Parkinson's Disease

Music Cognition Lab and Parkinson's Disease and Movement Disorders Subspecialty Clinic

Parkinson’s disease is a gradually progressive neurodegenerative disorder. It usually occurs in the fifth or sixth decade. However, the occurrence in young patients is also not so uncommon. Parkinson’s disease is the second most common neurodegenerative condition next to Alzheimer’s dementia.
 
Parkinson’s disease is a heterogeneous disorder characterized by varying clinical presentations, age of onset, types of nonmotor symptoms, and different rates of progression. While some patients have a relatively benign disease course with favourable response to dopaminergic therapy, others appear to progress more rapidly. Many patients have a greater number of nonmotor symptoms while others do not.

SYMPTOMS
Patients who are diagnosed with this condition may show different signs and symptoms in the beginning. Sometimes, it may not even be noticed in the initial stages. Broadly the symptoms of this condition can be divided as motor and non-motor symptoms.
 
The following are key features or clinical symptoms:

1. Motor symptoms like slowness of movements, tremulousness, rigidity and balance impairment. Most often the illness begins with obvious changes in motor functions. The changes in motor functions may be observed on one side of the body and later include both sides.
2. Non-motor symptoms like mood and sleep disorders, reduced sense of smell, constipation, urinary problems as well as range of difficulties in mental functions (or cognitive functions) such as attention, memory, planning etc. 

Motor Symptoms

• Tremors: Tremors can be one of the initial symptoms which can appear. These can be present when one is sitting idle or not doing any activities. The other kind of tremors can be present when one engages in form of task or an action. The tremulousness can affect daily activities such as holding an object like cup of tea or spoon.
• Rigidity: Stiffness of arms, legs or joints and can restrict the necessary movement of affected side.
• Bradykinesia: Slowness of movement and may occur during starting of movement or in its continuation.
• Postural instability: Unstable posture or balance dysfunction, appears later in the course of the disease.  It can increase the risk of falls and increased nursing-home placement among the affected patients.

Non-motor Symptoms
A wide array of non-motor symptoms (NMS) is seen in patients with Parkinson’s Disease. ​Some of the common NMS include:

• Emotion related difficulties- Feeling isolated and lonely or feeling anxious
• Considerable reduction of drive to engage in goal-directed activities such as learning new things
• Ache and pains in joints or body, numbness and fatigue,
• Reduced smell perception.
• Constipation
• Urinary disturbances
• Sleep disorders includes insomnia and sometimes enactment of dreams in the sleep
• Cognitive difficulties such as trouble paying attention or remembering things.

During medication off states, patients may experience worsening in mood, anxiety, sweating and temperature irregularities, pain/numbness, and other symptoms. ​Nonmotor symptoms during medication on states may include mania, agitation, delusions, paranoia, and impulsivity.​

CAUSES
Parkinson's disease is caused due to loss of dopaminergic neurons in the part of the brain known as substantia nigra and by the presence of Lewy bodies in the brainstem. Motor symptoms become evident when 60% to 80% of dopaminergic neurons are lost in the pars compacta of the substantia nigra. ​It is estimated that 5% to 10% of patients have a genetic etiology for the disease. It has also been suspected that transition series metals such as manganese or iron, especially those that generate reactive oxygen species and/or bind to neuromelanin induces Parkinson’s disease. 

TREATMENT
A variety of therapeutic options are available for Parkinson’s disease, which targets both motor and nonmotor symptoms. Disease severity and duration determines the management of patients with Parkinson’s disease.

Pharmacological Treatment: From the pharmacological treatment point of view, dopamine replacement therapy is provided to patient which acts to enhance the dopaminergic activities in the brain in order to alleviate the symptoms caused due to its depletion. Before the start of dopaminergic treatment, patient’s age, comorbid condition, employment status and other quality-of-life issues has to be considered. ​Levodopa is considered to be the gold standard for dopamine replacement therapy in Parkinson’s disease.

Exercise: Exercise should be encouraged for all patients with Parkinson disease as long as it is performed safely. Exercise modalities include core strength training exercises, tai chi, yoga, boxing, and dance.

NEUROPSYCHOLOGY AND PARKINSON'S DISEASE

Neuropsychological Evaluation: Patients are assessed to identify any neuropsychological deficits in attention, memory, reasoning, planning, information processing, language etc. and based on the deficits found standardized cognitive retraining is done. These neurocognitive deficits are closely related to overall quality of life and overall functionality of the patient.

Cognitive Retraining: Cognitive retraining or remediation is a promising avenue as a non-pharmacological treatment option for cognitive impairments. Studies have shown promising results in improving cognitive deficits thus improving quality of life among persons with Parkinson’s disease.

MUSIC AND PARKINSON'S DISEASE

Music Based Intervention in Parkinson’s Disease: Music based interventions in the recent times is being used to help patients with neurological diseases including Parkinson’s disease.

• Neuroscience research has demonstrated that music can positively impact cognitive and emotional well-being and movement-related symptoms in person with Parkinson’s disease.
• It has been found that music can stimulate the production of neurotransmitters namely, dopamine and serotonin which are found to be reduced in individuals suffering from the condition.
• Music can also activate specific areas of the brain responsible for speech and communication.
• Music increases blood flow and the secretion of dopamine, which is depleted in Parkinson’s disease, which also regulated motivation and goal-directed behaviour.

Music-based intervention can be active as well as receptive. Active intervention involves multiple components analogous to training and music learning i.e, creating music, playing an instrument, singing, or musical improvisation, repetitive movements coupled with auditory feedback and extensive cognitive processing whereas, receptive intervention includes music listening that is administered by a credential music therapist. Technically, music-based intervention include, Rhythmic auditory cueing, Rhythmic auditory stimulation, Music therapy sessions (choral singing, voice exercise, rhythmic and free body movements, and improvisational music therapy techniques).

Music and Brain Areas: Brain areas involved in music and rhythm perception are closely related to those brain areas that regulate movement such as the motor areas of frontal lobe, cerebellum and basal ganglia as well neurocognitive and emotional functions. Music has the ability to activate the key areas of the brain during rhythm perception and serve as an important compensatory purpose.