Speech-based characterization of dopamine replacement therapy in people with Parkinson's disease.

People with Parkinson's (PWP) disease are under constant tension with respect to their dopamine replacement therapy (DRT) regimen. Waiting too long between doses results in more prominent symptoms, loss of motor function, and greater risk of falling per step. Shortened pill cycles can lead to accelerated habituation and faster development of disabling dyskinesias. The Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is the gold standard for monitoring Parkinson's disease progression but requires a neurologist to administer and therefore is not an ideal instrument to continuously evaluate short-term disease fluctuations. We investigated the feasibility of using speech to detect changes in medication states, based on expectations of subtle changes in voice and content related to dopaminergic levels. We calculated acoustic and prosodic features for three speech tasks (picture description, reverse counting, and diadochokinetic rate) for 25 PWP, each evaluated "ON" and "OFF" DRT. Additionally, we generated semantic features for the picture description task. Classification of ON/OFF medication states using features generated from picture description, reverse counting and diadochokinetic rate tasks resulted in cross-validated accuracy rates of 0.89, 0.84, and 0.60, respectively. The most discriminating task was picture description which provided evidence that participants are more likely to use action words in ON than in OFF state. We also found that speech tempo was modified by DRT. Our results suggest that automatic speech assessment can capture changes associated with the DRT cycle. Given the ease of acquiring speech data, this method shows promise to remotely monitor DRT effects.

Multileaf collimation versus conventional shielding blocks: a time and motion study of beam shaping in radiotherapy.

The work processes for the planning and delivery of shaped beams using a Philips multileaf collimator were studied for two treatment techniques and compared to those for conventional shielding blocks. The MLC proved faster in all cases of treatment delivery providing time reductions of 19-48% for parallel opposed beams and 6-44% for conformal isocentric beams. The workload in the mould room and workshop would be reduced if multileaf collimation is used. Time spent manufacturing and mounting blocks (average 2 h 30 min and 37 min, respectively) is eliminated for the techniques studied. The physics process for generating conformal MLC beams proved faster (average 1 h 36 min) than for blocks (average 2 h 30 min); this was not so for parallel opposed beams. Overall the results suggest that using the MLC is a time- and resource-saving alternative to blocks.

The Royal Marsden Hospital pelvic radiotherapy trial: technical aspects and quality assurance.

Planning and quality control procedures are described for a randomised trial designed to measure the effect on normal tissue toxicity of reducing the volume of normal tissue irradiated through the introduction of Beams-Eye-View designed customised blocks. Consideration is given to the accuracy with which blocks can be designed and to the potential application of multi-leaf collimator technology.