The role of intensity upon pitch perception in cochlear implant recipients

OBJECTIVES: Pitch plays a key role in the perception of speech and music, the recognition of a speaker's voice, and in analyzing complex auditory patterns. To date, little consideration has been given to the influence of stimulation level on pitch perception. The aim of this study was to investigate the impact of a sound's intensity on pitch perception in cochlear implant recipients using monopolar stimulation. STUDY DESIGN: Thirteen patients with an average implant use of 4.13 years took part in this study. All patients were implanted with MedEl Combi 40/40+ cochlear implants. METHODS: In the first part of the study, we performed a pitch ranking procedure to confirm that all patients were able to judge pitch changes. Using a visual scale, study participants were then asked to compare the pitch of an intensity-constant reference tone with the pitch of a test tone of varying intensity. RESULTS: Eleven (85%) patients were found to perceive a clear change in pitch with changing stimulus intensity. Statistical analysis showed a strong positive correlation in 10 patients (correlation coefficients between 0.99 and 0.71) and a strong negative correlation in 1 patient (r = -0.92). CONCLUSIONS: The results suggest that a distinct relationship exists between pitch perception and intensity of the stimulus. To date, speech coding strategies do not support these findings. Nevertheless, we believe that for the optimized most natural perception of sounds, especially music, the described particularities of pitch perception need to be respected, and further investigations on this topic are necessary.     

Photoadaptation of vitiliginous skin to targeted ultraviolet B phototherapy

BACKGROUND: Increasing doses of ultraviolet (UV) radiation are tolerated in patients with vitiligo, due to photoadaptation. In this pilot study, five patients with Fitzpatrick skin phototypes IV-VI with vitiligo received six treatments of targeted UVB phototherapy over a 3-week period. METHODS: To investigate photoadaptation, minimal erythema dose (MED) testing was conducted on treated and untreated vitiliginous and normal skin at baseline and after three and six treatments. One patient had unattainable MED values, and was hence excluded. RESULTS: Percent change in MED from before to after all treatments in vitiliginous skin ranged from 0% to 128%, with a mean of 48.8%. CONCLUSION: The pilot phase of this study suggests possible photoadaptation of vitiliginous skin of some patients to targeted UVB phototherapy.     

Tuning the architecture of three-dimensional collagen hydrogels by physiological macromolecular crowding

Macromolecular crowding is an optimal physiological feature in intracellular and extracellular spaces, and results from a variety of macromolecules occupying space and contributing to a fractional volume occupancy. Here, we show that soft collagen hydrogels assembled in nature-inspired crowded conditions feature enhanced biophysical properties. We demonstrate that crowding tunes the rate of collagen nucleation and fiber growth, affecting fiber diameter and organization. Adjustments of crowding levels during collagen assembly tune the gel pore size, protein permeability, transparency and resistance to enzymatic degradation. Furthermore, gels assembled in crowded conditions are twice as resistant to mechanical stress as the controls, inducing a 70% boost of proliferation of stem cells cultured on tuned hydrogels. Emulating the crowdedness of interstitial fluids therefore represents a way to optimize the properties of soft collagen gels, with promising applications in soft biomaterials design.     

Immunoperoxidase examination of cutaneous infiltrates of mycosis fungoides and large-plaque atrophic parapsoriasis with OKT10

A monoclonal antibody (OKT10), which was developed recently, reacts with pro-thymocytes, T cell acute lymphoblastic leukemia (ALL) cells, cells in normal bone marrow (including plasma cells), and activated T cells. Tissues from patients with cutaneous T cell lymphoma were studied for the presence of OKT10-reactive cells with the use of an indirect immunoperoxidase technic. OKT10-reactive cells were identified in three of eight cases of mycosis fungoides, one of two cases of Sézary syndrome, with an equivocal reaction in one of ten cases of large-plaque parapsoriasis and in one of seven positive patch tests (allergic contact dermatitis). The biologic and possible clinical implications are discussed.     

Intracochlear position of cochlear implant electrodes

The insertion of cochlear implant electrodes in human temporal bones may be associated with the destruction of structures within the cochlea. The aim of this study was to measure such insertional trauma by means of histologic processing of implanted human temporal bones following implantation of a Combi 40/40+ electrode array (Med-El, Innsbruck). We implanted 6 human temporal bones with original electrodes (3 with Combi 40 and 3 with Combi 40+). In 4 bones Healon was used for electrode insertion. The histological investigation was performed after radiographic evaluation of the position of the electrode. For the histological procedure we used a technique which keeps the electrodes in position within the cochlea. In these slides we could clearly identify the electrodes in the tympanic scale. When inserted properly (point of first resistance) no trauma occurred in the basal portion of the cochlea and minimal trauma in the middle portion of the cochlea.     

Speech perception with a cochlear implant used in conjunction with a hearing aid in the opposite ear

The aim of this study was to determine the improvement in speech recognition provided by a cochlear implant (CI) in conjunction with a hearing aid (HA) in the opposite ear. The study was a retrospective cohort study in the context of a university teaching hospital CI programme. Seven CI patients who still use their HA in the opposite ear were tested. The scores with the CI alone and the CI in conjunction with an HA were evaluated by using three speech perception tests in quiet (Freiburger Numbers, Freiburger Monosyllables, and Innsbrucker Sentence Test). In the majority of tests and subjects, the CI alone performed better than the HA alone, and the bimodal (CI+HA) condition was superior to the CI alone. On the sentence test, the patients as a group improved from 47-96% (mean: 79%; CI alone) to 50-100% (mean: 88.1%; CI+HA, pv<0.05). With the more difficult monosyllable test, the scores improved from 15-52% (mean: 37.2%; CI alone) to 15-82% (mean: 48.7%; CI+ HA, p<0.05). On the numbers test, scores increased from 65-98% (mean: 83%; CI alone) to 75-98% (mean: 88.7%; CI+ HA, p<0.05). All patients in this study were implanted in the poorer ear. The results of the present study suggest the advantage of CI usage in conjunction with an HA in the opposite ear.     

Staining of melanocytic neoplasms by melanoma antigen recognized by T cells

We stained benign melanocytic nevi and malignant melanoma with antibodies to melanoma antigen recognized by T cells (Mart-1) to determine if this was useful in differentiating benign from malignant melanocytic neoplasms. Forty-five primary malignant melanomas and 71 benign melanocytic nevi were stained with antibodies to Mart-1. Two cases of malignant melanoma metastatic to lymph node and three cutaneous metastases of malignant melanoma were also stained. The degree of staining was graded into diffuse positive staining, focal positive staining, and negative staining. Thirty-six of 45 primary malignant melanomas stained diffusely positive with antibodies to Mart-1. This included three of five desmoplastic malignant melanomas that showed positive staining. Four melanomas showed faint or focal positive staining. One of two metastases to lymph node showed strong positive staining and one showed no staining. All three cutaneous metastases showed diffuse positive staining. Sixty-one of 71 melanocytic nevi showed no staining or faint staining with antibodies to Mart-1. Ten of 71 melanocytic nevi showed strong positive staining. The majority of these were congenital nevi. Staining with antibodies to Mart-1 antigen was a useful marker of malignant melanoma. However, staining may also be seen in benign melanocytic neoplasms. The presence or absence of staining for Mart-1 antigen cannot be used to differentiate benign melanocytic nevi from malignant melanocytic tumors.