Tinnitus, the perception of sound in the absence of an external sound, emerges from a complex interaction between otologic health, general health/disease, and environmental stressors. Most people experience transient tinnitus at some point, but do genes play a role in susceptibility to chronic tinnitus? As expected this is not an easy question to answer given the heterogeneity of tinnitus.
Zika Virus Disease Outbreak and Infant Hearing Loss
On February 1, the World Health Organization declared a Public Health Emergency of International Concern about the recent outbreak of the Zika Virus Disease. Within one week of the WHO’s declaration, the Center for Disease Control issued its highest response (Level 1) activation, due to the growing number of Zika cases recently reported.
Several large-scale studies are consistently pointing toward an association between human immunodeficiency virus (HIV) and hearing loss. Torre and his colleagues have recently reported HIV as a risk factor for hearing loss in children and adults. HIV-infected children have poorer hearing compared to HIV-unexposed but uninfected children as well as those who are perinatally exposed to HIV, but remain uninfected. HIV-infected adults also have poorer hearing compared to HIV-uninfected adults. Further, the magnitude of hearing loss seems to increase with the severity of HIV.
Single-Sided Deafness, Cochlear Implants, and Speech Understanding
Zeitler et al (2015) reported on nine people (ages 12 to 63 years) with single-sided deafness (SSD) and normal hearing in the other ear, all of whom underwent cochlear implantation in the SSD ear. With regard to post-op speech understanding in noise, the authors report “one of our aims was to assess the value of a CI for SSD patients when the listening environment simulated a ‘real world’ situation, that is, listening in a restaurant where the talker was on the side of the CI.
Engdahl et al (2015) examined the correlation between multiple cardiovascular risk factors and hearing loss. The sample of patients included 31,547 subjects from the Nord-Trondelag hearing loss study. Pure-tone air conduction thresholds were obtained at 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz. Subjects ranged in age from 32 to 99 years (mean age = 57 yrs).
The Importance of Frequency Regions for Cochlear Implant Patients
Sladen and Ricketts (2015) report that given current cochlear implant (CI) technology, the majority of post-lingually deafened adults achieve 80 percent word recognition (in quiet) after only six months experience with a CI. In their study, CI users were presented with monaural information and the NH listeners had binaural input. The noisy condition was a 10 dB SNR with six-talker babble. Of note, “the average decrease in performance between quiet and noisy conditions was 13% for the NH group and 20 percent for the CI group.”
Desmond (2015) reports that Meclizine (aka Antivert, Nonine, and Dramamine II) is an antihistamine with antiemetic and anti-cholinergic properties (i.e., anticholinergics tend to block the transmission of acetylcholine in the PNS and CNS). MedicineNet.com reports that “Meclizine is an antihistamine with antiemetic and antispasmodic activity. It suppresses the nervous system by blocking the action of the neurotransmitter acetylcholine.
Murman (2015) reviews cognitive changes associated with normal aging. He states that “there is emerging evidence that healthy lifestyles may decrease the rate of cognitive decline….” Murman notes that in 1910 the average lifespan for a male was 48 years and for female it was 52. In 2010, the lifespan averages are 76 years for men and 81 years for women. Murman divides cognitive ability into multiple domains—attention, memory, executive cognitive function, language and visuo-spatial ability.
Recently, Maducdoc et al (2015) reported on 12 cases of “malignant transformation” from benign to malignant acoustic neuromas. Of note, some 42 percent of neurotologists treat acoustic neuroma with stereotactic radio surgery (SRS). Indeed, 8 of the 12 cases were noted following SRS and microsurgery (MS), while 4 of the 12 transformed after MS only. The authors note that the mechanism that may lead to a malignant transformation seems “more obvious” for SRS, and is less well understood for MS.