Yoshiaki Itasaka

The influence of sleep position and obesity on sleep apnea

The influence of sleep position and the degree of obesity were examined in 257 subjects with sleep apnea. Subjects were divided into three groups according to obesity: normal weight (body mass index (BMI) under 24.0 kg/m 2 ), mild obese (BMI 24.0–26.4 kg/m 2 ) and obese group (BMI 26.4 kg/m 2 and heavier). The apnea + hypopnea index (AHI), the intraesophageal pressure and the lowest oxygen saturation became significantly worse according to the degree of obesity. The subjects were also divided into two groups according to the reduction in the AHI by lateral position: good responders showed 50% or more reduction of AHI in lateral position and poor responders indicated less than 50% reduction. The percentage of good responders to sleep position change was 90.9% in normal weight group, 74.0% in mild obese group and 57.4% in the obese group. The ratio of the subjects who had indicated two or more obstructive sites in normal weight group was 36.0% in good responders and 40.0% in poor responders. The ratio in the mild obese group was 51.8% in good responders and 66.7% in poor responders. In the obese group, the ratio was 59.4% in good responders and 78.9% in poor responders.

Acoustic Analysis of Snoring and the Site of Airway Obstruction in Sleep Related Respiratory Disorders

Seventy-five adult patients with sleep related respiratory disorders were examined by polysomnography with simultaneous recordings of the intraluminal pressure of the upper airway and snoring sound. Obstructed sites in the upper airway during sleep were determined by comparing the amplitude of respiratory fluctuation of the pressures in the epipharynx, mesopharynx, hypopharynx and esophagus. A definite correlation existed between the intensity of snoring sound and the amplitude of respiratory fluctuation of the intraesophageal pressure. Based on the results of the intraluminal pressure partitioning, the subjects were divided into the soft palate type (28), the tonsil/tongue base type (14), the combined type (27) and the larynx type (6). The average value of fundamental frequency (ff) was 102.8+/-34.9 Hz in the soft palate type, 331.7+/-144.8 Hz in the tonsil tongue base type, 115.7+/-58.9 Hz in the combined type and around 250 Hz in the larynx type.

Evaluation of uvulopalatopharyngoplasty in treatment of obstructive sleep apnea syndrome

Many methods have been reported to select the proper candidates for uvulopalatopharyngoplasty (UPPP) among obstructive sleep apnea patients. Polysomnography with intraluminal pressure recordings in the upper airway was found useful to predict obstructive site(s) and hence the success of surgery. According to the pressure analysis, 11 cases with high negative pressure at the mesopharynx were selected for UPPP, while UPPP combined with midline partial glossectomy (UPPP-MLG) was done in 18 cases proved to have high negative pressure difference between the mesopharynx and esophagus. A reduction of the apnea hypopnea index (AHI) of more than 50% after UPPP was found in 8 cases (72.7%) and in 11 cases (61.l%) after UPPP-MLG. It was found that the response rate was lower among the second group if compared to that of the first because of other aggravating factors rather than simple obstruction at the level of the soft palate and or tonsils-tongue base level.

Respiratory disturbance during sleep due to adenoid-tonsillar hypertrophy

The pathophysiologic results of respiratory disturbances caused by adenoid-tonsillar hypertrophy are reported. In each case, we monitored intraesophageal pressure to accurately assess respiratory effort, and recorded a sleep diary to detect disorganized sleep habits and disturbed sleeping-waking rhythms. We noticed that great respiratory effort existed not only during light sleep, but was also continuously observed during deep sleep despite the total disappearance of obstructive apneas. Furthermore, upper airway obstruction caused by adenoid-tonsillar hypertrophy and hypoxemia during sleep in the rapid eye movement stage were found to be closely related to the sudden infant death syndrome. A sleep diary recording sleep habits and regularity of night sleep seems to provide reliable indicators for the determination of surgical intervention.

Influence of alcohol on respiratory disturbance during sleep.

Oxygen saturation was measured in 37 patients with sleep‐related breathing disorders over 2 nights: after alcohol intake and under control conditions. Both the number of 3% oxygen desaturation per hour (ODI3) and the lowest saturation (LSAT) were significantly aggravated after alcohol ingestion. Oxygen saturation was degraded in 28 cases after alcohol intake. In 69% of the cases in which ODI3 increased after alcohol ingestion, the aggravation during the alcohol metabolism time was noted. No correlation was found between the quantity of alcohol and oxygen desaturation following alcohol ingestion. Our study revealed that alcohol aggravates sleep‐related breathing disorders.

Facial pattern categories of sleep breathing-disordered children using Ricketts analysis.

Abstract The facial patterns of 29 children under the age of 15 years with tonsil and/or adenoid and sleep disorder problems was analysed. The lateral‐cephalograms of these patients was digitized in a zero‐based computer program using Ricketts analysis to examine facial patterns. Results of the analysis were compared with the mean of the control group, n = 41 (9‐year‐old Japanese children). There were significant differences (P < 0.01–0.001) between the patient group and the control group when comparing the facial axis, lower facial height, mandibular arc, total facial height, and McNamara–Pogonion. The facial pattern of children with sleep breathing disorders was discovered to be the dolico facial pattern.

Intensity of snoring in patients with sleep-related breathing disorders

The intensity of snoring was measured in 73 patients with snoring or sleep apnea using a noise meter. The mean intensity of snoring at 50 cm in front of the mouth was 61.7 dB in the supine position and 53.7 dB in the lateral position. There existed a definite correlation between the logarithmic transformation of the intra‐esophageal pressure amplitude and the intensity of snoring in the supine and lateral decubitus positions. These findings suggest that the intensity of snoring may be a useful index for sleep‐related breathing disorders.

Gait instability in patients with acoustic neuroma.

Objective To investigate pathological gait in patients with unilateral acoustic neuroma using tactile sensors placed under both feet. Material and Methods Forty-three patients were enrolled in the study. They were categorized into two groups: the small tumor group had tumors<2 cm from the porus acousticus without any brainstem compression and the large tumor group had tumors>2 cm from the porus acousticus with brainstem compression. Eighteen healthy subjects served as controls. Subjects were asked to walk freely with eyes open or closed for a distance of nearly 8 m. The coefficients of variation (CVs) of stance, swing and double support were calculated. The stability of the trajectories of the center of force and the foot pressure difference were also studied. Results The CVs of stance, swing and double support were significantly greater with eyes closed and, with the exception of double support, these differences were greater in the tumor groups. The instability of the trajectories of the center of force was significantly greater in the tumor group, and in the large tumor group the horizontal component of sway movement of the trajectories of the center of force of the foot on the same side as the lesion was greater than that on the intact side with eyes closed. Regarding foot pressure differences between the two feet, the large tumor group had a greater foot pressure for the foot on the same side as the lesion than for the foot on the intact side, especially with eyes closed. No significant difference was found in the small tumor group. Conclusion The presence of acoustic neuroma may cause unstable gait, and steady gait is considerably dependent on visual input. Larger tumors may produce shifts in the bodys center of gravity to the lesioned side during gait, especially under conditions of visual deprivation. These abnormalities may reflect some influences on gait control systems such as phase and muscular tonus control systems.

Influence of nasal obstruction on obstructive sleep apnea.

Nasal obstruction, either partial or complete, may cause snoring and/or obstructive sleep apnea (OSA). However, there is no clear answer to the question, in how many cases nasal airway is a main or combined site of obstruction. Fifty-four OSA cases (47 men and 7 women) were examined by measuring the upper airway pressure gradient while they were asleep, using a multi-sensor pressure transducer. Their average apnea + hypopnea index was 35.6/h and body mass index was 26.5 kg/m2. Our hypothesis was that elevation of the inspiratory negative airway pressure at the epipharynx could indicate the influence of nasal obstruction. Seven cases out of 54 proved to have inspiratory negative pressure more than -3 cmH2O at the epipharynx during sleep. Four cases indicated elevated negative pressure in the lateral position, and 3 cases out of 19 CPAP candidates showed the same elevation in the supine position. In all 7 cases, the main obstructive site was either at the soft palate or the base of the tongue. Although nasal airway is the preferred route of respiration during sleep, nasal obstruction itself cannot be a main factor causing OSA, but a co-factor of OSA during sleep.

Gait instability caused by vestibular disorders - analysis by tactile sensor.

OBJECTIVE To elucidate instability of gait performance in patients with vestibular lesions by the use of a tactile sensors placed under both feet. METHODS Gait analysis was conducted by the use of tactile sensors in 92 patients who had various types of vestibular lesions including vestibular neuritis (VN), acoustic neuroma (AN), and spinocerebellar degeneration (SCD). 26 healthy adults served as a control. Variables were coefficient of variation of stance, swing, and double support durations. Morphological analysis of foot pressure progression during stance was also performed. In addition, differences in each foots integrated foot pressure in a gait test were measured, especially in cases with unilateral vestibular lesions. All data was comparatively analyzed between each pathological group and control group. A comparative study between intact side foot and lesion side foot was performed in those unilateral vestibular disorder cases as well. RESULTS Those gait phase related variables were significantly greater in the pathologic group than in the control group, especially under gait with eyes closed. Morphological irregularity of foot pressure progression during stance was shown in cases with VN and SCD and was greatest in SCD cases. As for integrated foot pressure, in most cases with VN, it has become greater in the lesion side foot, suggesting that body center of gravity could shift toward the lesion side during gait. CONCLUSIONS Gait analysis by the use of tactile sensors could provide additional important information regarding vestibular patho-physiology in patients with vestibular system disorders. Accordingly, gait performance tests should also be taken into consideration as a vestibular function test for patients with vertigo.