonlinearly related to the stimulus as evidenced by the need to employ a nonlinear method to detect the responses.

Neurology patient education materials: do our educational aids fit our patients' needs?

The purpose of this study was to assess the suitability of various neurology patient education brochures, as well as neurology information on the World Wide Web, to determine whether they were appropriate for patients with low literacy. A convenience sample of 520 patients in university-based public and private neurology clinics participated. In this cross-sectional study, the patients' reading levels were assessed by using the Rapid Estimate of Adult Literacy in Medicine. Forty-three patient education materials were assessed for reading level by using the Fog Index and for suitability characteristics (including content, type and relevance of graphics, layout, type size and fonts, and motivating qualities) by using the Suitability Assessment of Materials. The mean education level of patients was 12th grade; however, the mean reading level was 7th-8th grade. Of the assessed materials, 91% were written at a 9th-grade level or above, even though only 58% of patients read at a 9th-grade level. Only 14% of the materials were considered to have superior suitability, whereas 58% were adequate, and 28% were determined not suitable. Thus, the available neurology patient education aids are not matched to the patient population or to the average U.S. reading levels. Ideally, information needs to be written at a 9th-grade level or below. Instructional graphics, simpler words, patient interaction, and cultural sensitivity improve material suitability.

Comparing the effectiveness of video and written material for improving knowledge among sleep disorders clinic patients with limited literacy skills.

BACKGROUND: Health care professionals often use written material or video recordings to teach their patients without knowing which is more effective for comprehension of the information. METHODS: Patients watched either an instructional videotape about sleep apnea or read a newly designed brochure, then responded to a structured questionnaire containing 11 knowledge-based questions and 1 open-ended question (requesting suggestions for improvement of the brochure or videotape). RESULTS: Mean reported educational level was grade 12, and mean reading level was between grade 7 and 8. Using video significantly improved only two areas of knowledge for low-level (below grade 8) readers: defining sleep apnea (66% vs 43%) and identifying what continuous positive airway pressure (CPAP) does for the patient (94% vs 78%). Patients requested material with more diverse cultural representation, more information on treatment and outcomes, and fewer polysyllabic words. CONCLUSIONS: Emphasis on diagnosis and treatment, explained using simple words, should be reflected in the content of patient education brochures or videos. Providing information by video alone may have limited benefits.

Practice parameters for the treatment of restless legs syndrome and periodic limb movement disorder. An American Academy of Sleep Medicine Report. Standards of Practice Committee of the American Academy of Sleep Medicine.

These are the first clinical guidelines published for the treatment of Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) providing evidence-based practice parameters. They were developed by the Standards of Practice Committee and reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine. The guidelines provide recommendations for the practice of sleep medicine in North America regarding the treatment of RLS and PLMD. Recommendations are based on the accompanying comprehensive review of the medical literature regarding treatment of RLS and PLMD which was developed by a task force commissioned by the American Academy of Sleep Medicine. Recommendations are identified as standards, guidelines, or options, based on the strength of evidence from published studies that meet criteria for inclusion. Dopaminergic agents are the best studied and most successful agents for treatment of RLS and PLMD. Specific recommendations are also given for the use of opioid, benzodiazepine, anticonvulsant, and adrenergic medications, and for iron supplementation. In general, pharmacological treatment should be limited to individuals who meet diagnostic criteria and especially who experience insomnia and/or excessive sleepiness that is thought to occur secondary to RLS or PLMD. Individuals treated with medication should be followed by a physician and monitored for clinical response and adverse effects. It would be desirable for future investigations to employ multicenter clinical trials, with expanded numbers of subjects using double-blind, placebo-controlled designs, and an assessment of long-term response, side effects, and impact of treatment on quality of life. Evaluation of special groups such as children, pregnant women, and the elderly is warranted.

Practice parameters for the use of light therapy in the treatment of sleep disorders. Standards of Practice Committee, American Academy of Sleep Medicine.

These clinical guidelines were developed by the Standards of Practice Committee and reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine. The guidelines provide recommendations for the practice of sleep medicine in North America regarding the use of light therapy for treatment of various sleep disorders. This paper is based on a series of articles in the Journal of Biological Rhythms and also includes evidence tables from an updated Medline review covering the period January 1994 to December 1997. Evidence is presented by grade and level. Recommendations are identified as standards, guidelines, or options. Recommendations are provided for delayed sleep phase syndrome (DSPS), advanced sleep phase syndrome (ASPS), non-24-hour sleep-wake syndrome, jet lag, shift work, dementia, and sleep complaints in the healthy elderly. Light therapy appears generally safe if used within recommended intensity and time limits. Light therapy can be useful in treatment of DSPS and ASPS. Benefits of light therapy are less clear and treatment is an option in jet lag, shift work, and non-24-hour sleep-wake syndrome in some blind patients.

Practice parameters for the nonpharmacologic treatment of chronic insomnia. An American Academy of Sleep Medicine report. Standards of Practice Committee of the American Academy of Sleep Medicine.

Insomnia is the most common sleep complaint reported to physicians. Treatment has traditionally involved medication. Behavioral approaches have been available for decades, but lack of physician awareness and training, difficulty in obtaining reimbursements, and questions about efficacy have limited their use. These practice parameters review the current evidence with regards to a variety of nonpharmacologic treatments for insomnia. Using a companion paper which provides a background review, the available literature was analyzed. The evidence was graded by previously reported criteria of the American Academy of Sleep Medicine with references to American Psychological Association criteria. Treatments considered include: stimulus control, progressive muscle relaxation, paradoxical intention, biofeedback, sleep restriction, multicomponent cognitive behavioral therapy, sleep hygiene education, imagery training, and cognitive therapy. Improved experimental design has significantly advanced the process of evaluation of nonpharmacologic treatments for insomnia using guidelines outlined by the American Psychological Association (APA). Recommendations for individual therapies using the American Academy of Sleep Medicine recommendation levels for each are: Stimulus Control (Standard); Progressive Muscle Relaxation, Paradoxical Intention, and Biofeedback (Guidelines); Sleep Restriction, and Multicomponent Cognitive Behavioral Therapy (Options); Sleep Hygiene Education, Imagery Training, and Cognitive Therapy had insufficient evidence to be recommended as a single therapy. Optimal duration of therapy, who should perform the treatments, long term outcomes and safety concerns, and the effect of treatment on quality of life are questions in need of future research.

Obstructive sleep apnea during pregnancy resulting in pulmonary hypertension.

Obesity is known to increase maternal morbidity and mortality. We describe a case of obstructive sleep apnea due to obesity and discuss our treatment of the resulting pulmonary hypertension. A patient was transferred to our hospital at 29 weeks' gestation with severe anasarca and more than a 100-pound weight gain during pregnancy. Pulmonary hypertension due to obstructive sleep apnea was diagnosed. The patient was treated with nasal continuous positive airway pressure (CPAP) during sleep and remained in the hospital the remainder of her pregnancy. She had a massive spontaneous diuresis during her hospital stay and lost more than 100 pounds. She was delivered at term via cesarean section because of transverse lie. Preoperative hemodynamic monitoring confirmed the diagnosis of pulmonary hypertension. This represents the first case in the literature of obstructive sleep apnea leading to pulmonary hypertension in pregnancy. This patient responded well to nasal CPAP as evident by the massive diuresis and good maternal outcome.

Presentation and reading level of sleep brochures: are they appropriate for sleep disorders patients?

OBJECTIVE: Sleep-disorders patients must be given information and health education they understand. The purpose of this study was twofold: (1) to assess suitability of American Sleep Disorders Association and National Sleep Foundation patient education brochures; and (2) to assess one widely used brochure, using patient input and patient literacy level, as a model for development of future materials. DESIGN: Twelve American Sleep Disorders Association and National Sleep Foundation brochures were assessed for reading level using Grammatik, and for design, presentation, and motivating qualities using the Suitability Assessment of Materials (SAM). Patient literacy level was assessed using the Rapid Estimate Of Adult Literacy in Medicine (REALM). SETTING: The Louisiana State University Medical Center sleep clinic, faculty private sleep clinic, and in the sleep center laboratory. PATIENTS OR PARTICIPANTS: During the months of February-May 1997, 170 sleep disorders patients, 39% African American, 59% white participated in the study. Participants ranged in age from 18-73 years, with a mean age of 46. MEASUREMENTS AND RESULTS: Suitability scores for the 12 brochures indicate that none scored in the superior range, 83% scored adequate, and 17% scored not suitable. Ninety-four percent of the brochures were written on a 12th grade level or higher, yet 37% of the sleep patients tested were reading at less than a 9th grade level. Low-level readers were significantly more likely than their higher-reading-level counterparts to report that a brochure was too long (22% vs 12%; p < .05), and that they would need help reading it (44% vs 3%; p < .001). CONCLUSIONS: Patients need sleep information given to them on a level they understand. When developing and selecting appropriate materials, reading level, length, and suitability of written material should be considered.

The indications for polysomnography and related procedures.

This paper is a review of the literature on the use of polysomnography in the diagnosis of sleep disorders in the adult. It is based on a search of MEDLINE from January 1966 through April 1996. It has been reviewed and approved by the Board of Directors of the American Sleep Disorders Association and provides the background for the accompanying ASDA Standards of Practice Committee's Parameters for the Practice of Sleep Medicine in North America. The diagnostic categories reviewed are: sleep-related breathing disorders; other respiratory disorders; narcolepsy; parasomnias and sleep-related epilepsy; restless legs syndrome and periodic limb movement disorders: insomnia; and circadian rhythm sleep disorders. Where appropriate, previously published practice parameters papers are cited and discussed. The relevant published peer-reviewed literature used as the basis for critical decisions was compiled into accompanying evidence tables and is analyzed in the text. In the section on the assessment of sleep apnea syndrome, options for estimating pretest probability to select high risk patients are also reviewed. Sleep-testing procedures other than standard polysomnography are also addressed (daytime polysomnography, split-night studies, oximetry, limited full respiratory recordings, and less-than-full respiratory recording) and treatment-related follow-up studies are discussed.

Frequency-specific responses in the human brain caused by electromagnetic fields.

The effects of 1.5- and 10-Hz electromagnetic fields (EMFs), 0.2-0.4 gauss, on the intrinsic electrical activity of the human brain at these frequencies was studied. Each of 19 subjects exposed for 2-sec epochs exhibited altered brain electrical activity at the frequency of the EMF during the time of stimulation, as determined by spectral analysis of the electroencephalogram. Since brain activity at specific frequencies could be altered by applied EMFs, the results suggest that it may be possible to use EMFs to determine whether particular intrinsic frequencies subserve specific physiological or behavioral responses.

Frequency-specific blocking in the human brain caused by electromagnetic fields.

Based on preliminary observations that continuous exposure to electromagnetic fields (EMFs) produced an after-effect on human brain electrical activity, the effect of 10 Hz, 1 gauss, on the intrinsic activity of the brain at that frequency was studied. Ten subjects were exposed for 10 min and the 10 Hz spectral power was measured during the 1 min interval following stimulation and compared with control values obtained from the same subjects. Significantly reduced brain electrical activity from the occipital electrodes following termination of the EMF exposure was observed, thereby confirming the preliminary results.

Assessment of hypoxemia in patients with sleep disorders using saturation impairment time.

A method of recording cumulative nocturnal oxygen desaturation was utilized to develop a quantitative index of nocturnal hypoxemia (SIT index) to provide reference values and distributional properties for apneic and nonapneic sleep-disordered patients. The SIT indices were compared in patients with varying degrees of obstructive sleep apnea (OSA) as determined by traditional methods of counting apneas and hypopneas. We studied 298 patients who were divided into five groups based on the presence and frequency of apnea or sleep-related respiratory deterioration. SIT indices for patient groups and individual patients were compared with the respiratory disturbance index (apneas + hypopneas x 60/total sleep time = RDI) using scatter plots, Kruskal-Wallis analysis of variance, and Mann-Whitney U tests. The OSA and non-respiratory-impaired patient groups had mean SIT values that were significantly different (p < 0.05). Subjects with severe apnea differed (p < 0.05) from subjects with mild and moderate apnea at SIT index thresholds < baseline, < 90, < 80, and < 70% SaO2, but subjects with mild and moderate apnea did not differ statistically from each other at any threshold. In individual patients with similar RDI values, considerable variation in SIT index can be seen, and the reverse is also true. This suggests that using both RDI and SIT may provide complementary information in assessing the severity of OSA.

Alterations in brain electrical activity caused by magnetic fields: detecting the detection process.

Static and 60 Hz magnetic fields, 0.78 gauss, were applied individually and combined to each of 20 human subjects during 2 sec epochs, and the effect on the EEG was determined by comparing the power spectrum obtained during field exposure with that from control epochs. All but one subject exhibited field-induced alterations in the EEG; most subjects exhibited increased EEG activity at 2 or more frequencies within 1-18.5 Hz. The field-induced changes were recorded more often at the central and parietal electrodes than at the occipital electrodes. The responses observed during application of combined static and alternating fields did not differ from the sum of the responses observed when the fields were applied individually, even though the exposure conditions were specifically chosen to favor the hypothesized ion-resonance mechanism of interaction involving Ca2+. The data support the view that detection loci for magnetic fields exist within the nervous system.

Computer quantitation of saturation impairment time as an index of oxygenation during sleep.

The measurement of oxygenation during sleep has become a standard procedure in the assessment of hypoxemia in patients with various disorders. However, an accepted method for quantitating this hypoxemia is not available. This study describes the development of computerized data acquisition and analysis programs to quantitate nocturnal hypoxemia in patients with sleep and breathing disorders. The acquisition program samples the voltage output from pulse oximeters used to measure oxyhemoglobin saturation (SpO2) and stores this on an IBM PC or compatible computer. The analysis program integrates the SpO2 over time below the patient's pretest baseline as well as the integral below 90, 80, 70, 60 and 50% saturation. We refer to each integral as Saturation Impairment Time or SIT. In order to compare these integrals between patients or between the same patient but different studies, the integral is divided by the total sleep study time. We refer to each of these integrals, corrected for sleep study time, as the SIT index. Evaluation of the SIT index in 10 consecutive patients referred for various sleep disorders revealed acquisition program detection and deletion of 48 of 57 (86%) oximeter probe artifacts (mean duration of 3 seconds for undetected artifacts). There were no significant artifacts in the analysis program calculation of the SIT index in these same patients. In conclusion, computer programs were developed to measure and quantitate oxygen saturation measured by oximeters. Preliminary results reveal an accuracy of measurement which should prove acceptable in further clinical evaluations.

Neuroendocrine evaluation in Kleine-Levin syndrome: evidence of reduced dopaminergic tone during periods of hypersomnolence.

A patient with Kleine-Levin syndrome had polysomnography and neuroendocrinological assays performed during asymptomatic (ASMP) and symptomatic (SMP) 24-hr periods. During the SMP, sleep data revealed poor nocturnal sleep efficiency, increased sleep fragmentation and reduced stages 3, 4 and rapid eye movement (REM). No sleep onset REM episodes were seen. Sleep staging in the ASMP was normal. Blood samples were obtained every 20 min and assayed for thyroid-stimulating hormone (TSH), cortisol (CORT), prolactin (PRL) and growth hormone (GH). Patterns of secretion, 24-hr mean and total integrated concentrations, and mean sleep period time values during the ASMP and SMP were compared. The mean 24-hr level of TSH was increased and GH decreased in the SMP. Comparing sleep period time in the SMP to the ASMP, values for TSH and PRL were increased and GH and CORT were reduced in the SMP. These hormone changes support the hypothesis that reduced hypothalamic dopaminergic tone is present in the SMP compared to the ASMP in Kleine-Levin patients.

Computed tomography number correlations for metrizamide computed tomographic ventriculography.

The authors describe a method that permits the determination of the precise intraventricular iodine concentration after metrizamide computed tomographic ventriculography. There is an observed linear relationship between computed tomography number (Hounsfield units) and iodine concentration. This relationship may be used to provide the basis for a method of evaluating ventricular fluid dynamics. This, in turn, is useful for the determination of the indications for a shunting procedure and for the evaluation of shunt function in a patient with an existing shunt.

Aphasia following a right thalamic hemorrhage.

A left-handed patient with a right thalamic hemorrhage and disordered speech is described. Sequential examinations and aphasia testing were done during a 1-year follow-up period and the results are reported. This case supports those authors who have described characteristics they feel are helpful in diagnosing disordered speech associated with thalamic lesions. Paucity of speech, reduced voice volume, anomia, some paraphasia, and severe dysgraphia were present, but comprehension and repetition were relatively preserved. She showed modest improvement with time. This case also confirms that thalamic involvement in speech is a dominant, rather than a specifically left hemispheric function.

Postictal elevation of serum creatine kinase level.

Serial serum creatine kinase (CK) level determinations were performed on selected patients for six days following tonic-clonic or focal motor seizures in a prospective study. The time course and magnitude of serum CK elevation was correlated with seizure CK level was observed in all patients. Isoenzyme determinations revealed that CK was derived from skeletal muscle. Our data demonstrate that profound elevations of serum CK level may occur postictally and appear to be related to the intensity of muscular activity. patients with seizures associated with alcohol abuse had the greatest postictal serum CK level increases.