Speech synthesis technologies for individuals with vocal disabilities: Voice banking and reconstruction

In this invited paper, we overview the clinical applications of speech synthesis technologies and explain a few selected researches. We also introduce the University of Edinburgh’s new project ‘‘Voice Banking and reconstruction’’ for patients with degenerative diseases, such as motor neurone disease and Parkinson’s disease and show how speech synthesis technologies can improve the quality of life for the patients. 1.1. Speech Disorder and Impairment Speech disorders have a variety of causes. The major neurological degenerative diseases resulting in severe speech disorders include Motor Neurone Disease (MND), Parkinson’s, and Multiple Sclerosis; non-progressive conditions resulting in such disorders include Stroke and Cerebral Palsy. Speech impairment may also be caused by conditions such as cancer of the vocal cords, resulting in laryngectomy. MND, also known in the USA as Amyotrophic Lateral Sclerosis (ALS) or Lou Gehrig’s disease, is a debilitating neurological disease that results from the degeneration and death of the large motor neurones in the brain and spinal cord. This causes a worsening muscle weakness that leads to loss of mobility and difficulties with swallowing, breathing and speech production. Approximately 75% of MND patients are unable to speak by the time of their death 1. There are four types of MNDs. Most cases of ALS and Progressive Bulbar Palsy are recorded in over 60’s. Age of onset of Primary Lateral Sclerosis is fifty years. Age of onset of Progressive Muscular Atrophy is usually under fifty years. About 100 new cases of MND are diagnosed in Scotland, U.K. each year.