Hey hey readers! Welcome! In this 5-part blog series, I will take a deep dive into the world of Parkinson’s disease (PD). PD is near and dear to my heart, as I work with many patients with PD in my speech therapy job. I also spent years researching the dopamine (DA) and the dopaminergic (DAergic) system for my first Master’s degree in neuroscience. In addition to my work with patients with PD and my research into DA years ago, I am also a very devout yogi. Yoga has been incredibly transformative in my life, so I wanted to find out if yoga would be beneficial for people with PD (PWPD). So, for the past many months, I have been digging through many research studies to find a scientifically-based answer to this question – does yoga help improve symptoms of PD? Spoiler alert – yes, yoga is actually quite helpful for PD. But, more on this in part III, which will be entirely dedicated to reviewing what the research suggests about yoga’s impact on PD symptomology. Part IV will review other forms of physical activity (PA), such as dancing and resistance training, and the effects therein on PD symptoms. Part V will be super neuroscience-y, where I will go over the neurobiology of the brain areas affected by PD.
In general, PD is a neurodegenerative disease, progressively worsening over time. The usual age of onset is between 65-70 years of age. PD is typically known as a movement disorder, as motor deficits are the cardinal symptoms; however, as you will learn over the course of this series, PD affects way more than just motor skills. The majority of PD cases are idiopathic, meaning that they arise spontaneously where the cause is unknown, and a small percentage of PD cases are inherited from a family member.
In Part I of this series, I will go over the prevalence data and epidemiology as well as the clinical features and symptoms of PD. Read on to learn more about this common neurodegenerative disease.
Statistics and Prevalence Data
PD is the most common movement disorder, and it is the second most common neurodegenerative disorder, second only to Alzheimer’s disease. More than 10 million people worldwide are diagnosed with PD, and PD cases seem to be increasing in prevalence. Worldwide cases have doubled between 1995 to 2015, and another doubling of cases is expected by 2040. In the United States, about 1 million people are diagnosed with PD, and about 60,000 new cases of PD are diagnosed annually.
The incidence of PD increases with age, reaching a maximum around 80 years. Indeed, PD affects about 3% of the population aged 65 years and about 5% of the population in people over 85 years. The risk of PD is about 1.5 times higher in men than women. The annual treatment cost for PD is estimated to be about 25 billion dollars.
Clinical Features and Symptoms
PD is characterized by the presence of predominantly motor symptoms and a diversity of nonmotor symptoms. Essentially, PD is a movement disorder, characterized by a significant reduction in muscle control compared to pre-existing condition. As the disease progresses, spontaneous movements decrease. The motor and nonmotor manifestations of PD can cause quite substantial limitations for activities of daily living (ADLs). Specifically, the motor symptoms negatively affect functional mobility, balance, and gait, and they increase the risk of falling. The nonmotor symptoms have an immense impact on quality of life (QOL), significantly reducing QOL for those with PD.
Motor Symptoms
The typical, or cardinal, motor symptoms experienced by PWPD are bradykinesia, muscular rigidity, static or resting tremor, and postural instability. Bradykinesia is defined as slowness of initiation of voluntary movement with progressive reduction in the speed and amplitude of movement. What I typically see and hear from my patients with PD is that certain parts of their body just don’t move when they are trying to move them, or they move very slowly and/or with a very small range of motion (ROM). Muscular rigidity is defined as stiffness, where muscles and surrounding connective tissue becomes very tight and tense, making it difficult to move a particular muscle. Static or resting tremor is defined as a 4-6Hz oscillation, or repetitive movement, of a body part, such as the fingers or lips. Postural instability is defined as a loss of the ability to maintain proper posture, where PWPD often develop a flexed, or hunched over, posture. This flexed posture can lead to difficulty balancing as well as chronic musculoskeletal pain and an increased risk of falling.
In addition to these four cardinal motor symptoms, PWPD also experience deficits with systems of balance, including reactive balance, stability in gait, and transitions. The balance deficits seen in PD really increases the risk for debilitating falls. Gait is also generally negatively impacted in PD. Specifically, gait changes noted in PWPD include decreased stride length, decreased walking speed, and an asymmetric reduction in arm swing. Another clinical feature associated with gait in PD is known as freezing gait, which is a phenomenon described as a brief absence or reduction in forward progression of the feet, despite there being an intention to walk. Transfers, or moving from one position to another, such as sitting to standing, is also typically affected in PD, where PWPD show a functional decline in transfer ability, e.g. getting in/out of a car, or getting on/off a toilet. PWPD also can develop a fear of falling (FoF), which can lead to reduced participation in life and recreation.
Pretty much any muscle in the body can be affected by PD; this includes the larger muscles, such as legs, arms, and core, but also the smaller muscles associated with speech, facial expressions, and swallowing. Deficits with the smaller muscles for speaking and swallowing can lead to a very quiet and monotone vocal quality, flat affect (i.e. diminished facial expressions), and swallowing disorders. In fact, these aforementioned areas are exactly what I work to rehab, restore, and maintain in my speech therapy patients.
Nonmotor Symptoms
Accompanying the motor symptoms described above are the nonmotor symptoms of PD, which have an immense impact on QOL for those with PD. The nonmotor symptoms include manifestations with psychological issues, cognitive impairment, sleep disturbances, autonomic dysfunction, chronic pain, and loss of smell.
The most common psychological issues that occur with PD are depression and anxiety, where about half of PWPD experience one, or both, of these. Depression seems to be the most common psychological comorbidity with PD. It is unclear if the depression and anxiety seen in PWPD is a direct consequence of the pathology of the disease itself (to be discussed in more detail in part II of this series) or the psychological aspect of dealing with receiving the diagnosis itself. But, my hypothesis is that it is probably a combination of the two. I have heard many of my patients with PD say that it took them years before they could actually utter the words aloud that they have PD. And rightfully so, as receiving a diagnosis of any neurodegenerative disorder would rock anyone’s world.
Cognitive impairment is also commonly seen with PD. Indeed, about 50% of those with PD receive a diagnosis of dementia within 10 years of being diagnosed with PD. Cognitive deficits in PD can range from mild to severe, affecting memory, attention, problem solving, and executive functioning skills (e.g. planning, sequencing, organizing). Personally, as a speech therapist, I work quite frequently with cognitive deficits in my patients. I work with some patients with PD who have significant cognitive decline, some with mild-moderate cognitive deficits, and some without any cognitive impairment at all. So, this really just varies from person to person, at least in my experience.
Sleep dysfunction is another common nonmotor symptom in PD, affecting up to 98% of patients. PWPD experience a wide range of sleep disorders, including insomnia, excessive daytime sleepiness, restless leg syndrome, and REM-sleep behavior disorder (RBD). RBD includes movement during sleep such as kicking, punching, arm-flailing in response to violent dreams, and it also includes noises such as talking, laughing, or shouting. RBD can also be very challenging for spouses, caregivers, and family members who are often kept awake at night with these RBD actions.
PWPD can also experience autonomic dysfunction, where the autonomic nervous system shows evidence of deficits. The autonomic nervous system is responsible for controlling involuntary actions in the body, such as digestion, heart rate, and breathing (click here to read more about the autonomic nervous system). In PWPD, autonomic deficits can include dysregulation and issues in the cardiovascular (altered or irregular heart rate), gastrointestinal (i.e. altered or irregular digestion), urinary (altered or irregular voiding of bladder and/or bowels), and thermoregulatory systems (altered or irregular temperature regulation).
Another relatively common nonmotor symptom of PD is hyposmia, which is a decreased sense of smell. In fact, I have worked with some PWPD for whom loss of smell was the first symptom they experienced before receiving their diagnosis. Now, you might wonder if hyposmia can affect a person’s ability to taste, as the majority of taste is driven by smell, but for those I treat with PD, the loss of smell does not seem to affect their sense of taste all that remarkably. This is likely because the olfactory cortex (i.e. the part of the brain that processes sense of smell) is very close to the part of the brain where PD pathology resides; thus, the hyposmia in PD is based in the central nervous system versus the nose, where a lack of smell, such as from congestion when sick, can absolutely affect your ability to taste.
Finally, one of the most common non-motor symptoms of PD is chronic pain, but unfortunately, this is often the most under-treated and under-discussed symptom by health care providers. But, just like any other PD symptom, the presentation of pain in PD is greatly varied in type and severity, with some patients reporting no pain and others experiencing several modalities of pain, ranging from minor to severe.
The most common form of pain reported by those with PD is of musculoskeletal origin (i.e. originating in the muscles, ligaments, tendons, or bones). About 45-90% of patients with PD report musculoskeletal pain, which generally arises as a result of the postural changes and muscular rigidity seen in PD. Common conditions seen in PD include frozen shoulder (i.e. a gradual decrease in ROM in the shoulder joint with potential atrophy of the infraspinatus muscle – click here to read more about this rotator cuff muscle), low back pain, arthritis, and osteoporosis. Low back pain (click here to read more about low back pain) is generally the most common site of pain reported by those with PD, with joint pain coming in as the number two cause for pain. Loss of bone density is also common in PD, possibly due to immobility, decreased strength and weight, or even side effects from medications used to treat PD (more on this in part II of this series).
Other types of chronic pain reported by those with PD include dystonia, nerve pain, akathisia, and gastrointestinal (GI) pain. Dystonia is an uncontrolled muscle contraction accompanied by a deformed posture, usually in the hands or feet of PWPD. This can impair tasks like walking or wearing shoes, depending on the nature of the postural deformation. Nerve pain can feel like tingling, numbness, unexplainable stabbing, burning or scalding sensations and is typically caused or exacerbated by postural changes and bone deformities seen in PD. Akathisia refers to an unpleasant agitating sensation, usually in the form of restlessness or an inability to sit still, and this can cause, or exacerbate, sleep dysfunction in PD. Lastly, GI pain can be the result of a myriad of factors including, dysphagia (swallowing disorders – my area of expertise as a speech therapist), constipation, impaired gastric (i.e. stomach) emptying, and problematic absorption of nutrients.
Summary
Phew! That was a lot of information, so thank you for sticking with me until the end. And keep coming back because for the next several months, I will be releasing more information about PD. In the next installment of this series, I will go over the pathology, risk factors, and general treatment strategies for PD. In part III, I will go over what the research has shown about yoga’s effect on the motor and nonmotor symptoms of PD (spoiler alert – yoga helps; it absolutely helps, but more to come on this later). In part IV, I will go over what the research suggests about other forms of physical activity and the effects therein on PD symptoms (another spoiler alert – physical activity of any kind seems to absolutely help). Finally, in part V of this series, I will get super neuroscience-y (hey, that was my first Master’s degree, so I get to nerd-out a bit…), and go over the neuroscience of the parts of the brain affected by PD.
PD is the second most common neurodegenerative disease, second only to Alzheimer’s disease. PD is typically diagnosed in older individuals, and the rates seem to be increasing. PD results in clinical manifestations in both motor and nonmotor domains. Motor deficits typically seen in those with PD include the four cardinal signs (i.e. bradykinesia, postural instability, resting tremor, and muscular rigidity), plus issues with walking and balance and increased risk of falling. The motor deficits can impact virtually any muscle in the body, including the face, arms, mouth, legs, etc. The nonmotor deficits in PD are varied and include psychological disorders (anxiety and depression being the most common), cognitive impairment, sleep dysfunction, autonomic nervous system dysfunction, loss of smell, and chronic pain.
The symptoms seen in PD can be very debilitating and can significantly reduce QOL. While there are some pharmacological treatments that exist for PD, they typically target the motor deficits only, and even then, there are issues and side effects. Thus, there is a great need to find interventions that can help both the motor and nonmotor presentations of PD, and that is where yoga and physical activity can play a large role. I am super excited to share what the research suggests on these topics over the course of this series. Stay tuned over the next several months because the information presented in this blog series is an objective analysis of what the data seems to suggest is true. And, spoiler, it seems that the sooner a PWPD begins physical activity routines, the better the prognosis of the disease course. Please share this information with anyone you think may benefit. Thank you so much for reading part I of this series. I look forward to journeying with you over the next four months. See you next month for part II of this blog series.
As always, the information presented in this blog post is derived from my own study of human movement, anatomy and physiology, yoga, and neuroscience. If you have questions about Parkinson's disease specific for you, please follow up with your physician, neurologist, or physical therapist. If you are interested in private yoga and/or personal training sessions with me, Jackie, email me at info@lotusyogisbyjackie.com for more information about my services. Also, please subscribe to my website so you can receive my monthly newsletters (scroll to the bottom of the page where you can submit your email address). This will help keep you "in-the-know" about my latest blog releases and other helpful yoga and wellness information. Thanks for reading!
~Namaste, Jackie Allen, M.S., M.Ed., CCC-SLP, RYT-200, RCYT, NASM-CPT, NASM-CES, NASM-CNC, NASM-SFC, NASM-WLS
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