Identifying parameters of improvement in voice disorders by use of objective measurement techniques
Authors: LOCKHART MYRA S , PATON FIONA , PEARSON LINDSEY 
Published: April 2011

ABSTRACT  For many years the assessment, evaluation, diagnosis and treatment of voice disorders has included objective measurement techniques as well as many subjective assessments of respiratory and vocal function. This study was established to look into objective measurement as a means of monitoring change within various diagnostic groups of dysphonic patients, using two hospital departments in different locations and comparing the results of clinical data from dysphonia assessments and re‐assessments at approximately 6‐week intervals. The data was collated from the caseload of 10 therapists with experience in the management of dysphonia. It was hoped that the analysis would confirm: (1) Patterns of measureable improvements in different parameters for dysphonia of different aetiologies; (2) Outcome measures for the different aetiological groups in terms of laryngeal condition and voice quality, mean numbers of sessions and weeks. The two centres, Law Hospital NHS Trust (LH) and the Victoria Infirmary NHS Trust (VI), operate similar voice assessment clinic and videostroboscopy procedures and are equipped with similar systems of computer‐assisted instrumentation, i.e. ST1 airflow measurement, Visispeech and the portable electrolaryngograph (ELG). A population sample was carried out at each centre to determine normative values for Visispeech and ELG, in recognition of the variation caused by clinical situations, microphones and user technique. No sampling was necessary for the ST1 airflow instrument (Kelman et al., 1975). The samples included 43 female and 47 male subjects (LH) and 62 females and 21 males (VI). The patient sample involved 67 patients at VI and 70 at LH. Patients were grouped according to the laryngeal diagnosis as follows: vocal strain; oedema; vocal nodules; post‐surgical; ventricular folds; psychogenic; bowing; post‐radiotherapy; contact ulcers; and vocal cord palsy. Patients were treated by therapists within their clinical workload, using their treatment of choice and determining the frequency, length and number of sessions according to their usual procedures. No therapy technique was prescribed and no timescale stated. It was felt that if similar objective results were produced at the two centres, the results could be accepted as indicatng the most vital parameters requiring change to facilitate maximal improvement. Objective assessments confirmed similar results between the two centres in the following: (1) Certain diagnostic groups showed the same parameters to be within normal limits at the initial assessment; (2) Specific parameters were identified in certain diagnostic groups as those showing most change towards normal limits; (3) Different diagnostic groups showed different patterns of normality and change. There were also close similarities in the numbers of treatment sessions and total length of care episode. Having identified the parameters of normality and required change for different diagnostic groups, it may follow that targeting these key areas in therapy will result in maximal improvement in laryngeal condition and voice quality, with efficient use of time and resources. This would have important implications in future objective assessments of dysphonia and planning of appropriate therapy.