Lewy body dementia

November 12, 2012

Lewy body dementia

Lewy Body dementia is the second most common dementia, after Alzheimer’s. It is a progressive, degenerative condition with similar, and often overlapping, symptoms to both Alzheimer’s and Parkinson’s. Lewy Body Dementia (known as DLB) causes deterioration in both behaviour and memory as does Alzheimer’s and also the development of mild physical, motor system symptoms as with Parkinson’s. In addition, sufferers of DLB very often experience vivid, visual hallucinations.

Diagnosis

The diagnostic process for Lewy Body dementia is not dissimilar to that for Alzheimer’s and is generally designed to rule out other underlying causes for the symptoms that have prevented – there is, currently, no single diagnostic test for DBL other than a post-mortem.

The diagnostic process will involve all or some of the following -

  • Interviews with family and friends, as well as with the patient
  • Detailed medical history including medication.
  • Physical and neurological examinations
  • Appropriate laboratory testing
  • Psychological and/or psychiatric testing
  • Imaging scans such as CT, MRI, PET or SPECT

Psychological or psychiatric testing

A patient with suspected Lewy Body dementia will undertake a number of tests as part of a psychiatric/psychological evaluation, these will include -

  • Assessment of the presence of any depression using the Geriatric Depression Scale.
  • Examination of mental status – this is used to determine and assess memory function, concentration levels as well as other cognitive skills. It is perfectly possible for patients who meet all the criteria for Lewy Body dementia to have fully functioning cognitive skills – relying solely on mental status assessment is, therefore, not recommended as a diagnostic tool.
  • Neuropsychological testing – the intention of neuropsychological testing is to assess concentration and attention levels as well visual-spatial skills, this is particularly important in the early stages of the disease when problems with memory may not be apparent. This type of testing also gives an indication of the patient’s cognitive impairment and preserved abilities.

Treatment

Patients with Lewy Body Dementia are frequently unable to tolerate anti-psychotic medications – this makes the symptoms of delusions and hallucinations particularly difficult to treat. Anti-psychotic medications can cause a worsening of the symptoms of DLB and even induce catatonia and muscle rigidity; this type of medication has also been known to cause neuroleptic malignant syndrome in DLB patients – a potentially life threatening condition.

In the absence of any approved drugs for the treatment of Lewy Body Dementia it has been found that some of the drugs used in the treatment of Alzheimer’s are beneficial – those patients with DLB appear to respond well to cholinesterase inhibitors.

The use of drugs such as Sinemet, commonly used to treat Parkinson’s, have been seen to have some benefits in alleviating movement difficulties in DLB patients – however, these drugs also appear to worsen the symptoms of confusion, delusion and hallucinations.

Anti-depressants may also be used in order to treat sleep and mood disorders experienced by patients with DLB – however, again, these medications appear to increase both the confusion and motor system difficulties of those individuals.

Behavioral management techniques and some lifestyle changes, such as reducing caffeine intake and increasing activity levels, have been found to have benefits for some patients.

Prognosis

The progression of Lewy body dementia varies between individuals and is seen to fluctuate between periods of decline (which may be exacerbated by certain medications or other underlying infection or disease) and periods of improved function.

Once the symptoms of LBD begin to manifest an individual will have a life expectancy of between five and eight years, however, this is very much dependent on age, severity of symptoms and any other medical conditions. Some patients have lived for as long as twenty years with the disease, others for only two or three.

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