H – I – L – M – N – O
Hallucination – symptom that can be produced by disease or medications, which makes a person believe they are seeing, hearing or feeling things that are not really there – usually without awareness that the sensations are not real.
Hoehn & Yahr scale – system used to rate PD as one of five stages – stage 0 means no symptoms, and stage 5 means the most severe disease stage.
Hypomimia – reduced facial expression, caused by poor action of the face muscles in PD.
Hypophonia – abnormally quiet/whispering speech.
Hyposmia – reduced sense of smell.
Insomnia – inability to sleep.
Lesioning – surgical method used to destroy specific overactive parts of the brain that cause symptoms in PD.
Levodopa – most commonly used medication for the treatment of PD – the ‘gold standard’. After administration, levodopa is converted into dopamine, and is able to raise the levels of dopamine in the brain. It produces effective control of PD symptoms, although its long-term use is associated with complications such as fluctuations and dyskinesias.
MAO-B – abbreviation for monoamine oxidase B, an enzyme that breaks down dopamine in the brain.
MAO-B inhibitors – class of medications that are used to treat the symptoms of early PD, as well as to treat motor fluctuations in more advanced disease. They work by stopping dopamine being broken down by MAO-B in the brain.
Micrographia – very small handwriting.
Motor – term used to refer to movement.
Motor fluctuations – switches between good and bad movement control with levodopa treatment. People may begin to experience motor fluctuations with levodopa treatment when they have had PD for a number of years.
MRI scan – magnetic resonance imaging (MRI) is a scan that uses radio waves to generate an image of body tissues. It is especially useful for examining the nervous system, muscles and bones.
Multiple system atrophy (MSA) – form of parkinsonism that is difficult to distinguish from PD, although poor balance and low blood pressure on standing are the main problems in MSA. It does not typically respond to standard PD treatments.
Nausea – feeling sick/queasy.
Nerve cell transplantation – surgical technique that is being investigated for use in PD. It involves implanting new dopamine-producing nerve cells in the brain to replace those lost in PD.
Neurological – describing any condition or symptom that affects the nervous system.
Neurology – area of medicine that is concerned with the nervous system.
Neurone – another name for a nerve cell.
Neuroprotection – protection of nerve cells. This is a strategy for PD treatment in the future, with research into medications that can prevent nerve cell loss and damage in the brain.
Neurotransmitter – chemical that is present in the nervous system to carry messages between different nerve cells. Examples of neurotransmitters include dopamine, acetylcholine, noradrenaline and serotonin (the ‘feel good’ chemical). Dopamine is not the only neurotransmitter that is involved in PD.
OFF time – period when PD symptoms respond poorly to treatment, making movement difficult.
ON time – period when PD symptoms respond well to treatment, allowing good movement control. Sometimes it is associated with dyskinesias (‘peak-dose’ dyskinesias).
ON-OFF fluctuations – changes between good and bad periods of movement control. These correspond to how well the medication is working, and generally appear after many years of treatment with levodopa.
Orthostatic/postural hypotension – low blood pressure in response to a person standing up quickly from a sitting or lying position. It is caused by the blood rushing down to the lower body as the person becomes upright, meaning that there is less supply to the brain and, in turn, this can cause effects such as dizziness. It can be prevented/minimised by taking more time to stand up.
Osteoporosis – wasting disease of the bones.
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