OBJECTIVE: To follow the clinical course of patients with the mitochondrial DNA mutation 3243A>G for 3 years. METHODS: Thirty-three adult patients with the 3243A>G mutation entered a 3-year follow-up study. They were clinically evaluated annually, audiometry was performed, and samples were drawn for the analysis of blood chemistry and mutation heteroplasmy in leukocytes. Holter recording was performed three times during the follow-up and echocardiography, neuropsychological assessment, and quantitative EEG and brain imaging conducted at entry and after 3 years. RESULTS: The incidence of new neurologic events was low during the 3-year follow-up. Sensorineural hearing impairment (SNHI) progressed, left ventricular wall thickness increased, mean alpha frequency in the occipital and parietal regions decreased, and the severity of disease index (modified Rankin score) progressed significantly. The rate of SNHI progression correlated with mutation heteroplasmy in muscle. The increase in left ventricular wall thickness was seen almost exclusively in diabetic patients. Seven patients died during the follow-up, and they were generally more severely affected than those who survived. CONCLUSIONS: Significant changes in the severity of disease, sensorineural hearing impairment, left ventricular hypertrophy, and quantitative EEG were seen in adult patients with 3243A>G during the 3-year follow-up.
Comment In: Neurology. 2007 Jan 9;68(2):163-417210904
In the present study, pure-tone audiometry was used in 687 Finnish school children, aged 6-15 years, to determine the prevalence of a 6 kHz acoustic dip and related factors among three age groups. Trained audiometricians tested air conduction thresholds in a sound-proof room. A total of 57 children (8.3%) had a clear-cut dip of at least 20 dB at 6 kHz. This dip was more pronounced in older children and in boys. A thorough case history was obtained by questionnaire, with logistic regression analysis showing that low birth weight (
Bladder exstrophy is a congenital malformation of the bladder and urethra. The genetic basis of this malformation is unknown however it is well known that chromosomal aberrations can lead to defects in organ development. A few bladder exstrophy patients have been described to carry chromosomal aberrations. Chromosomal rearrangements of 22q11.2 are implicated in several genomic disorders i.e. DiGeorge/velocardiofacial- and cat-eye syndrome. Deletions within this chromosomal region are relatively common while duplications of 22q11.2 are much less frequently observed. An increasing number of reports of microduplications of this region describe a highly variable phenotype. We have performed array-CGH analysis of 36 Swedish bladder exstrophy patients. The analysis revealed a similar and approximately 3 Mb duplication, consistent with the recently described 22q11.2 microduplication syndrome, in two unrelated cases with bladder exstrophy and hearing impairment. This finding was confirmed by multiplex ligation-dependent probe amplification (MLPA) and FISH analysis. Subsequent MLPA analysis of this chromosomal region in 33 bladder exstrophy patients did not reveal any deletion/duplication within this region. MLPA analysis of 171 anonymous control individuals revealed one individual carrying this microduplication. This is the first report of 22q11.2 microduplication associated with bladder exstrophy and hearing impairment. Furthermore the finding of one carrier among a cohort of normal controls further highlights the variable phenotype linked to this microduplication syndrome.
The A1555G mutation of the mtDNA is associated with both aminoglycoside-induced and non-syndromic hearing loss. The A1555G is relatively frequent in the Spanish and some Asian populations, but has only been reported rarely in other populations, possibly because of ascertainment bias. We studied 85 Danish patients with varying degrees of hearing impairment and found two patients with the A1555G mutation (2.4%). Neither had received aminoglycosides. Our study indicates that the mutation might not be uncommon in Danish patients with hearing impairment.
It is suggested that, within the same energy level, an impulse noise is more hazardous to hearing than a permanent noise. To justify this hypothesis, a study was performed with groups of wood-cutters and shipyard workers to investigate different characteristics of noise load (noise levels, noise impulsivity from the outside and under the ear-flaps, noise emission levels with regard to the length of work and using ear-flaps), and hearing losses (both real and forecasted on the Robinson model). To avoid individual factors, a computerized assessment of 38 pairs of workers from both teams was performed (with regard to similar noise emission levels, diastolic pressures, smoking habits, their military service backgrounds as to the service in heavy artillery units, absence of otic diseases, low consumption of salicylates). The results showed that, within the same energy level, the noise in the shipyard was three times as impulsive and more otic disorders inducing than the noise in the wood-cutters' working conditions.
Acoustic neuroma (AN) is a tumor of the 8th cranial nerve. The goal of this study was to find the incidence of AN in Iceland from 1979 - 2009 as well as investigate other epidemiological factors.
The group of patients with the AN diagnosis was gathered retrospectively through medical records. We looked at several epidemiological factors including age and symptoms at diagnosis, and the treatment chosen for each individual.
The incidence rate of AN in Iceland is 1.24/100,000. About 10% of diagnosed tumors were found incidentally. Most of those were found in the last 10 years of the investigation and in that period fewer large and giant tumors at diagnosis. Present complaints of patients at diagnosis were hearing loss (69%), dysequilibrium/dizziness (47%) and tinnitus (43%). Treatments were surgery (n=47), observation (n=30) and gamma knife radiosurgery (n=16). We had information concerning postoperative hearing loss and facial paralysis in 39 patients who underwent surgery. Loss of hearing postoperatively occurred in 69% (n=27) and 44% (n=17) had facial paralysis. For an average of 3.5 years, 17% of tumors followed by imaging grew.
The incidence of AN is similar to that in Europe and is increasing. More tumors are found incidentally. Small tumors can be followed by regular imaging, at least for the short term. Larger tumors are treated by surgery or gamma knife radiosurgery. A high percentage of patients receiving surgery lost their hearing postoperatively.
A series of 40 patients with acoustic neuromas were operated on using the suboccipital or the translabyrinthine approach. Some patients were operated on using both routes. The series extends back to 1977 and contain predominantly large tumours. There was no mortality in the translabyrinthine series of 14 patients. In the suboccipitally treated series of 29 patient, 3 were previously treated using translabyrinthine approach. In this series there was one death directly due to sequelae of neuroma extirpation and in another, additional causes were present. Preoperative facial pareses were frequent. There were several additional pareses in the translabyrinthine series and also several additional in the suboccipital series. Facial pareses were operated on by a plastic surgeon and they did not markedly detract from working capacity. Only 2 patients in the total series had small tumours and useful preoperative hearing. Cochlear function was preserved in them.
The results from the Danish model of acoustic neuroma surgery are presented. In the period from 1976 to 1985, 300 patients with acoustic neuromas were operated upon using the translabyrinthine procedure. Only one small intrameatal tumour was encountered; 96 tumours were medium sized and 203 were larger than 25 mm. Of these 118 measured more than 40 mm. Mortality rate was 2%, CSF leaks occurred in 11%, and had to be closed surgically in 5%. Facial nerve function was postoperatively normal in 66%, slightly reduced in 17%, moderately reduced in 8% and abolished in 9%. Reconstruction, most often as a XII-VII anastomosis, was performed in only 6% of the patients. Cerebellar symptoms, which occurred in 45% preoperatively were present in only 7% after surgery. The preoperative hearing in both the tumour and non-tumour ear was analysed in 72 patients with tumours smaller than 2 cm. In the tumour ear, only four patients had a PTA of 0-20 dB and SDS of 81-100%; eight patients had a PTA of 0-40 dB and SDS of 61-100%; 14 had a PTA of 0-50 dB and SDS of 51-100%. This means that only a maximum of 5% of the patients, using the broadest criteria, could be candidates for hearing-conserving surgery. In all these patients the contralateral ear had hearing within normal limits (PTA 0-20 dB and SDS 95-100%). Since preservation of hearing would be achieved in only half of those subjected to suboccipital removal and since the hearing retained in patients with successful operations generally is poorer than the preoperative level, the number of patients obtaining serviceable hearing is so modest that preservation of hearing cannot be considered a valid argument in favour of suboccipital tumour removal. From a statistical point of view the risk of losing hearing in the opposite ear after tumour removal is negligible. The general morbidity after suboccipital surgery is higher than after translabyrinthine surgery, and hearing loss must be listed low among the other sequelae after tumour removal.