Symptoms
- Fluctuation in alertness and speed of thought processes – this may vary throughout the day or over several days and can impact upon the ability to cope with daily tasks
- Decision making, problem solving, memory and word finding (often known as ‘tip of the tongue’ phenomenon) tend to become harder over time
- Short term memory span deteriorates, affecting the ability to recall when events have occurred
- Confusion may occur when carrying out relatively simple tasks
- Doing more than one thing at a time can be difficult, for example walking and talking
- Visual hallucinations, sometimes associated with delusions1, may occur
- Changes in personality, for example irritability, being withdrawn, lack of interest in one’s appearance, becoming obsessive, having difficulty in controlling emotions, anxiety
- Communication is also very likely to become more difficult for people with both Parkinson’s and dementia as each condition can impact on the skills used in effective communication, particularly in the late stages of the illnesses. The way we articulate and use words, the words we use, volume, tone and understanding might all be affected and so communicating with other people can be challenging.
Contributing factors to communication difficulties include:
- facial and body language, as well as responses to verbal and non-verbal cues - these may be affected by Parkinson’s and can sometimes make dementia appear worse to observers than it really is. Conversely, reduced expression may mask dementia
- slowness of thought or bradyphrenia - a symptom of Parkinson’s which might make responding to questions take considerably longer than expected. This can sometimes be mistaken as a sign of dementia when it is an isolated symptom
- depression - may also result in slowness of thought, so it is important that depression is treated and excluded as a contributory factor to dementia
- the ‘on-off’ phenomenon - this can confuse things because when medication is no longer working effectively (‘off’) a person may appear unresponsive and this can be misinterpreted as a sign of cognitive impairment. But when medication starts to work effectively again (‘on’) such seeming impairment may quickly disappear
- speech and swallowing difficulties - these are not uncommon in Parkinson’s and can be challenging when combined with dementia. A speech and language therapist will be able to advise on such problems. For further information see Speech & Language Therapy.
Over time, the ability to remember words is often affected, vocabulary can become limited and humour less understood. Automatic responses, such as ‘hello’ or ‘goodbye’ tend to be retained for longer, with responses requiring more careful thought processing being lost sooner.
Responses can be given out of sequence, or appear seemingly self-centred as it becomes more difficult to relate to others in the conversation. This can be interpreted as a lack of interest in others. It may also become harder to follow a conversation and this sometimes results in a person rambling and not making sense, becoming confused or perhaps repeating a few limited phrases over and over as they forget what they have already said.
For tips to help with communicating with people with Parkinson’s, see carers.
Diagnosis
Dementia and other cognitive difficulties are generally diagnosed by talking with the person and their carer or family and discussing their concentration, memory, language and problem-solving skills.
Recognised ‘rating scales’ are also used and these are comprised of carefully chosen questions, the responses to which score points indicating whether or not difficulties are present. Rating scales are also useful in monitoring improvement or decline during and after treatment.
For more subtle or complex difficulties a neuropsychologist - a psychologist with expertise in how behaviour and cognitive abilities are affected by brain structure and symptoms – may also make a more detailed assessment. This can be particularly helpful in differentiating Parkinson’s from other illnesses which give rise to dementia, such as Alzheimer’s disease, stroke or Dementia with Lewy Bodies.
Other factors, such as the onset of dementia in the very early stages of living with Parkinson’s or unusual symptoms, could suggest that Parkinson’s alone is not the sole cause. In such cases your doctor may recommend brain scans and blood tests to search for other treatable causes, for example thyroid disease or vitamin B12 deficiency.
