Dementia

This article is currently under review and may not be up to date. Please come back soon to see the finished work! (17/06/2019)

Original Editors - Leana Louw

Top Contributors - Leana Louw, Lauren Lopez, Simisola Ajeyalemi and Kim Jackson  

Definition

Dementia refers to a group of symptoms associated with a decline in mental ability. It is caused by disorders affecting the brain, and are described by a collection of symptoms affecting the brain. Dementia has an effect on thinking, behaviour and social interaction, as well as functional abilities[1].

Clinically Relevant Anatomy

Symptoms of dementia depend on the area of the brain affected by the underlying pathology e.g. vascular disease affecting particular vessels supplying a particular lobe of the brain. The hippocampus though is often involved and contributes to the well-known symptoms of memory loss.

Hippocampus

  • Centre of memory and learning
  • Cells in this region are normally first to be damaged in Alzheimer's disease[2], resulting in the common symptom of memory loss
  • Changes in hippocampal volume (a reduction) are seen with common patterns of ageing but are exacerbated in Alzheimers[3]

Epidemiology and Etiology

Epidemiology

Dementia affects approximately 47 million people worldwide and is projected to increase to 75 million in 2030 and 132 million by 2050[4]. Dementia is generally associated with age but early onset dementia also occurs.

Etiology

Damage to brain cells causes changes to cognitive, behavioural and emotional functions, causing dementia.

Different types of dementia has different causes. Common types of dementia are:

  • Fronto-temporal lobar degeneration dementia
  • Alcohol related dementia (Korsakoff's syndrome)
  • Creutzfeldt-Jacob disease

Risk Factors

Dementia risk factors can be categorised into modifiable and non-modifiable risk factors. Modifiable risk factors include physical inactivity, tobacco use, unhealthy diets and harmful use of alcohol. Further, certain medical conditions are associated with an increased risk of developing dementia, including hypertension, diabetes, hypercholesterolemia, obesity and depression. Other potentially modifiable risk factors may include social isolation and cognitive inactivity.[5][6][7] Non-modifiable risk factors for dementia include age and genetics. Age is the primary risk factor for dementia[4], although it is not a consequence of ageing while genetics can also increase risk. [8]

ANU Alzheimer's Disease Risk Index (ANU-ADRI) is an evidence-based, validated, tool aimed at assessing an individual's exposure to risk factors known to be associated with an increased risk of developing Alzheimer's disease in late-life(> 60 years)

  1. Diabetes mellitus:is a major vascular risk factor for developing dementia through mechanisms such as glucose-mediated toxicity which causes microvascular abnormalities and neurodegeneration[9]; also, evidence of impaired insulin receptor activation in Alzheimer’s disease [10] has led to suggestions that it might represent an insulin-resistant brain state.[11] It has been shown from several studies that the presence of type 2 diabetes in midlife is associated with increased risk of dementia, alzheimer’s disease, vascular dementia and cognitive impairment. Dementia risk with diabetes is further increased with longer duration and greater severity of diabetes. In a review of relevant studies, it was found that diabetes was associated with a 47% increased risk of any dementia, a 39% increased risk of Alzheimer’s disease, and a 138% increased risk of vascular dementia.[12]
  2. Physical inactivity: Exercising more in midlife is associated with a reduced risk of dementia.[13] Exercise is postulated to have a neuroprotective effect, potentially through promoting release of brain-derived neurotrophic factor (BDNF),[14][15] reducing cortisol, and reducing vascular risk. However, exercise alone does not seem to improve cognition in healthy older adults.[16] Report from a meta-analysis[17] of 15 prospective cohort studies showed that physical activity had a significant protective effect against cognitive decline, with high levels of exercise being the most protective. In a study[18] looking at the impact of physical activity on different brain structures in 120 older adults assigned to either a moderate intensity walking group or a stretching and toning group. In over a year, the stretching and toning group showed the age-appropriate reduction in the volume of their hippocampal region while the walking group showed an increase in the volume of their hippocampal region. This evidence demonstrates that increased physical activity can result in the growth of certain areas of the brain. The researchers also reported a significant increase in the memory function of the walking group.
  3. Depression: Depression doubles as a risk factor and a symptom of dementia. It is biologically probable that depression increases dementia risk as it affects stress hormones, neuronal growth factors, and hippocampal volume.[19] Cohort studies[20] with extended follow-up times show a link between number of depressive episodes and risk of dementia, which further reinforces the assertion that depression is a risk factor for dementia.However, a cohort study[21] suggests that midlife depression is not a risk factor for dementia.
  4. Smoking: Smoking is believed to be associated with dementia and cognitive decline[22] due to its effect on cardiovascular pathology. A meta-analysis[23] has shown that current smoking increased the risk of dementia (from any cause) by a significant amount (34% for every 20 cigarettes consumed per day). However, former smokers were found to have a similar risk profile to those who had never smoked. This suggests that by giving up smoking, individuals can potentially reduce their dementia risk to that of someone who has never smoked.
  5. Midlife Hypertension:has also been associated with increased risk of dementia in late life[24].
  6. Midlife obesity: is also linked to an increased risk of cardiovascular disease, vascular dementia and Alzheimer's disease. This has been shown from a recent systematic review and meta-analysis of observational studies conducted on about 600 000 individuals. Result showed that obesity (but not overweight) at mid-life increases the risk of dementia (RR = 1.33; 95% CI: 1.08–1.63)[25]
  7. Low educational attainment: Education has been related to lower dementia risk as it appears to protect the brain from cognitive decline. A study by Roe et al 2008[26] showed completing more years of education provides protection from the emergence of the cognitive symptoms of Alzheimer’s disease. The concept of cognitive reserve describes how education and cognitive stimulating may lower cognitive impairment.
  8. Hearing loss:it has also been associated with an increased risk for dementia or cognitive decline.[27] A recent meta-analysis of prospective cohort studies showed that the relative risk of hearing impairment on incident Alzheimer’s and MCI was 2.82 (95% CI: 1.47–5.42)[28]. In addition, a meta-analysis published by the Lancet Commission showed that hearing loss can almost double the risk of incident dementia (RR = 1.94, 95% CI: 1.38–2.73)[29]
  9. Social Isolation: Social disengagement has been shown to increase risk of cognitive impairment and dementia in older individuals[30]. A systematic review and meta-analysis of longitudinal cohort studies showed that lower social participation, less frequent social contact and loneliness were associated with higher rates of incident dementia.[31]

Clinical Presentation

Early signs of dementia are normally subtle, sometimes mimicking other patterns of ageing[1]. It can include[32][33]:

  • Progressive and frequent memory loss (mostly short-term)
  • Confusion
  • Personality changes
  • Apathy and withdrawal
  • Loss of functional abilities to perform activities of daily living

Although some cases of dementia are reversible (e.g. hormonal or vitamin deficiencies), most are progressive, with a slow, gradual onset. Certain symptoms, mostly behavioural and psychological, can result from drug interactions, environmental factors, unreported pain and other illnesses[33].

Diagnostic Procedures

General practitioners are usually the first port of call for diagnosis of dementia[1]. Making a diagnosis can be challenging. The NICE guidelines for dementia recommend the following process for making a diagnosis.

  • Take a history including cognitive, behavioural and psychological symptoms, and their impact on daily life. A history should be taken from the individual with dementia symptoms ideally also
  • A physical examination with blood and urine tests to exclude reversible causes of cognitive decline
  • Cognitive testing using a validated brief structured cognitive instrument such as: the 10-point cognitive screener (10-CS) the 6-item cognitive impairment test (6CIT) the 6-item screener the Memory Impairment Screen (MIS) the Mini-Cog Test Your Memory (TYM).

Diagnosis of the dementia subtype is critical for clinical management and anticipating the course of disease[1]. Certain types of dementia are diagnosed by medical history, physical examination, blood tests, and characteristic changes in thinking, behaviour and the effect on performance of activities of daily living. The diagnosis of the dementia subtype can be difficult to diagnose as many of the symptoms and brain changes overlap. Secondary care services normally assist in the diagnosis of the specific subtypes of dementia with the use of imaging[1] or examining cerebrospinal fluid[34].

Differential Diagnosis

Dementia can have different causes, and the following conditions need to be treated and/or excluded first:

  • Vitamin B12 deficiency[1]
  • Hormone deficiencies (e.g. thyroid problems)[1]
  • Depression[1]
  • Medication side-effects
  • Alcohol abuse
  • Overmedication
  • Infections
  • Brain tumours

Outcome Measures

The following list is from a review of useful outcome measures for dementia.

Management

Medical management should be sought as soon as symptoms start appearing, as some of the causes are treatable, and early diagnosis and management can minimise the disease process to allow most benefit from available treatments.

Symptoms include[34]:

  • Agitation, aggression, distress and psychosis
  • Depression and anxiety
  • Sleep problems
  • Parkinson's disease
  • Pain
  • Falls
  • Diabetes
  • Incontinence
  • Sensory impairment

Medication

The NICE guideline for dementia discusses pharmacological management of dementia according to subtype in depth. The following describes medications used to treat the symptoms of dementia[33]. It is important to note that not every individual with dementia will be prescribed every medication.

Antidepressants

Effectiveness is normally only seen after two to three weeks.

  • Types:
    • Tricyclic (amitriptyline, imipramine or dothiepin)
      • Side-effects:
        • Worsening confusion
        • Dry mouth
        • Blurry vision
        • Constipation
        • Dizziness in upright position (thus not recommended in Alzheimer's disease, as it can cause falls and injuries)
        • Difficulty with urination
    • Newer types of antidepressants have less side-effects
      • First line treatment: Fluoxetine, paroxetine, fluvoxamine, sertraline, citalopram and escitalopram
      • Side-effect
        • Headaches
        • Nausea
  • Commonly prescribed:
    • Antidepressants:
      • Amitriptyline (Endep) 
      • Citalopram (Cipramil, also Celapram, Ciazil, Talam, Talohexal) 
      • Dothiepin (Prothiaden, also Dothep) 
      • Doxepin (Sinequan, also Deptran)
      • Escitalopram (Lexapro) 
      • Fluoxetine (Prozac, also Lovan, Auscap, Fluohexal, Fluoxebell, Zactin) 
      • Fluvoxamine (Faverin, also Movax, Luvox, Voxam) 
      • Imipramine (Tofranil, also Tolerade) 
      • Mirtazipine (Avanza, Axit, Mirtazon, Remeron) 
      • Nortriptyline (Allegron) 
      • Paroxetine (Aropax, Paxtine, Oxetine) 
      • Reboxetine (Edronax) 
      • Sertraline (Zoloft, Xydep, Eleva, Concorz) 
      • Venlafaxine (Efexor)
      • Lithium carbonate (Lithicarb, Quilonum) - mood stabilizer

Antipsychotics

  • Neuroleptics/major tranquillisers such as:
    • Amisulpride (Solian) 
    • Chlorpromazine (Largactil)  
    • Fluphenazine (Modecate) 
    • Haloperidol (Haldol, Serenace) 
    • Moclobemide (Auroix) 
    • Olanzapine (Zyprexa) 
    • Promazine (Promazine) 
    • Quetiapine (Seroquel) 
    • Risperidone (Risperdal) 
    • Sulpiride (Dolmatil, Sulparex, Sulpitil) 
    • Trifluoperazine (Stelazine) 
    • Zuclopenthixol (Clopixol)
  • Treat agitation, aggression and psychotic symptoms
  • Side-effects:
    • Sedation
    • Dizziness
    • Unsteadiness
    • Shakiness, slowlessness, stiffness of limbs (resembles Parkinson's disease)

Hypnotics

  • Treatment of sleep disturbances
  • Side-effects:
    • Excessive sedation
    • Increased confusion
    • Unsteadiness
    • Long-term use: Tardive dyskinesia
  • Commonly prescribed:
    • Chloral hydrate (Welldorm) 
    • Clomethiazole (Heminevrin) 
    • Flurazepam (Dalmane) 
    • Nitrazepam (Mogadon also Alodorm) 
    • Temazepam (Femaze, Temtabs, Normison) 
    • Zopiclone (Imrest, Imovane) 
    • Zolpidem (Stilnoct)

Anxiety-relieving drugs

  • Benzodiazepine - short periods of anxiety
    • Short duration: Lorazepam, oxazepam
    • Long duration: Chlordiazepoxide, diazepam
  • Long term use not recommended
  • Side-effects:
    • Excessive sedation
    • Unsteadiness
    • Accentuation of confusion and memory deficits
  • Commonly prescribed:
    • Alprazolam (Xanax, also Alprax, Kalma, Zamahexal) 
    • Buspirone (Buspar) 
    • Diazepam (Valium also Antenex, Valpam, Ducene) 
    • Lorazepam (Ativan) 
    • Oxazepam (Alepam, Serepax, Minelax)

Anticonvulsants

  • Commonly prescribed:
    • Sodium valproate (Epilim also Valpro) 
    • Carbamazepine (Tegretol)
  • Reduce aggression and agitation

Cholinesterase inhibitors

  • Donepezil, galantamine, rivastigmine
  • Effects:
    • Improve memory and ability to perform activities of daily living (especially in Alzheimer's disease)
    • Slight effect on behavioural symptoms, mood, confidence, delusions, hallucinations
  • Side-effects (high dosages):
    • Increased agitation
    • Insomnia with nightmares

Non-medical Management

Alongside drug interventions, non-pharmacological interventions are used to treat the symptoms of dementia.

Non-pharmacological Management

  • Cognitive stimulation therapy[34][35] for mild to moderate dementia which has been shown to be as clinically effective and cost effective as acetylcholinesterase inhibitors[36]. Cognitive stimulation therapy can be administrated by anyone working with dementia patients; carers, nurses or occupational therapists[37].
  • Reminiscence therapy for mild to moderate dementia[34][38].
  • Cognitive rehabilitation or occupational therapy (working on functional goals of the individual and/or their carers[34]).
Lifestyle Modifications
  • Regular exercise and an active lifestyle[33]. Very effective in the management of the depression component of dementia.
  • Stimulating, personalised daily activities[34].
Exercise Therapy
Physiotherapy Management

Physiotherapy is not a modality used to treat the underlying cause of dementia, but exercise can be used in the prevention of dementia and minimising the effects of dementia e.g. reduced mobility and pain. In addition, a well rounded knowledge of dementia is important in the management of patients with dementia presenting to physiotherapy for other conditions.

Physiotherapists can play a role in customising exercise programmes. Research have shown positive effects that exercise can prevent or delay the onset of dementia, by slowing down the cognitive decline[39][40]. This can lead to improved quality of life and slowing down of functional decline expected with the disease process[40]. There is also some evidence that exercise therapy can improve the ability of people with dementia in performing activities of daily living[41].

Supporting Carers

People with dementia often live in independently in the community supported by formal and informal carers (family and friends). The burden on carers can be significant as dementia progresses in the individual cared for. As a result, carers report worse health outcomes compared to their peers[42][43]. Supporting carers is essential to helping people with dementia live in their own familiar homes and communities.

See the Physiopedia guides for carers here and here for further information on supporting carers of people with dementia.

Resources 

References

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