Definition of Dementia
Dementia is a deterioration in the mental state characterized by deficits in higher cortical functions (i.e., memory, language, visuospatial skills and executive functions).
- Alzheimer´s disease is not synonymous with dementia, but is the most common cause (75%).
- Dementia is not a feature of normal aging and is always indicative of pathology.
- Mild cognitive impairment (MCI) is a transition stage to AD, 10% convert per year to AD. Analogous to glucose intolerance and diabetes.
Dementia as symptom complex
Dementia per se is not a diagnose, but a symptom complex, which can occur as the consequence of different organic diseases. It is therefore without knowledge of the cause more suitable to refer to it as a dementing syndrome, which is according to ICD-10-criteria a state, that is characterized by:
- impairment of the memory, as well as
- impairment of at least one further cognitive function like thinking, orientation, perception, calculating, learning ability, language and the ability to judge, furthermore including
- change of emotional control, social behavior and motivation
- without impairment of consciousness
- for a minimum duration of 6 months
Epidemiology of Dementia
Alzheimer’s disease as the main reason for dementia
The most common reason for dementia is with 2/3 of all disease cases Alzheimer’s disease (synonym: Alzheimer’s dementia), followed by vascular dementia (15%) and combination forms of vascular and Alzheimer’s dementia (15%). The remaining 10% of disease cases are made up by neurological diseases and other reasons for reversible or irreversible dementing syndromes.
Symptoms of Dementia
Gradual begin of dementia
First warning signs for dementia are often subtle and only apparent to close relatives, not to the affected person himself. They include the repetition of the same question, the narration of the always identical short story and the misplacing of things (often others are being accused of having misplaced the item then). A secure handling of financial issues is lost, as well as grooming.
An extraordinary psychological strain arises for the dementia patients, especially during early phases of the disease. They suffer from apathy, aberrant motor behavior (which means wandering aimlessly), eating of non-edibles, irritability, aggression, sleep disturbances and depression.
Insecurities of fine motor skills and a decreased vocabulary accrue when the disease progresses. Inner self-reflection shrinks and unfounded outbursts of anger and violence occur. In cases of progressed dementia, close relatives are no longer recognized, and the ability to master the simplest everyday tasks is lost. Musculature shrinks thus patients suffer from urinary and fecal incontinence. Another characteristic is small tripping steps.
The disease, in the end, leads to bedridden patients, who are totally dependent on nursing. Most patients only survive due to the implantation of a PEG tube as the ability to swallow is lost. Patients die due to pneumonia or heart failure.
Note: Especially patients with Lewy-Body-Dementia suffer from hallucinations, which are mostly dominated by fear and handle topics like kidnapping or similar.
Diagnostic Investigation of Dementia
Neuropsychological test devices for the diagnosis of dementia
The earlier stated ICD-10-criteria need to be fulfilled in order to diagnose a dementing syndrome. Neuropsychological test devices like the Mini-Mental-State-Examination (MMSE), the Clock Test and the DemTect Test are suitable for diagnosis and quantification of cognitive deficiencies.
The MMSE is a test for the detection of cognitive impairments. It includes questions and tasks in 10 categories:
- Orientation: 10 questions concerning temporal and spatial orientation (max. 10 points).
- Retentiveness: Repeating of 3 words, maximum 5 repetitions (max. 3 points).
- Attentiveness and calculating: Progressing subtraction of 7 starting with 100 (max. 5 points with 5 correct calculation steps).
- Memory: Remembering of the 3 words from the beginning (max. 3 points).
- Naming: The correct naming of 2 shown items (watch, pencil) (max. 2 points).
- Repeating, for example, “without fuss or quibble” (max. 1 point).
- Active part and speech comprehension: “Take this piece of paper in your hands, fold it in the middle and put it on the ground” (1 point for every correctly performed action, max. 3 points).
- Reading: Reading and performing an instruction (for example: “close your eyes”) (max. 1 point).
- Writing: Write any sentence (max. 1 point).
- Drawing: Copy a given geometric figure (2 interlocked pentagons) (max. 1 point).
The maximum obtainable score of the MMSE is 30 points. Points under 26 are suspicious in terms of mild dementia.
|27 – 30||No dementia|
|26 – 20||Mild dementia|
|10 – 19||Moderate dementia|
|< 9||Severe dementia|
The Clock Test serves for the examination of spatial imagination and visual thinking. Here, the patient is supposed to draw the chronograph dial of a clock including a time set by the examiner (e.g. ten to twelve). The presentation of the dial (recognisability of the clock, correct filling in of the digits), the position of the watch hands (correct presentation of the set time) and the size of the watch hands in relation to each other is evaluated with the system of school grades.
Differential Diagnosis of Dementia
The knowledge of possible reasons is indispensable for further examination of a dementing syndrome. It is principally differentiated between potentially reversible and irreversible dementing syndromes, whose reasons are going to be presented in the following:
Potentially reversible dementing syndromes
Potentially reversible dementing syndromes can arise in the scope of different diseases and should be clarified as possible reasons at the beginning of every dementing syndrome:
|Overview over potentially reversible dementing syndromes|
Irreversible dementing syndromes
Irreversible dementing syndromes include different diseases, which are characterized by structural brain damage. Those include:
- Alzheimer dementia and vascular dementia as the main forms of dementia,
- Frontotemporal dementia
- Lewy-body dementia
- Dementia due to Parkinson’s disease
- Dementia due to Creutzfeld- Jakob disease
- Dementia due to Huntington’s disease
Anamnesis of Dementia
Anamnesis has with regards to the various reasons of a dementing syndrome an essential importance. The subjective descriptions by the patient (personal anamnesis), as well as descriptions by close relatives like spouse or children, can give important hints for finding the underlying disease. It should be asked for:
- Primary diseases (exclusion of a reversible dementing syndrome)
- Development (subtle or acute beginning) and expression of the symptoms (impairments of daily living?)
- Family anamnesis (Huntington’s disease, Parkinson’s disease)
- Cardiovascular risk factors/cardiovascular events in the past (vascular dementia)
- Prior trauma
- Attendant symptoms like for example change of personality (frontotemporal dementia), gait disorder or extrapyramidal movement disorders (Parkinson dementia, Lewy-Body dementia, subcortical dementia), visual hallucinations (Lewy-Body dementia), urinary incontinence (normal pressure hydrocephalus)
- Regular medication (dd: drug-induced reversible dementing syndrome due to digitalis- or benzodiazepine intoxication)
Physical Examination of Dementia
Physical examination includes a thorough internal and neurological examination with special regards to:
- Possible reasons for a reversible dementing syndrome
- Neurological disorders (reflex status, examination of brain nerves and motor skills)
- Extrapyramidal movement disorders
- Gait disorders
- Signs of an increased intracranial pressure (funduscopy)
Laboratory diagnostics and further instrument examinations
The following examinations belong to the standard repertoire of every dementia diagnosis:
- Lab: blood count, electrolytes, transaminases, bilirubin, gamma-GT, AP, creatinine clearance, urea, vitamin B12, folic acid, glucose, TSH
- Imaging: computer tomography or MRI (cerebral tumor? Bleeding? Atrophy? Infracted areas?)
- ECG (atrial fibrillation)
Other examinations should be carried out facultative depending on the suspected diagnosis. Those include:
- Laboratory examinations like lues- and borreliosis-serology, HIV test, CDT (alcohol abuse?), copper (Wilson’s disease) and B vitamins
- Diagnosis of cerebrospinal fluid (especially in cases of suspected normal pressure hydrocephalus, Creutzfeld-Jacob disease)
- EEG (repetitive triphasic waves with Creutzfeld-Jacob disease)
The correct answers can be found below the references.
1. What does not belong to the ICD-criteria of dementia?
- Impairment of memory
- Change of emotional control
- Symptoms for at least 6 months
- Affection of the consciousness
- Impairment of thinking, language and orientation
2. Which score refers to moderate dementia in the MMSE?
- 10 – 19 points
- 5 – 9 points
- 27 – 30 points
- 20 – 26 points
- 14 – 21 points
3. A 63-year old patient with his wife visits a primary physician. The patient seems to be apathetic and is not able to answer questions appropriately. Sometimes he just repeats the asked question and sometimes he looks at his wife in search for help. She reports that her husband has changed over the past few months. At first, she noticed his small step gait just as if his feet were glued to the ground. Afterward, her husband became more and more oblivious, misplaced stuff and did no longer care for his exotic birds, and, for some days now, he was incontinent. What is your suspected diagnosis?
- Parkinson’s disease
- Lewy-Body dementia
- Pick disease
- Creutzfeld-Jakob disease
- Normal pressure hydrocephalus