Brain Ultrasound Signals Linked to Motor Disability, Gait
Transcranial sonography may help measure disease severity
Enhanced ultrasound signals in the substantia nigra, the area of the brain impacted by Parkinson’s disease, are associated with increased motor disability and gait disturbances, a study concluded.
The researchers noted that these ultrasound signals, called hyperechogenicity, may be useful a biomarker that reflects disease severity.
“Our results may aid the management of [Parkinson’s disease] patients and enhance individualized care for these patients,” the researchers wrote.
The ultrasound study, “Clinical Features in Parkinson’s Disease Patients with Hyperechogenicity in Substantia Nigra: A Cross-Sectional Study,” was published in the journal Neuropsychiatric Disease and Treatment.
Parkinson’s disease is marked by the loss of nerve cells in the part of the brain called the substantia nigra, which leads to characteristic motor and non-motor symptoms.
Transcranial sonography (TCS), or ultrasound, is a non-invasive diagnostic technique that can reveal structural changes in the brain. Enhanced TCS signals known as hyperechogenicity have been detected in the substantia nigra of people with Parkinson’s.
However, whether TCS can be used as a biomarker to measure disease severity is unknown.
To determine the value of this technique, 75 people with Parkinson’s were examined by researchers based at the Affiliated Brain Hospital of Nanjing Medical University in China.
Participants underwent TCS of the substantia nigra alongside standard clinical assessments.
The team also conducted a series of gait measures, including stride length, time, gait velocity, and cadence. The range of motion of the hip, knee, and ankle joints was measured, plus the toe-off and heel strike angles. All participants were asked to stop Parkinson’s medication 24 to 72 hours before the gait assessments.
Based on TSC results, the team divided participants into two groups: those with, and those without, hyperechogenicity in their substantia nigra. There were no significant differences in age, sex, height, or weight between the two groups.
Compared to patients without enhanced TCS signals, those with hyperechogenicity had significantly higher (worse) motor symptom scores (12.61 vs. 15.65) based on the Unified Parkinson’s Disease Rating Scale (UPDRS) part 2, a standard assessment of daily motor disability.
Statistical analysis confirmed a significant correlation between higher UPDRS part 2 scores and hyperechogenicity.
There were, however, no significant differences between the two groups related to nonmotor symptoms, which included cognitive function, sleep quality, depression, anxiety, and quality of life.
Focus on gait
Focusing on gait parameters, the team found a significant positive association between hyperechogenicity and increased variability in the length of the stride.
There was also a significant difference between patients with and without substantia nigra hyperechogenicity in hip joint range of motion and heel strike angle, the angle between the foot and ground when the heel strikes. Hyperechogenicity was significantly and negatively correlated with a smaller range of hip motion and reduced heel strike angle.
Last, there was a significant increase in the asymmetry of the ankle joint range of motion in those with hyperechogenicity, which was confirmed by correlational analysis.
The researchers noted that the association between gait disturbance and hyperechogenicity might explain the higher UPDRS part 2 scores.
“Our study demonstrated that [substantia nigra hyperechogenicity] significantly correlated with activities of daily living and gait impairment in Chinese patients with [Parkinson’s disease], suggesting the formation of [hyperechogenicity] might be a dynamic biomarker reflecting disease severity,” the researchers concluded.
“Follow-up studies could explore the development of more individualized treatment or rehabilitation plans for [Parkinson’s disease] patients with [substantia nigra hyperechogenicity],” they added.
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