A step-by-step procedure for calculations based on a determined set of operations and rules (see
Case definition).
Alternate level of care:
Care provided in an acute care hospital for patients deemed well enough by their care team to be cared for elsewhere. Patients receiving this level of care are usually awaiting transfer to a long-term care facility or some other form of supported living.
Alzheimer’s disease and other dementias:
Alzheimer's disease is a degenerative disease of the brain with characteristic pathological features and is the most common form of dementia. Dementia is a syndrome characterized by loss of memory, the ability to think, as well as changes in mood, behaviour and ability to communicate. Other common types of dementia include vascular dementia, frontotemporal dementia, or Lewy body dementia, each with distinct clinical and pathological features. In this report, the term ‘other dementias’ includes these forms as well as instances of dementia not classified by type.
Amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease):
A disease that causes progressive muscle weakness and paralysis due to the degeneration of the upper and lower motor neurons in the brain and spinal cord.
Anterior horn cell disease:
A classification of diseases associated with the anterior horn cells located in the spinal cord. Includes ALS.
Brain injury (traumatic):
An injury of the brain due to trauma (most often caused by vehicle crashes, falls, or sports activities) that can result in effects that range from mild and transient symptoms of concussion to profound and permanent impairments of neurological function.
Brain tumour:
Classified either as primary (if it arises from cells within or surrounding the brain) or secondary (if due to metastasis originating from tumours in other parts of the body). Primary brain tumours can be benign or malignant. Depending on their location and size, brain tumours can cause a variety of neurological problems including seizures, headaches, or focal neurological symptoms and signs such as weakness, clumsiness, and impaired vision, sensation, or speech.
Caregivers (informal and formal):
As used throughout the Study and its projects, informal care refers to care provided by family, friends, and neighbours, while formal care refers to health care workers.
Case definition:
In a health surveillance context, the criteria that must be met by an individual to be identified as having a specific condition. More complex case definitions usually include an algorithm that specifies, for example, how many codes, from what data source, and within what time period are required to meet the case definition (e.g. one hospital admission or three or more physician codes for a particular condition during a two-year period).
Cerebral palsy:
A non-progressive but not unchanging disorder that affects the ability to move or maintain balance and posture that is caused by an insult to, or an anomaly of, the developing brain.
Comorbidity:
Traditionally referred to as diseases, disorders, or conditions that occurred at the same time as another disorder but were not related to it causally or as a complication. As understanding of the biology of specific diseases has advanced, the meaning of some associations has changed. For example, mood disorders, once considered a comorbidity of Parkinson's disease (as well as several other neurological conditions), are now interpreted as a possible early manifestation of this condition.
Footnote 54,Footnote 55 In this report, the term is used in both its traditional sense (e.g. the SLNCC 2011–2012 Project
[16]) as well as more broadly as ‘other diagnoses’ recorded in databases along with targeted neurological conditions (e.g. the BC Administrative Data Project
[1]).
Confidence interval:
A statistical measurement of the reliability of an estimate. Narrow confidence intervals indicate greater reliability than those that are wide. The 95% confidence intervals indicate the ranges of values that are likely to include the true value 19 times out of 20.
Continuing care:
Health, social, and support services, which may include respite and palliative care, offered on a prolonged basis through home care programs or in long-term care facilities such as nursing homes.
Direct costs:
Monetary valuation of resources associated with health care paid for by public or private health insurance or by individuals and their families.
Dystonia:
A movement disorder that causes muscles to contract involuntarily, forcing all or part of the body into repetitive, often twisting movements. Dystonia may be generalized (affecting multiple muscle groups) or focal (affecting only a single body area).
Electronic medical record:
A digital version of a paper chart containing the complete patient’s medical history from one practice, mostly used by health care providers for diagnosis and treatment.
Footnote 56
Epilepsy:
A neurological disorder in which sudden bursts of electrical activity in the brain produce ‘seizures’ that can vary in frequency and form as a brief stare, an unusual movement of the body, a change in awareness, or a generalized convulsion. Most seizures last a few seconds or a few minutes.
Episodic:
Condition or symptom that presents irregularly or on occasion and can be categorized as separate events.
Estimate:
An approximation of the true value of a characteristic of a population. As used in this report, estimates derived from a sample of the entire population currently represent the best available information.
Health administrative data:
Collections of information on the delivery of health care services. In Canada, health care databases of the provincial and territorial governments collect and store information relevant to the administration of universal medical care insurance. The main sources of health administrative data pertain to hospital services, physician billings, and prescription drugs. Depending on how data concerning specific health conditions are captured, they can also be used for surveillance purposes, such as estimating disease prevalence and incidence.
Health Utilities Index score:
A measure of health-related quality of life, the Health Utilities Index – Mark 3 (HUI-3) is comprised of eight attributes: cognition, mobility, dexterity, speech, vision, hearing, emotion, and pain and discomfort. HUI-3 scores fall between a minimum value of -0.36 (worse than dead), through to 0.0 (dead), to a maximum value of 1.0 (full health). Disability categories in this report were derived from the HUI-3, with scores lower than 0.7 representing ‘severe disability’.
Huntington’s disease:
An inherited disorder that causes cells in specific parts of the brain to degenerate. Symptoms include emotional turmoil (depression, apathy, obsessive behaviour), loss of mental function (inability to focus, think and recall, or make decisions), or physical deterioration (weight loss, involuntary movements, diminished coordination, inability to walk, talk, or swallow).
Hydrocephalus:
A neurological condition in which excess cerebrospinal fluid accumulates in the brain cavities (ventricles). Hydrocephalus can be congenital (due to abnormalities of the developing brain), acquired (due to complications of intracranial haemorrhage, meningitis, head injury, or brain tumour), or idiopathic (due to an unknown cause). Depending on several factors (age of onset, rapidity of development, and severity) hydrocephalus can damage brain structures and cause neurological symptoms, including cognitive impairment or gait disorder.
Incidence:
The number of new cases of a disease or condition occurring in a given time period in a population at risk. Incidence can be expressed as an incidence proportion (the number of new cases within a specified time period divided by the size of the population initially at risk) or an incidence rate (the number of new cases per population in a given time period, expressed as new cases per number of person-years).
Indirect costs:
Monetary valuation of economic production and productivity lost due to sickness, disability, or premature death.
International Classification of Diseases (ICD):
A health care classification system that assigns diagnostic codes to diseases. The tenth revision of the ICD, known as ICD-10 (ICD-10-CA in Canada), is currently used to code data on hospital separations (discharge, transfers, and death) in all provinces and territories of Canada. The ICD-9 is still used as the basis for physician billing codes in many Canadian provinces and territories.
Meta-analysis:
The statistical synthesis of data from several studies that address a similar question.
Microsimulation
To project the future trajectory of the population, microsimulation models mathematically simulate the life course of representative (synthetic) persons from their birth to their death through exposure to multiple risks to health, development and progression of chronic diseases, and impairment of health. The models project health and economic outcomes useful for planning and policy decision-making: incidence and prevalence, health-related quality of life, survival, cost of health care, production lost to working-age disability, and death.
Migraine:
A type of recurrent throbbing headache that is often associated with nausea and even vomiting, sensitivity to light and sound, and, in about a third of those affected, visual or sensory auras.
Multiple sclerosis:
An autoimmune disease characterized by disseminated patches of demyelination (called plaques) in the brain and spinal cord. Multiple sclerosis is unpredictable, affecting vision, hearing, speech, memory, balance, and mobility, often in a pattern of relapses and remissions.
Muscular dystrophy:
A group of genetically-transmitted diseases characterized by progressive weakness and wasting of the muscles that control voluntary body movement. Different types of muscular dystrophy have distinct patterns of muscle involvement, age of onset, rate of progression, and type of inheritance. Even among individuals with a specific type of muscular dystrophy, symptoms and severity can be quite variable.
Parkinson’s disease:
A neurodegenerative disease resulting from the progressive loss of brain cells that produce dopamine, a chemical that carries signals between nerves in the brain. The four main features are: rigidity or stiffness of the arms, legs, or neck; tremor (usually of the hands); bradykinesia (slowness and reduction of movement); and postural instability (loss of balance). The terms parkinsonism or parkinsonian syndrome are used to describe the motor features (rigidity, tremor, bradykinesia, or postural instability) whether they are due to Parkinson's disease, other brain diseases, or the side effects of certain medications.
Patient registry:
A systematic collection of data related to patients with a specific diagnosis or condition that serves a predetermined purpose. For example, patient registries can provide epidemiological data that help assess disease burden or evaluate therapeutic measures.
Prevalence:
The frequency of a disease or condition in a population, expressed as the proportion of the population that has the disease or condition. Prevalence provides a measure of the burden of the disease in the population.
Progressive:
Disease or condition that shows deterioration or worsening over time.
Qualitative synthesis:
Systematic but non-statistical analysis (as opposed to a meta-analysis) of results and findings from qualitative or quantitative studies identified through a systematic review of the literature.
Range (of data):
The difference between the largest and smallest value in a set of observations.
Relative risk and population attributable risk:
Relative risk is a measure of the contribution of a risk factor to the development of a disease. It is calculated as the ratio of disease incidence in those ‘exposed’ to the risk factor to the disease incidence among those ‘not exposed’ to the risk factor. The population attributable risk takes into account both the relative risk and the prevalence of the risk factor. This is important because a high relative risk may indicate that a factor is devastating when it occurs, yet its occurrence may be so infrequent that its broader impact on population health may be relatively minimal.
Rett syndrome:
A rare genetic developmental disorder of the brain that occurs almost exclusively in girls. Girls with Rett syndrome usually develop normally until six to 18 months of age, whereupon their development slows and there is a regression of communication skills, loss of hand dexterity, slowing of the normal rate of head growth, and the appearance of stereotyped hand movements and gait disturbances. Other problems may include seizures, disorganized breathing patterns, or excessive irritability.
Risks and risk factors:
Risk is the chance that an event will occur, and is usually expressed as a proportion or frequency with a value between 0 (no risk) and 1 (definite risk). As used in relation to health and disease, a risk factor is a variable (e.g. a behaviour, condition, or exposure) that affects the risk of disease occurrence.
Spina bifida:
A spectrum of developmental disorders in which there is a defective closure of the neural tube during the first four weeks of pregnancy. This neural tube defect results in varying degrees of paralysis of the lower limbs and impairment of bladder or bowel function.
Spinal cord injury:
Damage to any part of the spinal cord. Depending on the level of the spinal cord that is injured and the severity of the lesion, the arms and legs (quadriplegia) or legs (paraplegia) may be affected by weakness, paralysis, or loss of sensation. Bladder, bowel and sexual function are often affected as well. Spinal cord injuries are most frequently caused by vehicular crashes, falls, or sport/recreational activities.
Static:
Disease or condition that remains stable or shows little change.
Stroke:
A sudden loss of brain function caused by an interruption of the flow of blood to the brain (ischemic stroke) or the rupture of blood vessels in the brain (haemorrhagic stroke). The effects of a stroke depend on where the brain was injured, as well as how much damage occurred. A stroke can result in one-sided arm and leg weakness, known as hemiplegia, or can cause other impairments of movement, coordination, vision, speech, memory, or in the capacity to think.
Surveillance:
As used in public health, surveillance is the ongoing systematic collection, analysis, and interpretation of data on population health that is used to plan, implement, and evaluate public health practice.
Footnote 57
Systematic review:
A critical assessment and evaluation of a set of research studies that address a particular clinical issue. A systematic review may also include a quantitative pooling of data, called a meta-analysis.
Footnote 58
Tourette syndrome:
A neurological disorder characterized by tics, which are involuntary, rapid, sudden movements or vocalizations that occur repeatedly in the same way. The onset of symptoms is usually before the age of 18 years, with the appearance of facial tics (rapid eye blinking or mouth twitches), involuntary sounds (such as throat clearing and sniffing), or tics of the limbs. Symptoms often lessen in early adulthood.
