Diagnostics and current care of myasthenia gravis.

Myasthenia gravis (MG) is the most common neuromuscular transmission disorder, causing weakness of skeletal muscles on exertion. The course of the disease is highly variable, symptoms and signs may change rapidly due to infection or pregnancy. MG is classified using serological, electrophysiological and pharmaceutical tools. A precise diagnosis allows for the choice of right treatment, predicts the course of disease and hence helps with the follow-up. In this review we present Finnish guidelines for diagnostics, treatment and follow-up of MG patients.

Progressive cranial nerve involvement and grading of facial paralysis in gelsolin amyloidosis.

INTRODUCTION: Hereditary gelsolin amyloidosis (GA) is a rare condition caused by the gelsolin gene mutation. The diagnostic triad includes corneal lattice dystrophy (type 2), progressive bilateral facial paralysis, and cutis laxa. Detailed information on facial paralysis in GA and the extent of cranial nerve injury is lacking. METHODS: 29 GA patients undergoing facial corrective surgery were interviewed, examined, and studied electroneurophysiologically. RESULTS: All showed dysfunction of facial (VII) and trigeminal (V) nerves, two-thirds of oculomotor (III) and hypoglossal (XII) nerves, and half of vestibulocochlear (acoustic) (VIII) nerve. Clinical involvement of frontal, zygomatic, and buccal facial nerve branches was seen in 97%, 83%, and 52% of patients, respectively. Electromyography showed marked motor unit potential loss in facial musculature. CONCLUSIONS: Cranial nerve involvement in GA is more widespread than previously described, and correlates with age, severity of facial paralysis, and electromyographic findings. We describe a grading method for bilateral facial paralysis in GA, which is essential for evaluation of disease progression and the need for treatment.

Frontal electroencephalogram variables are associated with the outcome and stage of hepatic encephalopathy in acute liver failure.

Acute liver failure (ALF) and hepatic encephalopathy (HE) can lead to an elevated intracranial pressure (ICP) and death within days. The impaired liver function increases the risks of invasive ICP monitoring, whereas noninvasive methods remain inadequate. The purpose of our study was to explore reliable noninvasive methods of neuromonitoring for patients with ALF in the intensive care unit (ICU) setting; more specifically, we wanted to track changes in HE and predict the outcomes of ALF patients treated with albumin dialysis. The study included 20 patients with severe ALF at admission who had been referred to the ICU of the liver transplantation (LT) center for albumin dialysis treatment and evaluation for transplantation. Data were collected from all study patients in the form of continuous frontal electroencephalography (EEG) recordings and transcranial Doppler (TCD) measurements of cerebral blood flow. Among the studied EEG variables, the 50% spectral edge frequency decreased and the delta power increased as the HE stage increased. Both variables were predictive of the stage of HE [prediction probability (PK) of 50% spectral edge frequency = 0.23, standard error (SE) = 0.03; PK of delta power = 0.76, SE = 0.03]. The total wavelet subband entropy, a novel variable that we used for tracking abnormal EEG activity, predicted the outcome of ALF patients treated with albumin dialysis (PK = 0.88, SE = 0.09). With a threshold value of 1.6, the TCD pulsatility index had an odds ratio of 1.1 (95% confidence interval = 0.1-9.3) for a poor outcome (LT or death). In conclusion, EEG variables are useful for the monitoring of HE and can be used to predict outcomes of ALF. TCD measurements do not predict patient outcomes.

Screening of snoring with an MP3 recorder.

PURPOSE: Snoring patients seeking medical assistance represent a wide range of clinical and sleep study findings from nonsleepy nonapneic snoring to severe obstructive sleep apnea syndrome. The prevalence of snoring is high and it significantly impacts quality of life. Its objective diagnosis usually requires a sleep study. We developed a system to analyze snoring sounds with a Moving Picture Experts Group Layer-3 Audio (MP3) recorder device and present its value in the screening of snoring. METHODS: We recorded snoring sounds during in-lab polysomnography (PSG) in 200 consecutive patients referred for a suspicion of obstructive sleep apnea. Snoring was recorded during the PSG with two microphones: one attached to the throat and the other to the ceiling; an MP3 device was attached to the patient's collar. Snoring was confirmed when the MP3 acoustic signal exceeded twice the median value of the acoustic signal for the entire recording. Results of the MP3 snoring recording were compared to the snoring recordings from the PSG. RESULTS: MP3 recording proved technically successful for 87% of the patients. The Pearson correlation between PSG snoring and MP3 snoring was highly significant at 0.77 (p < 0.001). The MP3 recording device underestimated the snoring time by a mean ± SD of 32 ± 55 min. CONCLUSIONS: The recording of snoring with an MP3 device provides reliable information about the patient's snoring.

Recovery of brachial plexus lesions resulting from heavy backpack use: a follow-up case series.

BACKGROUND: Brachial plexus lesions as a consequence of carrying a heavy backpack have been reported, but the typical clinical course and long-term consequences are not clear. Here we evaluated the clinical course and pattern of recovery of backpack palsy (BPP) in a large series of patients. METHODS: Thirty-eight consecutive patients with idiopathic BPP were identified from our population of 193,450 Finnish conscripts by means of computerised register. A physiotherapist provided instructions for proper hand use and rehabilitative exercises at disease onset. The patients were followed up for 2 to 8 years from the diagnosis. We also searched for genetic markers of hereditary neuropathy with pressure palsies. Mann-Whitney U-test was used to analyze continuous data. The Fischer's exact test was used to assess two-way tables. RESULTS: Eighty percent of the patients recovered totally within 9 months after the onset of weakness. Prolonged symptoms occurred in 15% of the patients, but daily activities were not affected. The weight of the carried load at the symptom onset significantly affected the severity of the muscle strength loss in the physiotherapeutic testing at the follow-up. The initial electromyography did not predict recovery. Genetic testing did not reveal de novo hereditary neuropathy with pressure palsies. CONCLUSIONS: The prognosis of BPP is favorable in the vast majority of cases. Electromyography is useful for diagnosis. To prevent brachial plexus lesions, backpack loads greater than 40 kg should be avoided.

Hypothermia-treated cardiac arrest patients with good neurological outcome differ early in quantitative variables of EEG suppression and epileptiform activity.

OBJECTIVE: To evaluate electroencephalogram-derived quantitative variables after out-of-hospital cardiac arrest. DESIGN: Prospective study. SETTING: University hospital intensive care unit. PATIENTS: Thirty comatose adult patients resuscitated from a witnessed out-of-hospital ventricular fibrillation cardiac arrest and treated with induced hypothermia (33 degrees C) for 24 hrs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Electroencephalography was registered from the arrival at the intensive care unit until the patient was extubated or transferred to the ward, or 5 days had elapsed from cardiac arrest. Burst-suppression ratio, response entropy, state entropy, and wavelet subband entropy were derived. Serum neuron-specific enolase and protein 100B were measured. The Pulsatility Index of Transcranial Doppler Ultrasonography was used to estimate cerebral blood flow velocity. The Glasgow-Pittsburgh Cerebral Performance Categories was used to assess the neurologic outcome during 6 mos after cardiac arrest. Twenty patients had Cerebral Performance Categories of 1 to 2, one patient had a Cerebral Performance Categories of 3, and nine patients had died (Cerebral Performance Categories of 5). Burst-suppression ratio, response entropy, and state entropy already differed between good (Cerebral Performance Categories 1-2) and poor (Cerebral Performance Categories 3-5) outcome groups (p = .011, p = .011, p = .008) during the first 24 hrs after cardiac arrest. Wavelet subband entropy was higher in the good outcome group between 24 and 48 hrs after cardiac arrest (p = .050). All patients with status epilepticus died, and their wavelet subband entropy values were lower (p = .022). Protein 100B was lower in the good outcome group on arrival at ICU (p = .010). After hypothermia treatment, neuron-specific enolase and protein 100B values were lower (p = .002 for both) in the good outcome group. The Pulsatility Index was also lower in the good outcome group (p = .004). CONCLUSIONS: Quantitative electroencephalographic variables may be used to differentiate patients with good neurologic outcomes from those with poor outcomes after out-of-hospital cardiac arrest. The predictive values need to be determined in a larger, separate group of patients.

[EEG examination in emergency medicine and analysis of unconciousness]. / Elektroenkefalografia päivystyslääketieteessä ja tajuttomuuden selvittelyssä.

For a long time, the EEG examination has been used as a laboratory examination especially in the diagnostics of epilepsy, but both technical difficulties and problems in interpretation have limited its use in emergency medicine outside special neurological intensive care units. Development of monitoring technology and easier data transfer is making EEG monitoring possible also in the emergency area. The greatest need focuses on the diagnostics and treatment of status epilepticus underlying an unclear unconsciousness. In other indications the usually required information can be obtained by daytime measurements.

[Update on current care guidelines. The treatment of status epilepticus]. / Pitkittynyt epileptinen kohtaus.

Status epilepticus is a medical emergency. Most epileptic seizures last for 1-4 minutes and seizures lasting over five minutes, should be treated as status epilepticus. EEG is essential for diagnostics and the monitoring of treatment effect. The treatment for status epilepticus, irrespective of aetiology, can be divided into first-aid medications, such as buccal midazolam or rectal diazepam, first-line medications such as intravenous diazepam or lorazepam, and second-line medications such as fosphenytoin and valproate for adults and phenobarbital for children. Third-line treatment is suppressive general anaesthesia, monitored by continuous EEG. Antiepileptic medication of patients with epilepsy should be carefully re-evaluated after episode of status epilepticus.

Severe ataxia with neuropathy in hereditary gelsolin amyloidosis: a case report.

Hereditary gelsolin amyloidosis (AGel amyloidosis) is a systemic disorder caused by a G654A or G654T gelsolin mutation, reported from Europe, North America, and Japan. Principal clinical signs are corneal lattice dystrophy, cutis laxa and cranial neuropathy, often deleterious at advanced age. Peripheral neuropathy, if present, is usually mild. We report a 78-year-old male Finnish patient who presented with ataxia and mainly sensory peripheral polyneuropathy (PNP) signs, causing severe disability and ambulation loss. Electrophysiological studies showed severe generalized chronic mainly axonal sensorimotor PNP with facial paralysis. In magnetic resonance imaging proximal lower limb and axial muscle atrophy with fatty degeneration as well as moderate spinal cord atrophy were seen. A G654A gelsolin mutation was demonstrated but no other possible causes of his disability were found. At age 79 years he became bedridden and died of pulmonary embolism. Neuropathological examination revealed marked gelsolin amyloid deposition at vascular and connective tissue sites along the entire length of the peripheral nerves extending to the spinal nerve roots, associated with severe degeneration of nerve fibers and posterior columns. Our report shows that advanced AGel amyloidosis due to degeneration of central and distal sensory nerve projections results in deleterious ataxia with fatal outcome. Severe posterior column atrophy may reflect radicular AGel deposition, although even altered gelsolin-actin interactions in neural cells possibly contribute to neurodegeneration with successive ataxia in carriers of a G654A gelsolin mutation.

Entropy is more resistant to artifacts than bispectral index in brain-dead organ donors.

OBJECTIVE: To evaluate the usefulness of entropy and the bispectral index (BIS) in brain-dead subjects. DESIGN AND SETTING: A prospective, open, nonselective, observational study in the university hospital. PATIENTS AND PARTICIPANTS: 16 brain-dead organ donors. INTERVENTIONS: Time-domain electroencephalography (EEG), spectral entropy of the EEG, and BIS were recorded during solid organ harvest. MEASUREMENTS AND RESULTS: State entropy differed significantly from 0 (isoelectric EEG) 28%, response entropy 29%, and BIS 68% of the total recorded time. The median values during the operation were state entropy 0.0, response entropy 0.0, and BIS 3.0. In four of 16 organ donors studied the EEG was not isoelectric, and nonreactive rhythmic activity was noted in time-domain EEG. After excluding the results from subjects with persistent residual EEG activity state entropy, response entropy, and BIS values differed from zero 17%, 18%, and 62% of the recorded time, respectively. Median values were 0.0, 0.0, and 2.0 for state entropy, response entropy, and BIS, respectively. The highest index values in entropy and BIS monitoring were recorded without neuromuscular blockade. The main sources of artifacts were electrocauterization, 50-Hz artifact, handling of the donor, ballistocardiography, electromyography, and electrocardiography. CONCLUSION: Both entropy and BIS showed nonzero values due to artifacts after brain death diagnosis. BIS was more liable to artifacts than entropy. Neither of these indices are diagnostic tools, and care should be taken when interpreting EEG and EEG-derived indices in the evaluation of brain death.

Dysphonia and dysphagia after anterior cervical decompression.

OBJECT: In this paper, the authors investigate the effects of anterior cervical decompression (ACD) on swallowing and vocal function. METHODS: The study comprised 114 patients who underwent ACD. The early group (50 patients) was examined immediately pre- and postoperatively, and the late group (64 patients) was examined at only 3 to 9 months postoperatively. Fifty age- and sex-matched patients from the Department of Otorhinolaryngology-Head and Neck Surgery who had not been intubated in the previous 5 years were used as a control group. All patients in the early and control groups were examined by a laryngologist; patients in the late group were examined by a laryngologist and a neurosurgeon. Videolaryngostroboscopy was performed in all members of the patient and control groups, and the function of the ninth through 12th cranial nerves were clinically evaluated. Data were collected concerning swallowing, voice quality, surgery results, and health-related quality of life. Patients with persistent dysphonia were referred for phoniatric evaluation and laryngeal electromyography (EMG). Those with persistent dysphagia underwent transoral endoscopic evaluation of swallowing function and videofluorography. RESULTS: Sixty percent of patients in the early group reported dysphonia and 69% reported dysphagia at the immediate postoperative visit. Unilateral vocal fold paresis occurred in 12%. The prevalence of both dysphonia and dysphagia decreased in both groups 3 to 9 months postoperatively. All six patients with vocal fold paresis in the early group recovered, and in the late group there were two cases of vocal fold paresis. The results of laryngeal EMG were abnormal in 14 of 16 patients with persistent dysphonia. Neither intraoperative factors nor age or sex had any effect on the occurrence of dysphonia, dysphagia, or vocal fold paresis. Most patients were satisfied with the surgical outcome. CONCLUSIONS: Dysphonia, dysphagia, and vocal fold paresis are common but usually transient complications of ACD. Recurrent laryngeal nerve damage detected by EMG is not rare. Pre-and postoperative laryngeal examination of ACD patients should be considered.

Snoring is not relieved by nasal surgery despite improvement in nasal resistance.

OBJECTIVES: In the present study, we evaluated the effect of nasal surgery on snoring time, snoring intensity, and sleep-disordered breathing. The role of abnormal cephalometry in treatment outcome was assessed. DESIGN: A cross-sectional prospective study. SETTING: University teaching hospital. PATIENTS: Forty consecutive snoring men who were referred to ENT Hospital because of a snoring problem or suspicion of sleep apnea. INTERVENTIONS: The patients underwent anterior rhinomanometry and polysomnography (PSG) with recording of snoring before and after operative treatment of nasal obstruction. Cephalometric radiographs were obtained before surgery. RESULTS: Nasal resistance decreased significantly in the overall patient group. Snoring time, snoring intensity, nocturnal breathing, and sleep architecture did not change after nasal surgery. Cephalometry did not predict operative outcome in these patients. Snoring intensity was found to be significantly higher during non-rapid eye movement (NREM) sleep than during rapid eye movement sleep. CONCLUSIONS: Operative treatment of mainly structural nasal obstruction did not seem to decrease snoring intensity, snoring time, or sleep-disordered breathing in an objective assessment by PSG performed after surgery. The effect of treating inflammatory nasal changes during nocturnal breathing, as well as the role of cephalometry in the prediction of treatment outcome will need further evaluation. Higher snoring intensity related to NREM sleep may add to the sleep disturbance of a bed partner in the evening.

Predicting Obstructive Sleep Apnea with Periodic Snoring Sound Recorded at Home.

STUDY OBJECTIVES: The cost-effectiveness of diagnosing obstructive sleep apnea (OSA) could be improved by using a preliminary screening method among subjects with no suspicion of other sleep disorders. We aimed to evaluate the diagnostic value of periodic snoring sound recorded at home. METHODS: We included 211 subjects, aged 18-83 (130 men), who were referred to our laboratory for suspicion of OSA, and had a technically successful overnight polygraphy, measured with the Nox T3 Sleep Monitor (Nox Medical, Iceland) with a built-in microphone. We analyzed the percentage of periodic snoring during the home sleep apnea study. RESULTS: Apnea-hypopnea index (AHI) ranged from 0.1 to 116 events/h and the percentage of periodic snoring from 1% to 97%. We found a strong positive correlation (r = 0.727, p < 0.001) between periodic snoring and AHI. The correlation was slightly stronger among female, younger, and obese subjects. The best threshold value of the periodic snoring for predicting an AHI > 15 events/h with as high sensitivity as possible was found to be 15%. There, sensitivity was 93.3%, specificity 35.1%, and negative predictive value 75.0%. CONCLUSIONS: According to our results, it is possible to set a periodic snoring threshold (15% or more) for the subject to advance to further sleep studies. Together with medical history and prior to more expensive studies, measuring periodic snoring at home is a simple and useful method for predicting the probability of OSA, in particular among women who are often unaware of their apnea-related snoring.

Decreased Aerobic Capacity in ANO5-Muscular Dystrophy.

BACKGROUND: Anoctaminopathies are muscle diseases caused by recessive mutations in the ANO5 gene. The effects of anoctaminopathy on oxidative capacity have not previously been studied in a controlled setting. OBJECTIVE: To characterize oxidative capacity in a clinically and genetically well-defined series of patients with anoctaminopathy. METHODS: We sequenced the ANO5 gene in 111 Finnish patients with suspected LGMD2. Patients with positive findings underwent close clinical examination, including electromyography, muscle MRI, and, in selected cases, muscle biopsy. Oxidative capacity was analyzed using spiroergometry and compared to age-matched healthy controls. RESULTS: We characterized 12 newly identified and 2 previously identified patients with ANO5 mutations from 11 families. Our material was genetically homogeneous with most patients homozygous for the Finnish founder variant c.2272C>T (p.Arg758Cys). In one family, we found a novel p.Met470Arg variant compound heterozygous with p.Arg758Cys. Lower limb muscle MRI revealed progressive fatty degeneration of specific posterior compartment muscles. Patients' spiroergometric profiles showed that anoctaminopathy significantly impaired oxidative capacity with increasing ventilation. CONCLUSIONS: Our findings support earlier reports that anoctaminopathy progresses slowly and demonstrate that the disease impairs the capacity for aerobic exercise.

Patient- and bed partner-reported symptoms, smoking, and nasal resistance in sleep-disordered breathing.

OBJECTIVES: Nocturnal and daytime symptoms are important determinants in clinical decision making in patients suspected of having sleep-disordered breathing (SDB). We compared patients' and bed partners' reporting of symptoms associated with SDB in a clinical sample of snoring men. The bed partners' view on snoring disturbance was assessed. The relationship between sleep parameters, anthropometric data, and selected subjective symptoms was assessed. Additionally, we evaluated the relationship between smoking, nasal resistance, and habitual snoring. DESIGN: A cross-sectional, prospective study. SETTING: University teaching hospital. PATIENTS: Thirty-seven consecutive snoring men referred to ENT Hospital because of a snoring problem or suspicion of sleep apnea, and scheduled for surgical treatment of nasal obstruction. INTERVENTIONS: The patients completed a sleep questionnaire, a questionnaire on nasal history, and the Epworth sleepiness scale. The bed partners were asked to complete a separate sleep questionnaire of the patient's daytime and nocturnal symptoms. Both patients and bed partners evaluated the intensity of snoring on a visual analog scale. The patients underwent polysomnography and anterior rhinomanometry. RESULTS: Agreement of patients' and bed partners' reports on symptoms related to SDB was good in this material. One half of the bed partners were disturbed by snoring every night or almost every night, and one third of the bed partners reported disharmony in the relationship from time to time or repeatedly due to snoring. The combination of current smoking and total nasal resistance in a supine position higher than the median value in this patient sample was associated with history of habitual snoring. CONCLUSIONS: Male patients and their bed partners seem to give congruent reports of snoring and symptoms related to SDB in a clinical population with mild SDB. One half of the bed partners found their sleep constantly disturbed. The combination of current smoking and high nasal resistance was related with habitual snoring.

Quantitative electroencephalographic measures in homicidal men with antisocial personality disorder.

Many symptoms of antisocial personality disorder have been proposed to be related to decreased daytime vigilance. To explore this hypothesis, quantitative analyses were conducted of the electroencephalographic (EEG) activity of drug-free and detoxified homicidal male offenders with antisocial personality disorder as the primary diagnosis. Subjects comprised 16 men recruited from a forensic psychiatric examination in a special ward of a university psychiatric hospital. Fifteen healthy age- and gender-matched controls with no criminal record or history of physical violence consisted of hospital staff and students. An overall reduction of alpha power was observed in the waking EEG of offenders. A bilateral increase in occipital delta and theta power was also found in these individuals. This study provides further support to the growing evidence of brain dysfunction in severe aggressive behavior. Homicidal offenders with antisocial personality disorder seem to have difficulties in maintaining normal daytime arousal. Decreased vigilance, together with social and psychological variables, may explain their aberrant behavior in everyday life. New studies are, however, needed to specify the vigilance problems of this patient group.

Intravenous lipid emulsion given to volunteers does not affect symptoms of lidocaine brain toxicity.

Intravenous lipid emulsion has been suggested as treatment for local anaesthetic toxicity, but the exact mechanism of action is still uncertain. Controlled studies on the effect of lipid emulsion on toxic doses of local anaesthetics have not been performed in man. In randomized, subject-blinded and two-phase cross-over fashion, eight healthy volunteers were given a 1.5 ml/kg bolus of 20% Intralipid(®) (200 mg/ml) or Ringer's acetate solution intravenously, followed by a rapid injection of lidocaine 1.0 mg/kg. Then, the same solution as in the bolus was infused at a rate of 0.25 ml/kg/min. for 30 min. Electroencephalography (EEG) was recorded, and 5 min. after lidocaine injection, the volunteers were asked to report subjective symptoms. Total and un-entrapped lidocaine plasma concentrations were measured from venous blood samples. EEG band power changes (delta, alpha and beta) after the lidocaine bolus were similar during lipid and during Ringer infusion. There were no differences between infusions in the subjective symptoms of central nervous system toxicity. Lidocaine was only minimally entrapped in the plasma by lipid emulsion, but the mean un-entrapped lidocaine area under concentration-time curve from 0 to 30 min. was clearly smaller during lipid than Ringer infusion (16.4 versus 21.3 mg × min/l, p = 0.044). Intravenous lipid emulsion did not influence subjective toxicity symptoms nor affect the EEG changes caused by lidocaine.

Esophageal pressure monitoring in detection of sleep-disordered breathing.

OBJECTIVE: The aim was to study the value of esophageal pressure monitoring combined with limited polygraphic recording (oxygen saturation, respiratory and leg movements, airflow, body position, and snoring sound) in diagnosis of sleep-disordered breathing. STUDY DESIGN: A prospective study of consecutive patients with snoring was carried out. METHODS: Sixty-seven patients underwent an overnight study on ward. Patients with normal oxygen desaturation index and any periodic breathing disturbances combined with elevated esophageal pressure were further studied with complete polysomnography. RESULTS: The patient compliance with esophageal catheter was 87%. Esophageal pressure monitoring increased effectively the detection of sleep-disordered breathing with limited polygraphic recording. Sixty-seven percent of the patients with normal oxygen desaturation index and respiratory-related esophageal pressure variation had sleep-disordered breathing on complete polysomnography. Increased esophageal pressure variation was significantly related with oxygen desaturation index and obstructive sleep apnea diagnosis (P <.001). All together, 48% of the mainly nonobese snorers had objective findings of sleep-disordered breathing. Patients with upper airway resistance syndrome were few. Fifteen percent of the patients had periodic leg movements. Neither subjective or objective sleepiness nor snoring or obesity adequately exposed sleep-disordered breathing in this material. CONCLUSION: Esophageal pressure monitoring increases markedly the diagnostic value of limited polygraphic recording as a screening study for sleep-disordered breathing.

Postural cephalometric analysis and nasal resistance in sleep-disordered breathing.

OBJECTIVES: The study was designed to compare upright and supine cephalometric measurements in snorers and to evaluate the effects of mandibular position and nasal resistance on pharyngeal dimensions. Anthropometric, rhinomanometric, and cephalometric measurements were used to investigate predictors of apnea-hypopnea index. STUDY DESIGN: Prospective, cross-sectional. METHODS: Forty consecutive habitually snoring men waiting for nasal surgery (mean age, 44 y; mean body mass index, 28 kg/m2) underwent an overnight polysomnographic, anterior rhinomanometric, and cephalometric analysis in upright and supine positions. RESULTS: Nasal resistance correlated positively with minimal pharyngeal airspace at the level of tongue. The opening of jaws after voluntary relaxation of the mandibular position on lying down correlated with decrease in pharyngeal airway measurements at both velopharyngeal and tongue-base levels. In stepwise multiple regression analysis the overall patient model explained 68% of the variation in apnea-hypopnea index with body mass index as the largest predictor. In the nonobese patients, the model explained 86% of variation in apnea-hypopnea index with change in anteroposterior position of the lower jaw in upright and supine measurements and combined nasal resistance after mucosal decongestion as independent determinants. In selected skeletal subtypes the models predicted 83%, 79%, 61%, and 90% of the variation in apnea-hypopnea index. CONCLUSIONS: In the nonobese patients nasal resistance and change in mandibular position on lying down were found to be independent contributing factors to the apnea-hypopnea index. Further research on supine cephalometry and relaxed mandibular position may improve prediction of sleep-disordered breathing in snorers.