<p>Skin temperature is detected through signals in unmyelinated C-fibers and thin myelinated Aδ-fibers in the peripheral and central nervous system. Disorders in thin nerve fibres are important and not rare but difficult to diagnose by the most common neurophysiological methods. In this pilot study different methods for quantitative sensory testing, QST, were compared to give some ideas about which method could be the most efficient to use in order to point out injuries of the sensory system in clinical practice. The comparison was made between Békésy (separate warmand cold thresholds) and Marstock test (combined warm and cold thresholds). The study also included the test persons estimations of the difficulty to perform the tests.</p><p>The study showed that there was no practical difference between the tests and that the test persons estimations did not show any indications that the methods differed in rating of difficulty. Our study did not give reason to stop measuring warm and cold detection thresholds separately, which is the international standard and have some theoretical advantages. We also compared detection thresholds for hand and foot, warmth and cold and for both slow and fast temperature changes to enlighten factors that could affect our measuring data.</p>

Generalised polyneuropathy (PNP) is a common cause to neurological impairment, and may be an early symptom of a severe systemic disease. One such illness is hereditary transthyretin (TTR) amyloidosis (ATTR), a progressive fatal disorder caused by a mutation on the TTR gene. More than 100 such mutations have been found worldwide, of which Val30Met is the most common neuropathic variant with initial clinical manifestations indicating small fiber impairment. Differences in onset age, penetrance and phenotypes are present between endemic areas. Liver transplantation generally slows the progress of the symptom development, especially in patients with short disease duration. Ongoing research has also shown promising results with drug interventions. In any event, early diagnosis of PNP onset in ATTR patients is crucial to ensure early therapeutic interventions. Nerve conduction studies (NCS) and electromyography (EMG) provide the basis for evaluation of the functional state of the thick myelinated nerve fibres in patients with symptoms of PNP, but no such quantitative methods are available for the thin myelinated or unmyelinated fibers. Instead, a psychophysical method with thermal quantitative sensory testing (QST) can provide indirect information about the overall function in the afferent small fiber systems. The purpose of thesis was to evaluate the applicability of QST by the Method-of-limits (MLI) for early detection of PNP in Swedish ATTR patients with the Val30Met mutation. In healthy subjects the repeatability of the MLI was assessed, and reference values for thermal perception thresholds (TPT) in several body regions were determined. No significant differences in TPT or pain thresholds were found at repeated testing with MLI, indicating that the MLI is a reliable method. However, the results show that the arrangement of the testing order is of importance, as cold (CT) and warm (WT) perception thresholds were significantly elevated when tested after thermal pain assessments, instead of before. I general, the TPT was more elevated at lower parts of the body compared to the upper part, and with higher WT than CT, fully in accordance with the underlying anatomical and physiological prerequisites for QST. In biopsy verified ATTR patients lacking EMG and NCS abnormalities, significantly elevated TPT were found compared to controls. Furthermore, significantly more increased TPT were observed in patients with an early onset of the disease, compared those with a late onset. Finally, a combined detailed evaluation of QST and heart rate variability (HRV) analyses demonstrated correlations between QST and HRV abnormalities in patients with late onset, but not in those with early onset. The present thesis emphasizes the importance of incorporating QST early in the clinical evaluation of ATTR patients with a Val30Met mutation and with symptoms of thin fiber PNP. This is particularly indicated when patients report symptoms, or show signs, of neuropathic small fiber affection, but simultaneously exhibit normal EMG and NCS findings. The results furthermore underline the importance of performing both QST and HRV for a complete evaluation of both the thin somatic and autonomic nerve fibers, as both types of nerves may be affected early in the ATTR disease.

Skin temperature is detected through signals in unmyelinated C-fibers and thin myelinated Aδ-fibers in the peripheral and central nervous system. Disorders in thin nerve fibres are important and not rare but difficult to diagnose by the most common neurophysiological methods. In this pilot study different methods for quantitative sensory testing, QST, were compared to give some ideas about which method could be the most efficient to use in order to point out injuries of the sensory system in clinical practice. The comparison was made between Békésy (separate warmand cold thresholds) and Marstock test (combined warm and cold thresholds). The study also included the test persons estimations of the difficulty to perform the tests. The study showed that there was no practical difference between the tests and that the test persons estimations did not show any indications that the methods differed in rating of difficulty. Our study did not give reason to stop measuring warm and cold detection thresholds separately, which is the international standard and have some theoretical advantages. We also compared detection thresholds for hand and foot, warmth and cold and for both slow and fast temperature changes to enlighten factors that could affect our measuring data.

The need for hearing health care services across the world far outweighs the capacity to deliver these services with the present shortage of hearing health care personnel. Automated test procedures coupled with telemedicine may assist in extending services. Automated threshold audiometry has existed for many decades; however, there has been a lack of systematic evidence supporting its clinical use. The aim of this study was to systematically review the current body of peer-reviewed publications on the validity (test-retest reliability and accuracy) of automated threshold audiometry. A meta-analysis was thereafter conducted to combine and quantify the results of individual reports so that an overall assessment of validity based on existing evidence could be made for automated threshold audiometry. A systematic literature review and meta-analysis was conducted using peerreviewed publications. A multifaceted approach, covering several databases and employing different search strategies, was utilized to ensure comprehensive coverage and crosschecking of search findings. Publications were obtained using the following three databases: Medline, SCOPUS and PubMed, and by inspecting the reference list of relevant reports. Reports were selected based according to inclusion and an exclusion criterion, thereafter data extraction was conducted. Subsequently, the meta-analysis combined and quantified data to determine the validity of automated threshold audiometry. In total, 29 articles met the inclusion criteria. The outcomes from these studies indicated that two types of automated threshold testing procedures have been utilized, the ‘method of limits’ and ‘method of adjustments’. Reported findings suggest accurate and reliable thresholds when utilizing automated audiometry. Most of the reports included data on adult populations using air conduction testing, limited data on children, bone conduction testing and the effects of hearing status on automated threshold testing were however reported. The meta-analysis revealed that test-retest reliability for automated threshold audiometry was within typical testretest reliability for manual audiometry. Furthermore, the meta-analysis showed comparable overall average differences between manual and automated air conduction audiometry (0.4 dB, 6.1 SD) compared to test-retest differences for manual (1.3 dB, 6.1 SD) and automated (0.3 dB, 6.9 SD) air conduction audiometry. Overall, no significant differences (p>0.01; Summarized Data ANOVA) were obtained in any of the comparisons between test-retest reliability (manual and automated) and accuracy. Current evidence demonstrates that automated threshold audiometry can produce an accurate measure of hearing threshold. The differences between automated and manual audiometry fall within typical test-retest and inter-tester variability. Despite its long history however, validation is still limited for (i) automated bone conduction audiometry; (ii) automated audiometry in children and difficult-to-test populations and; (iii) automated audiometry with different types and degrees of hearing loss. / Dissertation (MCommunication Pathology)--University of Pretoria, 2013. / gm2014 / Speech-Language Pathology and Audiology / unrestricted