Parkinson’s and Trauma Part 1: Can Injury Trigger Onset? 87 Cases and a New Survey

Among the most striking studies I’ve uncovered is a series of observations about trauma before the onset of Parkinson’s disease (PD). I found these 25 years ago when I first began to explore whether adverse experiences might be a risk factor for chronic illness. A large number of case reports described how the first symptoms of Parkinson’s disease began after trauma to a limb. Even more significant was that PD onset after injury often began in the limb that had been physically harmed.

The story that emerged from published journal articles was that trauma was considered a risk factor for Parkinson’s disease from the very beginning in 1817 when symptoms were first described as a distinct condition ⁽¹⁾Slater, M. J. (2000, Vancouver, BC). Parkinsonism and Traumatic Brain Injury. The Verdict(TBI Update), 31-38. Interest in the role of trauma then waned, recurred in the early 1900s when legislation was introduced to support injured workers with compensation, and waned again when none of the theories about mechanisms seemed to be able to fit the histories doctors were encountering. The possible role of trauma in triggering the onset of Parkinson’s disease, or as a possible risk factor for PD in general, is rarely mentioned in present day medical care.

Today’s post introduces case reports and the updated science of trauma to shed new light on the role of trauma in Parkinson’s disease.

I’ll share an article from New York neurologist Dr. L. Grimberg, who reviewed 86 cases in 1934 ⁽²⁾Grimberg, L. (1934). Paralysis agitans and trauma. J Nerv & Ment Dis, 79, 14-43. Another case I’ll share today was cited by lawyer Michael J. Slater in 2000 in a report from the physician whose name was eventually used for this chronic illness, Dr. James Parkinson ⁽³⁾Slater, M. J. (2000, Vancouver, BC). Parkinsonism and Traumatic Brain Injury. The Verdict(TBI Update), 31-38.

You can download a free PDF of this blog post at the bottom of this page.

A note about the images in this post. I frequently use an animal or other symbol to represent a chronic illness as a gentle way to accompany posts. It is also a metaphor for the possibility that symptoms may reflect intelligent adaptations in the wild animals. I use the sloth as a symbol for Parkinson’s disease. This is not because people with PD are lazy (far from it) but because sloths move very slowly as part of a highly successful adaptation. This slowed pace is similar to one of the predominant symptoms of Parkinson’s known as “bradykinesia,” or slowed movement. For people with PD, this slowed movement can make activities of daily living much more difficult, such as for the processes of rising from a chair, dressing, writing, walking and much more. See my posts on bears in hibernation as a symbol for diseases associated with insulin resistance and chronic fatigue syndrome.

1. Is Trauma a Risk Factor for Parkinson’s Disease?

The idea that trauma can have a bearing on the occurrence of Parkinson’s disease is rooted in the history of medicine.

This suggested relationship dates back to the first description of the condition as a separate entity in 1817 by the eminent London physician, Dr. James Parkinson (Slater, “Parkinsonism and Traumatic Brain Injury.” in “The Verdict,” a legal journal of the nonprofit organization Trial Lawyers Association of British Columbia (TLABC). (2000) ⁽⁴⁾Slater, M. J. (2000, Vancouver, BC). Parkinsonism and Traumatic Brain Injury. The Verdict(TBI Update), 31-38.

2. Example 1: The Count de Lordat

In his “Essay on the Shaking Palsy,” Parkinson coined the Latin phrase “paralysis agitans” to describe the onset of a set of symptoms in his patient the Count de Lordat, who had been injured when his coach overturned. In the accident the patient struck his head and suffered bruising to his left shoulder, arm and left hand. Symptoms of the disease were first reported one year later when the patient noticed rigidity in his left arm (Slater, 2000) ⁽⁵⁾Slater, M. J. (2000, Vancouver, BC). Parkinsonism and Traumatic Brain Injury. The Verdict(TBI Update), 31-38.

Trauma as a Cause of PD Lost Favor in the Early 1900s

For 50 years in the 1800s, peripheral trauma was considered to be a risk factor for Parkinson’s, including observations by the renowned French neurologist, Pierre Marie Charcot, who renamed “paralsysis agitans” as “Parkinson’s disease” (Slater, p. 31). Charcot believed that if trauma was involved, the site of the injury would also be the location of the first observable symptoms of Parkinson’s. Not long afterwards, however, the predominant view of trauma and PD changed into the perspective that persists today, which is that trauma only causes PD if physical harm directly impacts the deep centers of the brain associated with Parkinson’s.

One influence on this change in the predominant view came about when no significant increases in Parkinson’s disease were observed during or following the trauma of World War I (Chand, 1985; Grimberg, 1934; Slater, 2000) ⁽⁶⁾Chand, P. (1985). Post traumatic Parkinsonian syndrome: A case report. Medical Journal of Malaysia, 40(4), 335-337, ⁽⁷⁾Grimberg, L. (1934). Paralysis agitans and trauma. J Nerv & Ment Dis, 79, 14-43, ⁽⁸⁾Slater, M. J. (2000, Vancouver, BC). Parkinsonism and Traumatic Brain Injury. The Verdict(TBI Update), 31-38. A second influence was the emerging split between mind and body. About 100 years ago medicine started to consider that physical symptoms were linked specifically to the anatomical regions of the physical body they corresponded with, such as the brain in PD and the pancreas in type 1 diabetes. Emotional and mental symptoms were separated into the distinctly separate realm of the mind (Joslin, 1943) ⁽⁹⁾Joslin, E. P. (1943, Apr). The Relation of Trauma to Diabetes. Annals of Surgery, 117(4), 607-622.

I had never learned any of this history in my medical training.

What follows comes from a detailed case report with 86 examples of trauma preceding the onset of Parkinson’s disease: cases of PD onset after injury.

3. Example 2: 86 Case Reports of PD Onset after Injury

In 1934 Grimberg, the neurologist cited above in the legal paper by Slater (2000), reviewed 86 case reports published between 1873 and 1934. Reports were of individuals who had developed symptoms of possible Parkinson’s after an injury. Grimberg stated at the beginning of his review that, “Many of the authors were of such outstanding professional qualifications that their cases had to be considered” (p. 14).

Among the 86 cases, 50 cases (58%) were of people who experienced traumatic injuries to a limb. Injuries included burns, fractures, dislocations and contusions. The remaining 36 cases were due to injuries to the head or other parts of the body from falls, accidents, being hit, thrown or run over. A few cases were from non physical stressors such as stress at work or, in two cases, the stress of having gotten very cold after a fall in the snow.

After a thorough review and description of each case in his paper, Grimberg dismissed all 86 cases. His final conclusion was that, “Trauma cannot cause Paralysis Agitans.”

Below are some of the reasons Grimberg described, which are also common reasons for eliminating trauma as a risk factor for Parkinson’s disease in present day.

4. Grimberg’s 12 reasons for dismissing trauma

The biggest issue described by Grimberg in reviewing the 86 case reports was the challenge of identifying a mechanism by which an injury could lead to a chronic, usually progressive, central nervous system disease. It was especially difficult to explain connections to symptoms that began in a part of the body that had not been harmed by physical trauma.

The following list describes 12 of the reasons Grimberg, and other colleagues, presented for dismissing the role of trauma as a potential risk factor or onset trigger for Parkinson’s disease in the 1930s:

1. Onset was more than 1 year after the injury
2. Onset was in a limb or body part that was not injured
3. History of timing was vague, such as when obtained 2 or more years after onset of symptoms
4. Other factors existed that might cause symptoms, such as alcoholism
5. Having had influenza prior to the injury
6. The wound was small
7. There was no head trauma
8. The head trauma was not severe
9. Multiple traumas occurred and symptoms began after the 2nd, milder trauma
10. There were too many mental changes
11. The injury accelerated or aggravated existing PD, meaning the traumatic event reported did not cause Parkinson’s
12. The tremor or other symptoms stabilized or did not progress after onset

The perspective at the time was evolving into the view that predominates today, which is that for trauma to play a role in the onset of Parkinson’s it must be:

• physical trauma
• severe trauma
• cause direct damage to the brain
• occur 1 year or less before the onset of the first symptom of PD

5. Trauma Science Offers Insights into Grimberg’s Cases

The science of trauma has evolved in the past 100 years to shed light and provide insights for different interpretations of Grimberg’s 86 cases.

Neurologist, traumatologist and director of a rehabilitation medicine clinic Dr. Robert Scaer wrote extensively on the neuroscience of trauma, including onset and progression of symptoms after physical or emotional trauma. One of Scaer’s specialties was in the assessment of symptoms following motor vehicle accidents. His work provides an in-depth, highly referenced source for the perspectives I present below (an article (2001a) ⁽¹⁰⁾Scaer, R. C. (2001). The neurophysiology of dissociation and chronic disease. Applied Psychophysiology and Biofeedback, 26(1), 73-91; and a book (2001b) ⁽¹¹⁾Scaer, R. C. (2001). The Body Bears the Burden: Trauma, dissociation, and disease. Haworth Medical, The Body Bears the Burden downloadable as a free PDF for members of the free Academia.edu (you can sign up for free). See especially Scaer’s book chapter 8 about symptoms following accidents and other traumatic events, including when no physical injury occurs. Dr. Scaer and I were in a peer supervision group together when I worked as a trauma therapist and we had similar points of view. The following references provide additional support from the trauma literature: van der Kolk, 1996 ⁽¹²⁾van der Kolk, B. A., McFarlane, A. C., & Weisaeth, L. (Eds.). (1996). Traumatic stress: The effects of overwhelming experience on mind, body, and society. Guilford, 2014 ⁽¹³⁾van der Kolk, B. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma (1st ed.). Viking; Levine, 1997 ⁽¹⁴⁾Levine, P. (1997). Waking the tiger: Healing trauma. North Atlantic Books, 2010 ⁽¹⁵⁾Levine, P. (2010). In an unspoken voice: How the body releases trauma and restores goodness. North Atlantic; Mate, 2003 ⁽¹⁶⁾Mate, G. (2003). When the body says no: Understanding the stress-disease connection. Wiley & Sons, 2023 ⁽¹⁷⁾Mate, G., & with Mate, D. (2023). The Myth of Normal: Trauma, Illness, and Healing in a Toxic Culture. Avery; Miller, 2008 (trauma and PD) ⁽¹⁸⁾Miller, D. B., & O’Callaghan, J. P. (2008, Oct). Do early-life insults contribute to the late-life development of Parkinson and Alzheimer diseases? Metabolism: Clinical and Experimental, 57 Suppl 2, S44-49; Rice, 2000 ⁽¹⁹⁾Rice, D., & Barone, S., Jr. (2000, Jun). Critical periods of vulnerability for the developing nervous system: Evidence from humans and animal models. Environmental Health Perspectives, 108 Suppl 3, 511-533; Yehuda, 2015 ⁽²⁰⁾Yehuda, R., Hoge, C. W., McFarlane, A. C., Vermetten, E., Lanius, R. A., Nievergelt, C. M., Hobfoll, S. E., Koenen, K. C., Neylan, T. C., & Hyman, S. E. (2015, 10/08/online). Post-traumatic stress disorder [Primer]. Nat Rev Dis Primers, October, 150-157, and most recently The Biology of Trauma, by Dr. Aimie Apigian (2025) ⁽²¹⁾Apigian, A. (2025). The biology of trauma: How the body holds fear, pain, and overwhelm, and how to heal it. BenBella Books.

Defining Trauma

Trauma can be defined as an experience that is perceived to be both life-threatening and inescapable, regardless of whether one’s life is actually at risk. For example, a person can have an experience that is emotionally traumatic even if no physical injury occurs, such as from witnessing a violent death, being routinely locked in a closet as a child, or from childhood emotional neglect.

Trauma symptoms occur when an event triggers “Freeze”

What makes something traumatizing is the overwhelming nature of being unable to successfully overcome the situation, such as by fighting one’s way through or fleeing from harm. Such experiences can lead to unconscious, involuntary nervous system responses of “freeze” and shut down. The state of freeze suppresses the motor and other impulses, such as those embedded in the punch that didn’t happen, the hands that could not turn the steering wheel fast enough to avoid collision, the bracing in the trunk that could not prevent a fall, or the withdrawal impulse in the leg that could not avoid being run over.

Trauma symptoms arise from freeze or suppressed fight or flight

In trauma and freeze, the brain and nervous system retain the state of the highly charged but suppressed impulse of fight and flight. This might involve the impulse to complete the punch, turn the steering wheel to the right, brace the neck to protect one’s head during the fall, or withdraw the left leg to avoid being crushed by the carriage. The impulse gets frozen in time but not forgotten. Until that impulse is completed or dismissed in some way, the brain does not receive the message that it has survived the assault, the accident, or the fall. Healing trauma involves various approaches that help process the suppressed states of heightened sympathetic nervous system charge, such as through following a subconscious impulse for a particular movement, experiences of discharge while in a state of the present moment, such as through the body’s unconscious process of trembling or shaking, and other means. Early developmental trauma may cause states of pure shutdown without underlying fight and flight, which can also be worked with.

Might tremor and rigidity in Parkinson’s reflect a trauma response?

From a trauma perspective, the tremor or rigidity that begins in a limb after an injury could reflect a state of frozen, truncated movement held at bay in the circuitry of the brain as well as within the muscles and nerves conducting messages in the affected limb. Through processes referred to in the field of trauma as “kindling,” (Scaer, 2001a,b) a state of freeze can spread to include other parts of the body that were not physically injured, such as the shoulder that braced when the forearm was crushed or the arm that held onto the carriage door when the leg was injured. Ultimately, trauma does not need to be physical or have direct impact on the brain or other specific part of the body to cause physical and physiological changes that lead to symptoms (see Scaer’s 2001 book, chapter 8 for detailed examples ⁽²²⁾Scaer, R. C. (2001). The Body Bears the Burden: Trauma, dissociation, and disease. Haworth Medical.

6. 12 Patterns in Trauma Science Address Concerns About Adversity as a Risk Factor for PD

Trauma science provides mechanisms that can explain what was not known 100 years ago when Grimberg and colleagues were trying to make sense of symptoms and PD onset after injury ⁽²³⁾Grimberg, L. (1934). Paralysis agitans and trauma. J Nerv & Ment Dis, 79, 14-43. The resources cited in the previous section provide options for a more detailed and nuanced foundation on trauma. You are welcome to email me if you’d like a copy of any of the resources cited in this post.

Common Patterns in Trauma

1. Onset after a traumatic event is variable and can be more than 1 year
2. Symptom location can be in uninjured parts of the body influenced by
   • past trauma or injury
   • secondary events such as bracing far from the site of the injury
3. Symptoms sometimes tell the story even if history is vague. Grimberg describes one man (case 85) who had fallen off a roof and whose posture, years later, “was that of a man climbing a roof.” This could refer to the forward-leaning posture often associated with PD, but might be related to this man’s particular traumatic experience, suggestive of a body frozen in time
4. Overuse of alcohol and other substances suggests prior trauma (ie: ACEs)
   • Adverse childhood experiences (ACEs) are a risk factor for PD (Subramanian et al, 2023) ⁽²⁴⁾Subramanian, I., McDaniels, B., Farahnik, J., & Mischley, L. K. (2023, Apr). Childhood Trauma and Parkinson Disease: Associations of Adverse Childhood Experiences, Disease Severity, and Quality of Life. Neurol Clin Pract, 13(2), e200124
5. Infections
   • do not preclude trauma affecting risk for PD onset after injury
   • trigger onset of many chronic diseases that are affected by trauma
   • may be a form of overwhelming threat stimulating a cell danger response Naviaux 2014 ⁽²⁵⁾Naviaux, R. K. (2014, May). Metabolic features of the cell danger response. Mitochondrion, 16, 7-17, 2018 ⁽²⁶⁾Naviaux, R. (2018, May). Metabolic features and regulation of the healing cycle—A new model for chronic disease pathogenesis and treatment. Mitochondrion, 46, 278-297
6. Effects of trauma are influenced by perception of threat, not just injury
7. Psychological trauma can cause symptoms without physical or head trauma
8. Head trauma can be associated with trauma-related symptoms even if not severe
9. Multiple traumas are referred to as “multiple hits” (Vlajinac, 2013)⁽²⁷⁾Vlajinac, H., Sipetic, S., Marinkovic, J., Ratkov, I., Maksimovic, J., Dzoljic, E., & Kostic, V. (2013, Feb). The stressful life events and Parkinson’s disease: a case-control study [Research Support, Non-U.S. Gov’t]. Stress Health, 29(1), 50-55
   • prior trauma may initiate a process that is unmasked by later trauma before onset (Miller, 2008; Rice, 2000; van der Kolk, 1996)
10. Mental and emotional changes can result from trauma, as seen in PTSD
11. Trauma can accelerate or aggravate existing symptoms of a chronic illness
12. Rates of progression of trauma symptoms are influenced by past trauma, perceived severity of events, experiences going forward, and more …

7. Grimberg’s 86 Case Reports Offer 3 More Indicators for the Role of Trauma

In reviewing Grimberg’s descriptions of each of the 86 cases, a few characteristics suggestive of a role for trauma in triggering onset of PD are especially significant. I calculated the percentages in #2 and #3 below based on the detailed descriptions of the cases.

1. Cases Likely Traumatic. Most of Grimberg’s cases may have been emotionally traumatic even if the injury was mild or there was no physical injury. Others appear overtly traumatic such as falling 75 feet down a mine shaft, 15 feet off a roof, being run over by a carriage
2. 88% PD Onset was in Injured Limb. 50 of the 86 cases involved injuries to a limb. In 2 of these cases the site of onset of PD symptoms was not known, bringing the total cases of injuries to a limb with complete information to 48. In 40 of these 48 cases (88%), symptoms began in the injured limb. This is a remarkable percentage of cases supporting the role of trauma affecting onset.
3. 93% of PD Onset after Mild Injuries was in Injured Limb. 14 cases were dismissed because the injury was considered too mild. 13 (93%) of these cases were associated with onset in the limb that had been injured. This could indicate that the events had a psychologically traumatic component or were not the first trauma to the limb. They support a role of trauma in PD onset.

8. Conclusion to Part I: Injuries can Trigger PD Onset

The research suggests that trauma, whether a physical injury or a psychologically traumatic event, is associated with the onset of Parkinson’s disease. The science suggests that trauma can trigger the emergence of tremors, rigidity and progression to the onset of the diagnosable condition of PD. Additional cases of PD onset after injury have been reported in the literature (Naville, 1932 ⁽²⁸⁾Naville, F., & De Morsier, G. (1932). Title not known [Abstract]. Ann Med Leg, 12, 165; Hodgson, 1937 ⁽²⁹⁾Hodgson, J. C. (1937, Sept). Parkinsonism following peripheral trauma [1]. BMJ, 2, 581; Walker, 1937 ⁽³⁰⁾Walker, G. F. (1937, July). Parkinsonism following peripheral trauma. BMJ, 2, 65; Weinberg, 1939 ⁽³¹⁾Weinberg, M. H. (1939). Two cases of Parkinson’s syndrome resulting from electrical injury. The Journal of Nervous and Mental Disease, 90(6), 738-746; Chand, 1985 ⁽³²⁾Chand, P. (1985). Post traumatic Parkinsonian syndrome: A case report. Medical Journal of Malaysia, 40(4), 335-337; Schwab & England, 1975 ⁽³³⁾Schwab R S, E. A. C. (1975). Parkinson syndromes due to various specific causes. In B. G. W. Vinken P J (Ed.), Handbook of Clinical Neurology (Vol. 6, pp. 227-247). North Holland Publishing Company; Tekin, 2015⁽³⁴⁾Tekin, I., Vgontzas, A., Lewis, M. M., Kothari, S., Kong, L., Lu, Y., Vrana, K. E., & Huang, X. (2015, Jul). Previous Injury and Chronic Pain are Associated with Side of Onset in Parkinson’s Disease. J Neurol Neurobiol, 1(3).

I have coined the term “Adverse Pre-Onset Experiences” or “APOEs,” drawing on the terminology used for Adverse Childhood Experiences (ACEs). APOEs refer to the role of adversity that can trigger onset of a chronic health condition.

APOEs are a phenomenon seen in other chronic diseases, including:

• inflammatory bowel disease (Hollander, 2003) ⁽³⁵⁾Hollander, D. (2003, Dec). Inflammatory bowel diseases and brain-gut axis. Journal of Physiology and Pharmacology, 54 Suppl 4, 183-190
• multiple sclerosis (Warren et al, 1982) ⁽³⁶⁾Warren, S. A., Warren, K. G., Greenhill, S., & Paterson, M. (1982). How multiple sclerosis is related to animal illness, stress and diabetes. Canadian Medical Association Journal, 126(4), 377-382, 385
• rheumatoid arthritis (Al-Allaf et al, 2001) ⁽³⁷⁾Al-Allaf, A. W., Sanders, P. A., Ogston, S. A., & Marks, J. S. (2001, Mar). A case-control study examining the role of physical trauma in the onset of rheumatoid arthritis. Rheumatology (Oxford, England), 40(3), 262-266
• type 1 diabetes (Dalhquist, 1991 ⁽³⁸⁾Dahlquist, G., Blom, L., & Lonnberg, G. (1991, Oct). The Swedish Childhood Diabetes Study: a multivariate analysis of risk determinants for diabetes in different age groups. Diabetologia, 34(10), 757-762; Renzaho, 2014 ⁽³⁹⁾Renzaho, A. M., Houng, B., Oldroyd, J., Nicholson, J. M., D’Esposito, F., & Oldenburg, B. (2014, Feb). Stressful life events and the onset of chronic diseases among Australian adults: Findings from a longitudinal survey. European Journal of Public Health, 24(1), 57-62
• fibromylagia (Clauw, 2001) ⁽⁴⁰⁾Clauw, D. J. (2001). Potential mechanisms in chemical intolerance and related conditions. Annals of the New York Academy of Sciences, 933, 235-253
• learn more in this blog post

Whether trauma before onset can initiate the onset of Parkinson’s disease or unmasks a condition that has been brewing is not clear. Also, this does not mean that having an injury or other traumatic experience implies that someone will develop Parkinson’s or some other chronic condition. I will share additional research on the role of trauma in PD in a future blog post.

9. Why It Matters if Trauma is a Risk Factor

The reason to consider the role of trauma in Parkinson’s disease and other chronic conditions is that it may be possible to treat symptoms of trauma, thus offering another tool and approach that supports living with, managing and working with symptoms. Treating trauma early may be able to reduce risk or prevent onset, delay onset, or reduce severity of symptoms.

Tools, perspectives and approaches exist that can be helpful for healing trauma. Perhaps such tools can be helpful for people with PD or who are at risk of developing PD. This may be an avenue to explore if you have PD or have experienced trauma and live with a different chronic health condition. See links to resources below for more information.

Resources

Trauma and Chronic Illness: 19 Characteristics that Can Make Sense of Symptoms (Summary of the Science)

16 Trauma Informed Tools for Healing Chronic Illness and Addressing Nervous System Perceptions of Threat

Tips for Working with Symptoms

Therapies for Working with Trauma and Directories to Find a Therapist

10. Take the Adverse Pre-Onset Experiences Survey (for anyone with any chronic symptom)

Do the stories in today’s post resonate with you? Did something happen before the onset of your chronic condition that felt like it may have caused it or triggered onset?

I am interested in hearing about your experiences as I continue to learn, explore and delve into the research about trauma as a risk factor for chronic health conditions.

This is the first draft of a survey on Adverse Pre-Onset Experiences (APOEs).

• It is for any adult
• Anyone with a chronic physical or mental health condition
• Anyone with a chronic illness, chronic pain or a other chronic symptom even if it has no name.
• Your responses will help with understanding this complex phenomenon.
• Your input will also help make this survey better going forward.

Please take the survey, leave a comment, share your story below or email me directly here.

11. Download this post as a Free PDF