Federica Bressi

Obstructive Sleep Apnea Syndrome: From Phenotype to Genetic Basis

Obstructive sleep apnea syndrome (OSAS) is a complex chronic clinical syndrome, characterized by snoring, periodic apnea, hypoxemia during sleep, and daytime hypersomnolence. It affects 4-5% of the general population. Racial studies and chromosomal mapping, familial studies and twin studies have provided evidence for the possible link between the OSAS and genetic factors and also most of the risk factors involved in the pathogenesis of OSAS are largely genetically determined. A percentage of 35-40% of its variance can be attributed to genetic factors. It is likely that genetic factors associated with craniofacial structure, body fat distribution and neural control of the upper airway muscles interact to produce the OSAS phenotype. Although the role of specific genes that influence the development of OSAS has not yet been identified, current researches, especially in animal model, suggest that several genetic systems may be important. In this chapter, we will first define the OSAS phenotype, the pathogenesis and the risk factors involved in the OSAS that may be inherited, then, we will review the current progress in the genetics of OSAS and suggest a few future perspectives in the development of therapeutic agents for this complex disease entity.

Is obstructive sleep apnea syndrome a risk factor for auditory pathway

PurposeThe transduction mechanism of the inner ear and the transmission of nerve impulses along the auditory way are highly dependent upon the cochlear oxygen supply. Several studies have considered the possibility that obstructive sleep apnea–hypopneas during sleep can interfere with these processes, and the results are not uniform. The aim of the study is to evaluate the auditory function in adult patients affected by severe obstructive sleep apnea syndrome (OSAS).MethodsThirty-nine patients in this study were included and divided in OSAS group, with severe OSAS (Apnea–Hypopnea Index, AHI > 30), and control group with snoring without OSAS (AHI < 5). Each patient was subjected to pure-tone audiogram (PTA), otoacoustic emission (OAE), and brainstem auditory evoked potentials.ResultsThe OSAS group showed a PTA significantly higher than the control group (14.23 ± 6.25 vs. 7.45 ± 2.54; p < 0.01), a lower TEOAE reproducibility (0.57 ± 0.10 vs. 0.92 ± 0.10; p < 0.01) such as a lower signal-to-noise 0atio (p < 0,01) and a lower DPOAE amplitude (5.96 ± 6.34; 13.18 ± 2.97; p < 0.01). The mean latencies of waves I, III, and V were prolonged in OSAS group as compared to the healthy people, especially for wave V (p < 0.05). The interpeak latency (IPL) of I–V was significantly higher (p < 0.01) in the OSAS patients (5.84 ± 0.15) as compared to the control group (5.4 ± 0.12), such as IPLs I–III and III–V (p < 0.05).ConclusionsOur data showed an auditory dysfunction in patients affected by severe OSAS, suggesting that severe OSAS could represent a risk factor for auditory pathway.

Facial Nerve Outcome after Vestibular Schwannoma Surgery: Our Experience

In this study we evaluate the postoperative facial nerve function after vestibular schwannoma (VS) surgery and analyze the factors that cause it. We included 97 consecutive patients undergoing surgical excision of sporadic unilateral VS. Patient and tumor characteristics, surgical approaches, facial nerve function, extent of tumor removal, perioperative complications are all analyzed through standardized systems. Four different surgical approaches are used: translabyrinthine, retrolabyrinthine, retrosigmoid, and middle cranial fossa. Anatomic preservation of the facial nerve is achieved in 97% of patients. The incidence of postoperative facial palsy is found to be statistically correlated to tumor size, but not to the surgical approach used and to extent of tumor penetration in the internal auditory canal. A significant improvement of the short-term facial nerve outcome is detected in patients undergone simultaneous intraoperative electromyography (EMG) and pneumatic facial nerve monitoring. Complete tumor excision is achieved in 94% of cases. Complication rates are excellent and no deaths are reported. Short- and long-term facial nerve outcome is good and comparable with those of other series reported in literature. In VS surgery both EMG and pneumatic facial nerve monitors should be simultaneously used. Further investigations are desirable to improve the facial outcome respecting the oncological radicality.

Ventricular Wall Granulations and Draining of Cerebrospinal Fluid in Chronic Giant Hydrocephalus

BACKGROUND In rare cases, adults with normal or almost normal cognition may have giant brain ventricles surrounded by a sliver of brain. Because the usual flow of cerebrospinal fluid (CSF) is interrupted in these individuals, they may develop alternative CSF pathways to preserve brain function. OBJECTIVE To describe novel morphologic autopsy findings in a patient with chronic giant hydrocephalus that suggest the existence of alternative CSF draining pathways. DESIGN Case report. SETTING Autopsy study. PATIENT A 48-year-old man with chronic compensated hydrocephalus associated with a Dandy-Walker malformation. MAIN OUTCOME MEASURE Autopsy findings. RESULTS We observed microscopic structures on the ventricular wall that may facilitate CSF resorption. Their histologic appearance, reminiscent of pacchionian granulations, showed the opposite relation in regard to CSF/blood compartments: whereas the core of a pacchionian granulation contains CSF and the granulation is bathed in blood of the venous sinus, the core of the ventricular granulation in our patient contained venules, with the granulation bathed in ventricular CSF. CONCLUSIONS These previously unreported (to our knowledge) ventricular wall granulations may facilitate draining of CSF into the venous system when CSF outflow from the ventricular system is occluded. The presence of these ventricular structures illustrates biologic adaptation to anomalous conditions and successful compensation.