Hyperacusis in children: A scoping review

© 2020 The Author(s). Background: Hyperacusis is a chronic condition commonly defined as a lowered tolerance or increased sensitivity to everyday environmental sounds. It has been viewed as a paediatric disorder which can cause significant impairment to a child's normal functioning. Although clinical guidance highlights the importance of identifying whether the child has intolerance to loud sounds and managing this appropriately, there are currently no assessment or treatment methods that have been designed and tested for use with children with hyperacusis. A review is therefore indicated to consider the profile of children with hyperacusis as a basis for future research into their assessment and treatment. Method: A scoping review methodology was followed with literature searches conducted in Embase, PsychINFO, PubMed CENTRAL, Scopus, Web of Science and Google Scholar. Research articles were included if they reported on research studies describing children diagnosed with hyperacusis, providing clinical profile information, and/or reporting on an assessment or management method for children with a primary complaint of hyperacusis. Data were charted on Excel and verified by a second researcher. Twenty-one research articles were included. Results: Children with hyperacusis are typically described in terms of age at presentation, troublesome sounds, physical sensation, behavioural reactions, coping strategies, comorbid conditions and impact on daily life. Methods of assessing the children include semi-structured interviews, questionnaires, neurological assessment, observation and uncomfortable loudness levels. Management methods include psychological therapy, sound therapy, tinnitus retraining therapy, medication and neuro-rehabilitation. Conclusion: The information we catalogued on various elements of clinical profile, assessment and management can serve as a stepping stone in future research developing questionnaires for clinical measurement of the impact of hyperacusis on children, and the measurement of treatment related change in clinic and in trials. Positive outcomes were noted by the authors following all of the above treatments; future research must compare these and specify the parameters for optimal results

Role of Pyruvate Dehydrogenase Kinase 4 in Regulation of Blood Glucose Levels

In the well-fed state a relatively high activity of the pyruvate dehydrogenase complex (PDC) reduces blood glucose levels by directing the carbon of pyruvate into the citric acid cycle. In the fasted state a relatively low activity of the PDC helps maintain blood glucose levels by conserving pyruvate and other three carbon compounds for gluconeogenesis. The relative activities of the pyruvate dehydrogenase kinases (PDKs) and the opposing pyruvate dehydrogenase phosphatases determine the activity of PDC in the fed and fasted states. Up regulation of PDK4 is largely responsible for inactivation of PDC in the fasted state. PDK4 knockout mice have lower fasting blood glucose levels than wild type mice, proving that up regulation of PDK4 is important for normal glucose homeostasis. In type 2 diabetes, up regulation of PDK4 also inactivates PDC, which promotes gluconeogenesis and thereby contributes to the hyperglycemia characteristic of this disease. When fed a high fat diet, wild type mice develop fasting hyperglycemia but PDK4 knockout mice remain euglycemic, proving that up regulation of PDK4 contributes to hyperglycemia in diabetes. These finding suggest PDK4 inhibitors might prove useful in the treatment of type 2 diabetes

Suppression head impulse test in children—experiences in a tertiary paediatric vestibular centre

The suppression head impulse paradigm (SHIMP) involves suppression of the vestibulo-ocular reflex (VOR) and anticompensatory saccades generated thereof. SHIMP is gaining importance to understand vestibular compensation with its different parameters (VOR gain/peak saccadic velocity PSV/latency of saccades). SHIMP studies are emerging in adults, but pediatric studies have hardly been performed. This study is a retrospective case note audit over a period of 2 months in a tertiary pediatric vestibular center in the United Kingdom to investigate whether SHIMP is safe/robust to be used in children conforming to existing standards/norms in normal children and whether it yields any meaningful inferences in pediatric vestibular hypofunction. This is the largest pediatric SHIMP study to date. A total of 44 referred children (6–18 years, female children>male children) with a range of complaints from dizziness, imbalance, motor incoordination, postural instability, and hearing loss were included, and their SHIMP parameters were measured. All children underwent comprehensive functional/objective audiovestibular assessments. Two groups were defined—Group A with normal vestibular function and Group B with abnormal vestibular function. The normal population showed an average SHIMP VOR gain of 0.98+/−0.08 and latency of overt saccades at 215.68+/–46.16 milliseconds agreeing with published evidence. The PSV of overt saccades was 315.39+/−56.30/s, and there was a gain asymmetry of 7.42+/−4.68 between the sides. Statistically significant differences with moderate/large effect sizes were observed between the groups in terms of VOR gain and PSV but not in saccade latencies. Covert saccades were rare in SHIMP, while overt saccades were observed in 100% of children. VOR gain difference between the head impulse paradigm (HIMP) and the SHIMP was significant as well. We observed statistically significant differences in side asymmetry of VOR gain between the groups. Furthermore, we identified a group of children with cerebellar lesions where overt saccades in SHIMP were rather low in number. Further research is recommended to investigate pediatric PSV, asymmetry, and inability to generate overt saccades that may suggest useful means to assess compensation and central function. We conclude that SHIMP yields valuable information and is a safe, easy to perform, and a reliable test that should be used in children to supplement HIMP