Head Tremors Linked to Parkinson’s Severity in Small Study
Greater head motions due to Parkinson’s-related tremors were found to be associated with worse disease severity, a small study in patients reported.
As an added diagnostic test in the clinic, measuring the degree of tremors affecting the head may also help in recognizing Parkinson’s early in people, its researchers said.
The study, “Correlation between head tremble and the severity of Parkinson’s disease,” was published in the journal CNS Neuroscience & Therapeutics.
Tremors, muscle rigidity, and abnormally slow movements (bradykinesia) are characteristic motor symptoms of Parkinson’s disease. Patients also often have problems with balance and walking, with a tendency for a shuffling gait with a lack of arm swinging and rigidity. Head shaking is another specific motor symptom.
As Parkinson’s progresses, problems with speech typically arise, including a hoarse and weak voice. Speech assessments have also identified a greater range of head movements, or shaking, in patients than in people without this disease.
However, few studies have examined the relationship between early head shaking and Parkinson’s severity.
A study designed by scientists at the Beijing Institute of Basic Medical Sciences in China assessed the correlation between head shaking during a clinical speech assessment and disease severity.
“This study aimed to decipher an accurate degree of head-shaking to help the early recognition of [Parkinson’s disease] as an auxiliary diagnosis in the clinic,” the team wrote.
It enrolled 18 people with Parkinson’s who had been admitted to the Neurology Department of the First Affiliated Hospital of Chengdu Medical College. Their mean age was 72.7, the mean disease duration was about five years, and half were women.
A group of 18 healthy individuals of similar age and sex was included as a control comparison. There were no significant differences between patients and controls in alcohol consumption, smoking habits, profession, and education level.
Parkinson’s severity was measured using two common assessment tools: the Hoehn-Yahr (HY) scale and the Unified Parkinson’s Disease Rating Scale (UPDRS III). The HY scale is classified from stage 1, indicating mild symptoms, to stage 5 or severe disease. The UPDRS III scale is assessed from 0, meaning no disability, to 199, reflecting total disability.
Speech was examined using a phonation test, in which the vowels “a,” “o,” and “e” were in words of one, two, or multiple syllables up to 26. At the same time, the laptop’s camera recorded head tremors and detailed facial expressions, and the data were analyzed with FaceReader software.
Head movements were measured in three dimensions: side-to-side (x-axis), up-and-down (y-axis), and forward-and-back (z-axis).
Among men given the tests, significant differences were detected in 1, 9–17, and 19–26 syllables between Parkinson’s patients and controls in tremors with a side-to-side trajectory (x-axis). With up-and-down head tremors (y-axis), significant differences were also seen in 1, 4, 6, 7, 9, 10, 12, 13, 15, 18, 20–22, and 24–26 syllables
In addition, data revealed significant differences in the 2–13, 15–21, and 24–26 syllable tests between male patients and healthy individuals in forward-and-back head tremor (z-axis).
In the single syllable test, there was a correlation between greater forward-to-back head tremors (z-axis) and HY severity in male patients. Greater head tremor in all three directions (x, y, and z) associated with HY severity in the double syllable test. Data from the multiple syllables test showed an association between increased up-and-down head tremor (y-axis) and greater HY severity.
Higher UPDRS III disability in male patients correlated with up-and-down (y-axis) and forward-and-back (z-axis) head tremors in the single, double, and multiple syllable tests.
Among women, significant differences were found between patients and controls in the 2–24 and 26 syllable tests in the side-to-side (x-axis) direction. With up-and-down tremors (y-axis), significant differences were seen in all 26 syllables. Significant differences were also found with forward-and-back (z-axis) movements in the 3–9, 12–14, 16, 19, 21–24, and 26 syllable tests.
HY severity in female patients correlated with greater up-and-down (y-axis) head tremors in the single syllable test. In the double syllable test, there was a correlation between HY severity and increased head tremor in the forward-and-back direction (z-axis). Data from the multiple syllables test showed an association between greater side-to-side (x-axis) head tremors and greater HY severity.
Higher UPDRS III disability scores in female patients correlated with tremors in all three directions in the double and multiple syllable tests, and up-and-down (y-axis) and forward-and-back (z-axis) in the single syllable test.
Generally, Parkinson’s patients had a greater range of head tremor motion from side-to-side (x-axis) compared to healthy individuals, but this correlated with less severe disease. In comparison, up-and-down (y-axis) and forward-and-back (z-axis) tremors associated with more severe disease, “which was related to muscle stiffness,” the researchers wrote.
“In the phonetic test, [Parkinson’s disease] patients showed typical displacement compared with normal individuals, and the displacement amplitude [range] was positively correlated with the severity of the disease,” the scientists concluded. “This study determined an accurate degree of cranial tremor, which is valuable for the early detection of [Parkinson’s disease].”