The characteristic and biomarker value of transcranial sonography in cerebellar ataxia

OBJECTIVE

Transcranial sonography (TCS) is a noninvasive neuroimaging technique, visualizing deep brain structures and the ventricular system. Although widely employed in diagnosing various movement disorders, such as Parkinson's disease and dystonia, by detecting disease-specific abnormalities, the specific characteristics of the TCS in cerebellar ataxia remain inconclusive. We aimed to assess the potential value of TCS in patients with cerebellar ataxias for disease diagnosis and severity assessment.

METHODS

TCS on patients with genetic and acquired cerebellar ataxia, including 94 with spinocerebellar ataxias (SCAs) containing 10 asymptomatic carriers, 95 with cerebellar subtype of multiple system atrophy (MSA-C), and 100 healthy controls (HC), was conducted. Assessments included third ventricle width, substantia nigra (SN) and lentiform nucleus (LN) echogenicity, along with comprehensive clinical evaluations and genetic testing.

RESULTS

The study revealed significant TCS abnormalities in patients with cerebellar ataxia, such as enlarged third ventricle widths and elevated rates of hyperechogenic SN and LN. TCS showed high accuracy in distinguishing patients with SCA or MSA-C from HC, with an AUC of 0.870 and 0.931, respectively. TCS abnormalities aided in identifying asymptomatic SCA carriers, effectively differentiating them from HC, with an AUC of 0.725. Furthermore, third ventricle width was significantly correlated with SARA and ICARS scores in patients with SCA3 and SCOPA-AUT scores in patients with MSA-C. The SN area and SARA or ICARS scores in patients with SCA3 were also positively correlated.

INTERPRETATION

Our findings illustrate remarkable TCS abnormalities in patients with cerebellar ataxia, serving as potential biomarkers for clinical diagnosis and progression assessment.

Alterations in transcranial sonography among Huntington's disease patients with psychiatric symptoms

Transcranial sonography (TCS) is a diagnostic tool in mood and movement disorders. Alterations within the raphe mesencephalic nucleus in the brain have been reported not only in patients with major depression but in patients with depressive symptoms accompanying several neurodegenerative disorders. The aim of the study was to assess the echogenicity of the nucleus raphe and other basal ganglia in patients with Huntington’s disease (HD). TCS was performed in 127 HD patients participating in observational studies (Registry/Enroll-HD) in the Institute of Psychiatry and Neurology (Warsaw, Poland). Raphe hypoechogenicity was found in 78% of HD patients with current symptoms of depression (according to DSM-IV criteria), 57% of patients with a previous history of depression, and 56.8% patients who lacked signs or history of depression. Patients with hypoechogenic raphe reported significantly higher depression as measured on the BDI (15.6 ± 1.7) as compared to patients with normal echogenicity (9.5 ± 1.2), (p = 0.023). The diameter of the third ventricle was negatively correlated with Mini-Mental State Examination (MMSE) (rho − 0.37) and total functional capacity (TFC) scores (rho − 0.26). Hyperechogenic substantia nigra was visualized in 66,4% patients with HD and the degree of hyperechogenicity was correlated with the total motor score (TMS) (rho − 0.38). Changes in echogenicity of the basal ganglia are related to both depressive and motor symptoms among patients with HD.

Assessment of substantia nigra echogenicity in German and Filipino populations using a portable ultrasound system

OBJECTIVES

Transcranial sonography of the substantia nigra for diagnosing premotor stages of Parkinson disease has been attracting increasing interest. Standard reference values defining an abnormal increased echogenic size (hyperechogenicity) of the substantia nigra have been established in several populations using high-end stationary ultrasound systems. It is unknown whether a portable ultrasound system can be appropriately used and how the Filipino population would compare with the well-studied white population.

METHODS

We prospectively studied substantia nigra echogenic sizes and third ventricle widths in 71 healthy adult German participants and 30 age- and sex-matched Filipino participants using both a well-established stationary ultrasound system (in the German cohort) and a recently distributed portable ultrasound system (in both ethnic cohorts).

RESULTS

Mean substantia nigra echogenic sizes, cutoff values defining abnormal hyperechogenicity, and intra-rater reliability were similar with both systems and in both ethnic cohorts studied. The Filipino and German participants did not differ with respect to the frequency of insufficient insonation conditions (each 3%) and substantia nigra hyperechogenicity (10% versus 9%; P = .80). However, third ventricle widths were smaller in the Filipino than the German participants (mean ± SD, 1.6 ± 1.1 versus 2.4 ± 1.0 mm; P = .004).

CONCLUSIONS

The frequency of substantia nigra hyperechogenicity appears to be homogeneous in white and Asian populations. Screening for this feature may well be performed with a present-day portable ultrasound system.

Three-dimensional reconstruction of transcranial ultrasound images obtained through the temporal bone window using a helmet-mounted mechanical beam-steering device

Transcranial sonography has been an increasingly widespread diagnostic tool for the diagnosis of neural diseases like Parkinson's disease. However, the utilization of modern 3D ultrasound techniques has been hampered by the acoustical barrier of the skull bones. We report the development of and preliminary results from an ultrasound helmet which uses mechanical beam-steering to allow 3-D reconstruction of deep brain structures such as the substantia nigra.

Substantia nigra echogenicity in Parkinson's disease: relation to serum iron and C-reactive protein

In Parkinson's disease (PD), substantia nigra hyperechogenicity (SN-h) has been related to both, local iron accumulation and microglia activation. We analysed its relationship in PD patients with serum iron (n = 31) and C-reactive protein (CRP; n = 193). SN-h correlated with lower CRP and iron levels. Also, patients with a first-degree relative with PD had lower iron levels. Microglia activation, if reflected by SN-h, may be therefore unrelated to serum CRP. Findings support the idea that SN-h indicates inherited alteration of iron metabolism.

Essential tremor and Parkinson's disease: lack of a link

BACKGROUND

Essential tremor (ET) is a very common disorder and proving that there is a relationship to another common movement disorder, Parkinson's disease (PD), has been debated for years.

METHODS

Review of the literature for links between ET and PD primarily focused on neuropathology as well as neurochemistry, epidemiology, genetics, olfactory function, and neuroimaging.

RESULTS

While there may be some evidence to suggest an increase in occurrence of PD in people who were previously diagnosed with ET, neuropathologic studies of ET with similarly assessed control subjects do not find an increase in Lewy bodies in the ET group. Studies of incidental Lewy body disease do not find an increase in ET or action tremor compared to controls. ET subjects as a group do not have neurochemical changes that are found in PD, do not respond to medications used to treat PD, are not hyposmic as is found in PD, and neuroimaging studies do not find changes of PD when groups are compared.

CONCLUSION

The overwhelming amount of evidence suggests that any link between ET and PD is coincidental and not biological. Prospective, longitudinal cohort studies with standardized clinical and biomarker assessments followed by neuropathologic confirmation are needed.

Substantia nigra hyperechogenicity is a risk marker of Parkinson's disease: no

During the past two decades, transcranial sonography (TCS) has developed to an increasingly used brain imaging method that visualizes characteristic patterns of basal ganglia alterations in distinct movement disorders. Since the discovery of a characteristic abnormal hyperechogenic appearance of substantia nigra (SN) on TCS in Parkinson's disease (PD), which is stable during the course of the disease and probably present already in preclinical disease stages, the results of several studies have promoted the idea that this TCS finding in healthy subjects might be a risk marker of PD. The present view summarizes current scientific evidence favouring the idea that the TCS finding of SN hyperechogenicity alone may not be a (strong) risk marker of PD. Especially, it is discussed how reliable this TCS finding is, whether this TCS finding can be regarded as a progression marker or a risk marker of PD, how strongly it may indicate a risk of PD, what else if not an increased risk of PD could be indicated, and which role TCS of SN may finally play in the detection of subjects at risk of PD.