Parkinson's Disease
From Psy3242
Contents |
Overview
Parkinson’s disease, otherwise known as PD, is the second most common neurodegenerative disease. The disease was named after its discoverer, James Parkinson in 1817. Parkinson’s disease begins to show side effects when about 80% of the nerve cells in the substantia nigra, part of the basal ganglia, die and become impaired. These cells are responsible for the production of dopamine, a neurotransmitter that regulates our motor coordination and functioning. The substantia nigra is incharge of dopamine production that is carried through two different pathways “direct” and “indirect”. The direct pathway facilitates movement. In PD, this area usually becomes less active, whereas, the indirect pathway becomes more active, in charge of inhibiting unwanted movements. The disease can be considered “idiopathic”, meaning that it has no known cause, or “secondary”, meaning it results from genetics, the post encephalitic epidemic, head trauma, MPTP, or Lewy bodies in the brain. Patients with PD are described as, “intellectually alert humans, in a disobedient body”. Parkinson’s is a terminal illness, but is a very slow process, so it is often that people die of unrelated illnesses before PD takes their lives.
Symptoms
Tremors
Dystonias, or persistent muscle spasms, are common during resting states and usually not present in deliberate movements. These tremors cause frequent trembling of the limbs.
Slowness of Movement
Bradykinesia, the slowed ability to initiate and maintain movements, is a common side-effect in PD patients. Repetitive movements such as tapping and clapping are frequent in their behavior. Once movement is initiated, most of the time patients are able to continue the movement fluidly, until they become distracted or interrupted. This slowness also is exhibited in their coordination, they are unable to move their limbs quickly, or carry out planned motor tasks. Patients try to find “tricks” to help them initiate movements, external cuing. For example, a pattern on the floor or hearing music sometimes helps patients to start their motions. As PD progresses, it can eventually lead to Akinesia, or the inability to move spontaneously at all.
Rigidity
Muscular rigidity is a symptom common of PD. Cogwheel rigidity, a type of stiffness characterized by jerks associated with forcing a limb to move, is another common indicator of this disease. The muscles cycle through loose, then tense, then loose, then very tense phases, making the patient very tired. A “masked” appearance to the face makes the patient seem emotionless because of their inability to control their facial muscles. When muscles tense simultaneously, the sensation can be very painful.
Difficulty with Balance
Patients can experience trouble walking. An unbalanced gait can lead to a shuffling walk. This shuffle is typical of Parkinson’s patients and some experience tripping and falling frequently because of it.
Difficulty with Speech
Some Parkinson’s patients are atonal and hard to understand. Bradykinesia plays a role in language production, as well, making it difficult to speak. Patients sometimes have problems with excessive drooling and trouble swallowing.
Sleep Complications
PD patients have problems falling asleep, staying asleep, restless leg syndrome, and sometimes nightmares as a result of medications or the actual disease itself. Also, a possible reason for sleep complications could be because of a patients inability to toss and turn to make themselves comfortable.
Depression
Depression has been noted to be a symptom associated with PD for 25-40% of patients because of the damper the disease has put on their life and side-effects of the medications.
Cognitive Executive Dysfunctions
Because dopamine regulates the prefrontal cortex, problems associated with frontal lobe functioning can sometimes occur. Dementia is a symptom, but not as common as the others. Patients that experience these executive dysfunctions exhibit difficulties planning, organizing, carrying out cognitive and motor plans, trouble completing a Rey Complex Figure test, difficulties with the Wisconsin Card Sorting Task, problems with spontaneous recall of memory problems without external cues, and bradyphrenia. Bradyphrenia is a condition in which the patient has a slowed reaction time and slowed thinking, although this could be associated with their motor deficiencies.
Skin Sensations
From time to time, PD patients can experience a tingling feeling in their limbs.
