George S. Korres

Diagnosis of Single- or Multiple-Canal Benign Paroxysmal Positional Vertigo according to the Type of Nystagmus.

Benign paroxysmal positional vertigo (BPPV) is a common peripheral vestibular disorder encountered in primary care and specialist otolaryngology and neurology clinics. It is associated with a characteristic paroxysmal positional nystagmus, which can be elicited with specific diagnostic positional maneuvers, such as the Dix-Hallpike test and the supine roll test. Current clinical research focused on diagnosing and treating various types of BPPV, according to the semicircular canal involved and according to the implicated pathogenetic mechanism. Cases of multiple-canal BPPV have been specifically investigated because until recently these were resistant to treatment with standard canalith repositioning procedures. Probably, the most significant factor in diagnosis of the type of BPPV is observation of the provoked nystagmus, during the diagnostic positional maneuvers. We describe in detail the various types of nystagmus, according to the canals involved, which are the keypoint to accurate diagnosis.

Treatment of the horizontal semicircular canal canalithiasis: pros and cons of the repositioning maneuvers in a clinical study and critical review of the literature.

Objective: Several repositioning maneuvers have been proposed for the treatment of benign paroxysmal positional vertigo (BPPV) due to canalithiasis of the horizontal semicircular canal (HSC). However, comparisons between these canalith repositioning procedures as well as a generally accepted algorithm for the management of HSC canalithiasis are currently lacking. The aim of this study was to compare the efficacy of 3 different treatment proposals and review the relevant literature. Study Design: Prospective clinical study. Setting: Tertiary neurotology department. Patients: Sixty patients diagnosed with HSC canalithiasis. Interventions: A single application of Balohs maneuver (n = 13), Vannucchis forced prolonged position (n = 29), or Asprella-Gufoni maneuver (n = 18). Main Outcome Measures: Bilateral geotropic nystagmus. Results: The first application of the Balohs maneuver seemed to be significantly less effective than both Vannucchis forced prolonged position (p = 0.035) and the Asprella-Gufoni maneuver (p = 0.006). No significant difference was detected in the efficiency of Vannucchis forced prolonged position and the Asprella-Gufoni maneuver for this population (p = 0.4). Conclusion: The Asprella-Gufoni maneuver and Vannucchis forced prolonged position both seem to be significantly more effective than the Balohs maneuver in the treatment of HSC canalithiasis. The important pros of the Asprella-Gufoni maneuver versus Vannucchis forced prolonged position are patients convenience and maximal use of gravitational and angular acceleration forces. Controlled clinical studies are needed to conclude to an evidence-based proposal for the therapeutical steps that should be followed after the diagnosis of HSC canalithiasis.

Apogeotropic variant of lateral semicircular canal benign paroxysmal positional vertigo: is there a correlation between clinical findings, underlying pathophysiologic mechanisms and the effectiveness of repositioning maneuvers?

Objective The apogeotropic variant of horizontal semicircular canal (h-SCC) benign paroxysmal positional vertigo (BPPV) is attributed to canalithiasis of the anterior arm or cupulolithiasis. This study is an attempt to distinguish the most effective maneuvers for each case, by investigating any correlation, between the clinical findings or the treatment options and the possible location of the displaced debris. Data Sources A review of the literature (1990–2012) was conducted via the PubMed database with the search terms “apogeotropic nystagmus and benign paroxysmal positional vertigo.” Study Selection Articles on central nervous system lesions were excluded. Data Extraction The studies included in the analysis provided detailed diagnostic and therapeutic protocols, supported by the resolution of the signs and symptoms through repositioning maneuvers. Data Synthesis Descriptive statistics were used to summarize the findings. Intergroup and intragroup comparisons were performed through Pearson’s &khgr;2 or Fischer’s exact test. Conclusion Protocols vary considerably among studies. Nystagmus from seated to supine position is the best studied secondary clinical sign and possibly a clinical indication of cupulolithiasis. In patients with symmetrical responses in the head yaw test, no significant differences can be detected in the occurrence of secondary signs of lateralization compared to patients with asymmetrical responses. The Gufoni maneuver seems to be effective in all pathophysiologic types of apogeotropic h-SCC BPPV. The Barbeque and Vannucchi-Asprella maneuvers mainly target at lithiasis of the anterior ampullary arm. The results of this analysis may imply that different clinical subgroups of h-SCC BPPV may regard to different pathophysiologic and therapeutical mechanisms.

Detection of deafness-causing mutations in the Greek mitochondrial genome

Mitochondrion harbors its own DNA, known as mtDNA, encoding certain essential components of the mitochondrial respiratory chain and protein synthesis apparatus. mtDNA mutations have an impact on cellular ATP production and many of them are undoubtedly a factor that contributes to sensorineural deafness, including both syndromic and non-syndromic forms. Hot spot regions for deafness mutations are the MTRNR1 gene, encoding the 12S rRNA, the MTTS1 gene, encoding the tRNA for Ser(UCN), and the MTTL1 gene, encoding the tRNA for Leu(UUR). We investigated the impact of mtDNA mutations in the Greek hearing impaired population, by testing a cohort of 513 patients suffering from childhood onset prelingual or postlingual, bilateral, sensorineural, syndromic or non-syndromic hearing loss of any degree for six mitochondrial variants previously associated with deafness. Screening involved the MTRNR1 961delT/insC and A1555G mutations, the MTTL1 A3243G mutation, and the MTTS1 A7445G, 7472insC and T7510C mutations. Although two patients were tested positive for the A1555G mutation, we failed to identify any subject carrying the 961delT/insC, A3243G, A7445G, 7472insC, or T7510C mutations. Our findings strongly support our previously raised conclusion that mtDNA mutations are not a major risk factor for sensorineural deafness in the Greek population.

The A1555G mitochondrial DNA mutation in Greek patients with non-syndromic, sensorineural hearing loss

Mitochondrial DNA mutations are undoubtedly a factor that contributes to sensorineural, non-syndromic deafness. One specific mutation, the A1555G, is associated with both aminoglycoside-induced and non-syndromic hearing impairment. The mutation is considered to be the most common of all mitochondrial DNA deafness-causing mutations but its frequency varies between different populations. Here we report on the first large screening of the A1555G mitochondrial DNA mutation in the Greek population. The aim of this study was to determine the frequency of the A1555G mutation in Greek sensorineural, non-syndromic deafness patients, with childhood onset. We screened 478 unrelated Greek patients with hearing loss of any degree and found two individuals harboring the A1555G mutation (0.42%). Both cases had been subjected to aminoglycosides. They were prelingual, familial and homoplasmic for the A1555G mutation. One of the cases was also found heterozygous for the frequent GJB2 35delG mutation, while the other case was negative. The A1555G mutation seems to be less common than in other European populations.

Study of Allergic Rhinitis in Childhood

Allergic rhinitis is common among children and quite often represents a stage of the atopic march. Although sensitization to food and airborne allergens may appear in infancy and early childhood, symptoms of the disease are usually present after age 3. The aim of this study was to determine the most frequent food and indoor and outdoor respiratory allergens involved in allergic rhinitis in children in the region of Piraeus. The study was performed in the outpatient clinic of otolaryngologic allergy of a general hospital. Fifty children (ranged 6–14 ) with symptoms of allergic rhinitis and positive radioallergosorbent test (RAST) for IgE antibodies or skin prick tests were included in the study. Thirty six (72%) of the subjects of the study had intermittent allergic rhinitis. The most common aeroallergens determined were grass pollens and Parietaria, whereas egg and milk were the food allergens identified. The detection of indoor and outdoor allergens in the region of Piraeus, based on skin prick tests and RAST tests, showed high incidence of grasses and food allergens, which is similar to other Mediterranean countries.

Are GJB2 mutations an aggravating factor in the phenotypic expression of mitochondrial non-syndromic deafness?

Hearing impairment is a frequent condition, and genes have an important role in its etiology. The majority of hearing loss occurs in non-syndromic form, with deafness being the only clinically recognizable feature. More than 60 nuclear genes or loci have been shown to be involved in non-syndromic hearing loss, but mutations in mitochondrial DNA also cause hearing impairment. Mitochondrial DNA mutations usually lead to progressive hearing loss with an age of onset varying from childhood to early adulthood. It is interesting to note that there is a great variability among phenotypes between individuals harboring the same mitochondrial mutation, even within the same family, and the phenotype may range from profound deafness to completely normal hearing. In the past years, the debate on mitochondrial mutations has been about the penetrance, the tissue specificity and the mechanisms of modifier genes that can modulate the severity of the phenotypic expression of the deafness-associated mitochondrial DNA mutations. Here we summarize evidence regarding modifying genes, and we discuss the effect of the coexistence of mitochondrial and GJB2 mutations in families reported to date.

Homoplasmy of the G7444A mtDNA and heterozygosity of the GJB2 c.35delG mutations in a family with hearing loss

OBJECTIVE Mitochondrial mutations have been shown to be responsible for syndromic as well as non-syndromic hearing loss. The G7444A mitochondrial DNA mutation affects COI/the precursor of tRNA(Ser(UCN)), encoding the first subunit of cytochrome oxidase. Here we report on the first Greek family with the G7444A mitochondrial DNA mutation. METHODS Clinical, cytogenetic, and molecular methods were employed in this study. RESULTS We describe the high variability of phenotypes among three family members harboring the G7444A mutation and also the frequent GJB2 c.35delG mutation of the nuclear genome in heterozygosity. Their phenotypes ranged from normal hearing to deafness, while the proband presented with several other symptoms. CONCLUSIONS The G7444A mitochondrial DNA mutation has been reported in only a few cases worldwide, alone or in cosegregation with other mitochondrial DNA mutations, but to our knowledge, never before in coexistence with the GJB2 c.35delG mutation.

Transiently Evoked Otoacoustic Emissions in Children with Otitis Media with Effusion

Introduction. Otitis media with effusion is a common pediatric disease whose diagnosis is based on pneumatic otoscopy, pure-tone audiometry, and tympanometry. The aim of this study was to evaluate transiently evoked otoacoustic emissions in the diagnosis of otitis media with effusion as compared to tympanometry. Patients and Methods. 38 children with bilateral otitis media with effusion were studied. 40 normal children of similar age and sex were used as controls. All subjects underwent pneumatic otoscopy, standard pure-tone audiometry, tympanometry, and transiently evoked otoacoustic emissions. Results. In the group of children with bilateral otitis media, transiently evoked otoacoustic emissions were absent in 51 ears (67%). In the remaining 25 ears (33%) the mean emission amplitude was reduced, as compared to the mean value of the control group. Conclusions. Transiently evoked otoacoustic emissions should be included in the diagnostic workup of otitis media with effusion because it is a fast, reliable, and objective test. Transiently evoked otoacoustic emissions should always be used in conjunction with tympanometry, because a more meaningful interpretation of transiently evoked otoacoustic emissions measures is possible.