Defining Symptoms

I have had a number of e-mails asking to clarify the difference between various symptoms. I would like to stress I am not a doctor, merely a patient sharing my experiences with you, but hope the following descriptions help explain.

Apathy: Not caring and disinterested, having reduced sensitivity and emotions, a lessened interest in things that used to matter.

Dementia: A decline in intellectual function, unable to retain information, leading to some degree of social impairment as the result of reduced memory or problem-solving abilities.

Depression: A collection of several symptoms, which can easily be confused with other symptoms. Continual sadness or an inability to feel pleasure are the main features. Depression also may include: fatigue, poor sleeping, weight loss or gain, soft voice, lack of patience and irritability.

Fatigue: A sense of immense lack of energy, which is completely different from just feeling sleepy. This is a very common and debilitating problem with Parkinson's.

A patient may suffer from just one or two or all of the above, but these symptoms should not be confused with each other - they are individual, and need to be treated as such. To give you an example of how easy it is to confuse the above symptoms and come to the wrong conclusion, here is a simple example: I'm often in chronic pain, therefore someone who does not know me, could easily think I'm depressed, since chronic pain makes one understandably irritable, it's not easy to smile when in terrible pain, it  impedes sleep, induces lack of appetite, and who has the strength to talk loudly or enjoy an activity that normally would bring pleasure. A neurologist certainly has his work cut out, ascertaining the correct diagnosis.