[Subependymoma of the lateral ventricle: a case report].

We report a case of subependymoma of the right lateral ventricle in a 59-year-old man. CT revealed a mass lesion in the right lateral ventricle. No calcification was seen in the tumor, and the right lateral ventricle was dilated dominantly by the tumor. The tumor showed intermediate intensity on T1-weighted MR images and high intensity on T2-weighted MR images. On contrast study, the tumor showed heterogeneous enhancement. We suspected this to be a case of central neurocytoma, and surgical resection was performed. The histological diagnosis was subependymoma, but we considered it difficult to differentiate from astrocytoma, central neurocytoma, and ependymoma.

Esophageal pressure and apnea hypopnea index in sleep-disordered breathing.

Severity of negative esophageal pressure (Pes) and apnea hypopnea index (AHI) were investigated in six cases of upper airway resistance syndrome (UARS) and 11 cases of obstructive sleep apnea syndrome (OSAS). The severity of negative Pes was represented by the highest peak (Pes Max) and the number of increased episodes (more than 13.5 cmH2O) per h (NPesI13.5). There was no significant correlation between Pes indices and AHI. Pes Max and NPesI13.5 were not different among severe OSAS (AHI > 30), mild OSAS (AHI < 30) and UARS. Apnea hypopnea index failed to represent the severity of negative Pes, which is an important aspect of the pathophysiology of sleep-disordered breathing.

The relationship between esophageal pressure and apnea hypopnea index in obstructive sleep apnea-hypopnea syndrome.

Severity of negative esophageal pressure (Pes) and apnea hypopnea index (AHI) were investigated in 34 patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). The OSAHS patients were diagnostically classified as having obstructive sleep apnea syndrome (OSAS) or upper airway resistance syndrome (UARS). Diagnosis of OSAS was based on an AHI of more than 5, and that of UARS on an AHI of less than 5, EEG arousals which were associated with apnea, hypopnea and/or respiratory effort occurring more than 10 times per hour, and daytime sleepiness. Negative Pes was represented by the greatest peak (NPes Max) and the number of increased (more than 13.5 cmH2O) episodes per hour (NPesI13.5). There was no significant correlation between the AHI and Pes indices, but NPes Max and NPesI13.5 showed significant correlation (p<0.01). NPes Max and NPesI13.5 showed no significant differences among the severe OSAS (AHI>50; 8 cases), moderate OSAS (50>AHI>15; 10 cases), mild OSAS (15>AHI>5; 9 cases) and UARS (7 cases) groups. We conclude that AHI does not reflect the severity of the increase in negative Pes, which is an important aspect of the pathophysiology of OSAHS. Assessment of OSAHS based on AHI alone may therefore underestimate the risk of increased negative Pes in cases with reduced AHI.

Frequent breathing-related electroencephalogram arousals in four patients with mild obstructive sleep apneas.

We report cases of four patients with mild obstructive sleep apnea syndrome (OSAS) with frequent breathing-related electroencephalogram (EEG) arousals which led to excessive daytime sleepiness. In spite of a relatively low apnea hypopnea index (AHI), sleep was disrupted by frequent EEG arousals associated with respiratory effort as observed in upper airway resistance syndrome. The effects of sleep stage and sleep position on EEG arousals were also investigated. We consider that AHI alone is not a sufficient index to assess severity of OSAS, and it is very important to examine microarousals by the alteration of esophageal pressure in addition to the effect of sleep position.

Clinical characteristics of upper airway resistance syndrome.

Polysomnographic findings and clinical symptoms were investigated in 14 cases of upper airway resistance syndrome. The mean scores of the Epworth sleepiness scale and self-rating depression scale in eight cases were 13.5 and 38.6, respectively. The mean sleep latency of the multiple sleep latency test in four cases was 10.2 min. Seven cases were treated with continuous positive airway pressure (CPAP), and one with hormone replacement therapy. The most common symptom was daytime sleepiness. Five cases had hypertension. CPAP reduced increasing negative esophageal pressure (Pes) and frequency of EEG arousals, and improved hypertension in one case. Hormone replacement therapy ameliorated increasing negative Pes and clinical symptoms.

Alteration of esophageal pressure in sleep-disordered breathing.

We investigated the alteration of esophageal pressure (Pes) in 10 patients with upper-airway sleep-disordered breathing (UASDB) and the relationship among Pes, breathing patterns and EEG arousals. Increased negative Pes without apnea or hypopnea, appeared not only in upper airway resistance syndrome but also in obstructive sleep apnea syndrome. This phenomenon produced frequent EEG microarousals leading to sleep fragmentation and daytime sleepiness. Moreover, increased negative Pes occasionally continued for more than 20 min without an EEG arousal, which might be considered to be one of the factors to cause complications of UASDB.

Two cases of sleep-disordered breathing in climacteric.

Two cases of sleep disordered-breathing in climacteric were reported. Polysomnography including esophageal pressure (Pes) measurement was performed. Case 1 was diagnosed as upper airway resistance syndrome. Case 2 was diagnosed as obstructive sleep apnea syndrome, while many episodes of upper airway resistance also existed. Hormone replacement therapy improved clinical symptoms, and in case 1, Pes nadir was improved but incidence of arousals which was induced by breathing disturbances was not significantly changed. Sleep disordered-breathing should be suspected as a cause of sleep disorder even in females, especially in climacteric age. Pes measurement and evaluation of arousals is required. Hormone replacement therapy may release the upper airway resistance.