Midbrain transcranial sonography in Korean patients with Parkinson's disease

Clinical findings of hyperechoic substantia nigra in patients with Parkinson's disease

This study aims to analyse hyperechoic substantia nigra (HSN) characteristics and the correlation of HSN with clinical features and blood biomarkers in patients with Parkinson's disease (PD). Transcranial sonography (TCS) evaluations of the substantia nigra (SN) were performed in 40 healthy controls and 71 patients with PD, including patients with SN hyperechogenicity (SN+) and those with normal SN echogenicity (SN-). Evaluation of motor and non-motor symptoms was assessed by a series of rating scales. The uricase method was used to determine serum uric acid (UA) levels, and enzyme-linked immunosorbent assay (ELISA) was used to measure plasma interleukin (IL)-1β levels. TCS showed 92.50% specificity and 61.97% sensitivity in differentiating PD patients from controls. The area of SN+ contralateral to the side of initial motor symptoms (SNcontra) was larger than that ipsilateral to the side of initial motor symptoms (SNipsi). The PDSN+ group had lower Argentine Hyposmia Rating Scale (AHRS) scores and UA levels than the PDSN- group. Binary logistic regression analysis revealed that AHRS scores and UA levels could be independent predictors for HSN. The larger SN echogenic area (SNL) sizes positively correlated with plasma IL-1β levels in PD patients with SN+. The present study provides further evidence of the potential of SN echogenicity as an imaging biomarker for PD diagnosis. PD patients with HSN have more severe non-motor symptoms of hyposmia. HSN in PD patients is related to the mechanism of abnormal iron metabolism and microglial activation.

Substantia Nigra Echogenicity Signal Correlated with Clinical Features in Patients with Parkinson's Disease in Xinjiang

Background

Transcranial sonography (TCS) is a noninvasive test that can reveal structural changes in the substantia nigra (SN) in Parkinson's disease (PD). The purpose of this study was to investigate the relationship between SN signatures and clinical features in PD patients in a multiethnic region of China.

Methods

A total of 147 patients with PD were included in the study, and all of whom had underwent a TCS examination. Clinical information was collected from PD patients, and motor and nonmotor symptoms were assessed using assessment scales.

Results

There were differences in the substantia nigra hyperechogenicity (SNH) area between age of onset, visual hallucinations (VH), and UPDRS3.0 II scores (P < 0.05), patients with late onset PD had a greater SNH area than early onset (0.326 ± 0.352 vs. 0.171 ± 0.194), and PD patients presenting with VH had a greater SNH area than those without hallucinations (0.508 ± 0.670 vs. 0.278 ± 0.659), and further multifactorial analysis showed that a high SNH area was an independent risk factor for development of VH. The area under the ROC curve for predicting VH from the SNH area in PD patients was 0.609 (95% CI: 0.444-0.774). There was a positive correlation between the SNH area and UPDRS3.0-II scores, but further multifactorial analysis showed that SNH was not an independent predictor of the UPDRS3.0-II score.

Conclusion

A high SNH area is an independent risk factor for development of VH, there is a positive correlation between the SNH area and UPDRS3.0 II score, and TCS has guiding significance in predicting clinical VH symptoms and activities of daily living in PD patients.

Transcranial sonography in differential diagnosis of Parkinson disease and other movement disorders

Background:

Reports evaluating the efficacy of transcranial sonography (TCS) for the differential diagnosis of Parkinson disease (PD) and other movement disorders in China are scarce. Therefore, this study aimed to assess the application of TCS for the differential diagnosis of PD, multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and essential tremor (ET) in Chinese individuals.

Methods:

From 2017 to 2019, 500 inpatients treated at the Department of Dyskinesia, Beijing Tiantan Hospital, Capital Medical University underwent routine transcranial ultrasound examination. The cross-sections at the midbrain and thalamus levels were scanned, and the incidence rates of substantia nigra (SN) positivity and the incidence rates of lenticular hyperechoic area were recorded. The echo of the SN was manually measured.

Results:

Of the 500 patients, 125 were excluded due to poor signal in temporal window sound transmission. Among the 375 individuals with good temporal window sound transmission, 200 were diagnosed with PD, 90 with ET, 50 with MSA, and 35 with PSP. The incidence rates of SN positivity differed significantly among the four patient groups (χ² = 121.061, P < 0.001). Between-group comparisons were performed, and the PD group showed a higher SN positivity rate than the ET (χ² = 94.898, P < 0.017), MSA (χ² = 57.619, P < 0.017), and PSP (χ² = 37.687, P < 0.017) groups. SN positivity showed a good diagnostic value for differentiating PD from the other three movement diseases, collectively or individually. The incidences of lenticular hyperechoic area significantly differed among the four patient groups (χ² = 38.904, P < 0.001). Next, between-group comparisons were performed. The lenticular hyperechoic area was higher in the PD group than in the ET (χ² = 6.714, P < 0.017) and MSA (χ² = 18.680, P < 0.017) groups but lower than that in the PSP group (χ² = 0.679, P > 0.017).

Conclusion:

SN positivity could effectively differentiate PD from ET, PSP, and MSA in a Chinese population.

Transcranial sonography imaging of brainstem raphe, substantia nigra and cerebral ventricles in patients with geriatric depression

OBJECTIVES

Geriatric depression is a special condition associated with a chronic course, treatment resistance and vascular processes. However, its neurobiology has not been fully elucidated. There is no study in geriatric depression evaluating deep brain structures with transcranial sonography (TCS) which is a low-cost, non-invasive and practical tool. The present study aimed to evaluate the changes in the echogenicity of brainstem raphe (BR), substantia nigra (SN) and ventricular diameters by TCS in association with cognitive dysfunctions in patients with geriatric depression.

METHODS

Echogenicity of BR and SN were assessed and transverse diameters of the third ventricle and frontal horns of the lateral ventricles were measured by TCS in 34 patients with DSM-5 major depression and 31 healthy volunteers aged 60 and older. Cognitive functions were evaluated by using Mini Mental State Examination, Montreal Cognitive Assessment Tool, Clock Drawing Test and Subjective Memory Complaints Questionnaire.

RESULTS

Although depressed patients had more subjective memory complaints than controls, they had similar cognitive performances. Reduced echogenicity (interrupted/invisible echogenic line) of BR was found to be significantly higher and the ventricular diameters were larger in the depressed group. There was no difference between the groups in terms of SN echogenicity. There was no correlation between ventricular diameters and depression severity or cognitive functions.

CONCLUSIONS

Results of the present study are important in terms of pointing out neurobiological changes related to geriatric depression which are in parallel with the results of the studies in younger patients with depression. However, long-term follow-up studies are required for accurate differentiation of neurocognitive disorders.

Transcranial brain sonography for Parkinsonian syndromes

Substantia nigra (SN) hyperechogenicity has been proved to be a characteristic finding for idiopathic Parkinson's disease (PD), occurring in more than 90% of the patients. This echofeature is owed to increased amounts of iron in the SN region and reflects a functional impairment of the nigrostriatal dopaminergic system. In a prospective blinded study in which a group of patients with early mild signs and symptoms of unclear Parkinsonism were followed until a definite clinical diagnosis of PD, the hyperechogenicity of the SN was demonstrated to be highly predictive of a final diagnosis of PD. For the diagnosis of PD in individuals with early motor symptoms, both the sensitivity and positive predictive value of SN hyperechogenicity were higher than 90% and both the specificity and negative predictive value were higher than 80%. For early differential diagnosis between PD and atypical Parkinsonian syndromes, the sensitivity and positive predictive value of SN hyperechogenicity were higher than 90%, and both the specificity and negative predictive value were higher than 80%. The diagnostic specificity is increased if combining the TCS findings of SN, lenticular nucleus and third ventricle. In asymptomatic adult subjects, SN hyperechogenicity, at least unilaterally, indicates a subclinical functional insufficiency of the nigrostriatal dopaminergic system. Recent papers revealed that SN hyperechogenicity might suggest preclinical PD. Reduced echogenicity of midbrain raphe indicates increased risk of depression in PD patients. Caudate nucleus hyperechogenicity has been associated with drug-induced psychosis, and frontal horn dilatation >20 mm with dementia. Transcranial brain sonography can be a valuable tool for managing patients with Parkinsonian signs and symptoms.

Increased substantia nigra echogenicity correlated with visual hallucinations in Parkinson's disease: a Chinese population-based study

As a noninvasive technique, transcranial sonography (TCS) of substantia nigra (SN) has gradually showed its effectiveness not only in diagnosis but also in understanding clinical features of Parkinson’s Disease (PD). This study aimed to further evaluate TCS for clinical diagnosis of PD, and to explore the association between sonographic manifestations and visual hallucinations (VH). A total of 226 subjects including 141 PD patients and 85 controls were recruited. All participants received TCS. A series of rating scales to evaluate motor and non-motor symptoms were performed in PD patients. Results showed that 172 subjects were successfully assessed by TCS. The area of SN was greater in PD patients than that in controls (P < 0.001). As receiver-operating characteristic (ROC) curve analysis showed, the best cutoff value for the larger SN echogenicity size was 23.5 mm² (sensitivity 70.3%, specificity 77.0%). Patients with VH had larger SN area (P = 0.019), as well as higher Non-Motor Symptoms Scale (NMSS) scores (P = 0.018). Moreover, binary logistic regression analysis indicated that SN hyperechogenicity (odds ratio = 4.227, P = 0.012) and NMSS scores (odds ratio = 0.027, P = 0.042) could be the independent predictors for VH. In conclusion, TCS can be used as an auxiliary diagnostic tool for Parkinson’s disease. Increased SN echogenicity is correlated with VH in Parkinson’s disease, possibly because the brain stem is involved in the mechanism in the onset of VH. Further studies are needed to confirm these findings.

Substantia Nigra Echogenicity Associated with Clinical Subtypes of Parkinson's Disease

BACKGROUND

It is debatable whether transcranial sonography (TCS) could be a biomarker for monitoring disease progression. Various phenotypes of Parkinson's disease (PD) may be a major reason contributing to the inconsistency.

OBJECTIVE

We classified PD patients into different subtypes and evaluated the correlation between SN echogenicity and disease progression.

METHODS

A total of 411 PD patients were included in this study. TCS evaluations of the substantia nigra (SN) were performed, and motor and non-motor symptoms were assessed by a series of rating scales in all PD patients.

RESULTS

Three hundred and thirteen patients had appropriate temporal acoustic bone windows, and they were divided into three subgroups according to disease onset age. SN hyperechogenicity (SN+) was found to be associated with age, gender, disease duration, H-Y stage and UPDRS-II scores in 220 middle-age onset patients. Regression analysis identified both disease duration and gender as independent predictors for SN+. When this distinct group was separated into male and female subgroups, the correlation between larger SN echogenicity (SNL) and disease duration was positive in males rather than females. When these middle-age onset male patients were classified as tremor dominant (TD) and non-TD subtypes, it turned out that correlation between disease duration and SNL only existed in male non-TD PD patients.

CONCLUSIONS

Our study demonstrated correlation between the size of SN echogenicity and disease duration in Chinese patients with PD who were male non-TD subtypes with middle-age onset, suggesting the formation of SN echogenicity might be a dynamic process following disease progression in this distinct subtype.

Accuracy of Transcranial Sonography of the Substantia Nigra for Detection of Parkinson's Disease: A Systematic Review and Meta-analysis

A systematic review and meta-analysis were conducted to evaluate the diagnostic accuracy of substantia nigra hyper-echogenicity by transcranial sonography (TCS) for the diagnosis of Parkinson's disease (PD). PubMed, Embase and the Cochrane Library were electronically searched from inception to June 2018 for all relevant studies. The methodological quality of each study was evaluated by two independent reviewers, who used the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Articles reporting information sufficient to calculate the sensitivity and specificity of TCS to diagnose PD were included. Statistical analysis included data pooling, heterogeneity testing, sensitivity analyses and forest meta-regression. Thirty-nine studies (3123 participants with PD) were analyzed. The pooled sensitivity and specificity of TCS were 0.84 (95% confidence interval: 0.81-0.87) and 0.85 (0.80-0.88), respectively, for differentiating PD from normal controls or participants with other parkinsonian syndromes. In the secondary outcome, PD participants exhibited a significant increase in substantia nigra areas than either normal controls (0.14 [0.12-0.16], p < 0.0001) or participants with other parkinsonian syndromes (0.11 [0.08-0.13], p < 0.0001). This meta-analysis revealed the high diagnostic performance of TCS in differentiating patients with PD from both normal controls and participants with other parkinsonian syndromes.

Advances in the Research of Risk Factors and Prodromal Biomarkers of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world. With the advent of an aging population and improving life expectancy worldwide, the number of PD patients is expected to increase, which may lead to an urgent need for effective preventive and diagnostic strategies for PD. Although there is increasing research regarding the pathogenesis of PD, there is limited knowledge regarding the prevention of PD. Moreover, the diagnosis of PD depends on clinical criteria, which require the occurrence of bradykinesia and at least one symptom of rest tremor or rigidity. However, converging evidence from clinical, genetic, neuropathological, and imaging studies suggests the initiation of PD-specific pathology prior to the initial presentation of these classical motor clinical features by years or decades. This latent stage of neurodegeneration in PD is a particularly important stage for effective neuroprotective therapies, which might retard the progression or prevent the onset of PD. Therefore, the exploration of risk factors and premotor biomarkers is not only crucial to the early diagnosis of PD but is also helpful in the development of effective neuroprotection and health care strategies for appropriate populations at risk for PD. In this review, we searched and summarized ∼249 researches and 31 reviews focusing on the risk factors and prodromal biomarkers of PD and published in MEDLINE.

Comprehensive Analysis of the Association Between the rs1138272 Polymorphism of the GSTP1 Gene and Cancer Susceptibility

Background: We obtained conflicting results regarding the relationship between the genetic role of the rs1138272 C/T polymorphism of the GSTP1 (Glutathione S-Transferase pi) gene and the risk of various cancers.

Methods: Using the presently available data, a meta-analysis was conducted to comprehensively evaluate the genetic relationship between the GSTP1 rs1138272 polymorphism and cancer susceptibility.

Results: A total of 43 studies including 15,688 cases and 17,143 controls were recruited into our quantitative synthesis. In the overall population, we observed an increased risk of overall cancer cases, compared with unrelated controls, in the genetic models of allele T vs. allele C (P-association = 0.007, OR = 1.17), carrier T vs. carrier C (P-association = 0.035, OR = 1.11), TT vs. CC (P-association = 0.002, OR = 1.45), TT vs. CC+CT (P-association = 0.009, OR = 1.42), and CT+TT vs. CC (P-association = 0.027, OR = 1.13). We detected similar positive results within the Asian population. Additionally, there was a significant increase in the incidence of cancer for Africans under all genetic models (all P-association < 0.05, OR > 1). When targeting the Caucasian population, we detected a positive association with the TT vs. CC and TT vs. CC+CT models in the “Colorectal cancer” (P-association < 0.05, OR < 1) and “Head and neck cancer” (P-association < 0.05, OR > 1) subgroups. For the “Lung cancer” subgroup, we observed a slightly increased risk in Caucasians under the models of allele T vs. allele C, carrier T vs. carrier C, CT vs. CC, and CT+TT vs. CC (P-association < 0.05, OR > 1).

Conclusion: The TT genotype of the GSTP1 rs1138272 polymorphism is likely related to the susceptibility to overall cancer in the Asian and African populations and, specifically, “Colorectal” and “Head and neck” cancers in the Caucasian population. In addition, the CT genotype of the GSTP1 rs1138272 polymorphism may be linked to the risk of lung cancer in Caucasians. Additional evidence is required to confirm this conclusion.

Transcranial sonography in psychiatry as a potential tool in diagnosis and research

OBJECTIVES

During the last two decades transcranial sonography (TCS) of the brain parenchyma evolved from a pure research tool to a clinical relevant neuroimaging method especially in Parkinson's disease and related movement disorders. The aim of this systematic review is to update and summarise the published TCS findings in psychiatric disorders and critically address the question whether TCS may be a valuable tool for the diagnosis or differential diagnosis of psychiatric disorders similarly to the field of movement disorders.

METHODS

This paper provides detailed information about the perspectives and limitations of TCS, including guidelines for the scanning procedures, assessment of midbrain structures and discusses the potential causes of the ultrasound abnormalities in psychiatric disorders.

RESULTS

Changes in the echogenicity of subcortical brain structures were detected in different disorders, such as obsessive-compulsive disorder, autism spectrum disorder, schizophrenia, panic disorder, attention-deficit/hyperactivity (ADHD), bipolar disorder and depressive disorder. Although the physical properties of brain tissue underlying the echogenic features in TCS are largely unknown, no alternative technique provides the same insight into the specific central nervous structural characteristics.

CONCLUSIONS

Urgent research questions to further clarify the underlying pathophysiological and structural alterations are further outlined to bring this promising technique to the clinic.

The role of substantia nigra sonography in the differentiation of Parkinson's disease and multiple system atrophy

Background

The differential diagnosis of Parkinson's disease (PD) and multiple system atrophy (MSA) remains a challenge, especially in the early stage. Here, we assessed the value of transcranial sonography (TCS) to discriminate non-tremor dominant (non-TD) PD from MSA with predominant parkinsonism (MSA-P).

Methods

Eighty-six MSA-P patients and 147 age and gender-matched non-TD PD patients who had appropriate temporal acoustic bone windows were included in this study. All the patients were followed up for at least 2 years to confirm the initial diagnosis. Patients with at least one substantia nigra (SN) echogenic size ≥18 mm² were classified as hyperechogenic, those with at least one SN echogenic size ≥25 mm² was defined as markedly hyperechogenic.

Results

The frequency of SN hyperechogenicity in non-TD PD patients was significantly higher than that in MSA-P patients (74.1% vs. 38.4%, p <  0.001). SN hyperechogenicity discriminated non-TD PD from MSA-P with sensitivity of 74.1%, specificity of 61.6%, and positive predictive value of 76.8%. If marked SN hyperechogenicity was used as the cutoff value (≥ 25 mm²), the sensitivity decreased to 46.3%, but the specificity and positive predictive value increased to 80.2 and 80.0%. Additionally, in those patients with SN hyperechogenicity, positive correlation between SN hyperechogenicity area and disease duration was found in non-TD PD rather than in MSA-P patients. In this context, among early-stage patients with disease duration ≤3 years, the sensitivity, specificity and positive predictive value of SN hyperechogenicity further declined to 69.8%, 52.2%, and 66.7%, respectively.

Conclusions

TCS could help discriminate non-TD PD from MSA-P in a certain extent, but the limitation was also obvious with relatively low specificity, especially in the early stage.

Transcranial sonography in idiopathic REM sleep behavior disorder and multiple system atrophy

AIM

We investigated preclinical abnormalities as revealed by transcranial sonography (TCS) in patients with idiopathic rapid eye movement sleep behavior disorder (iRBD) compared with those revealed in patients with multiple system atrophy (MSA) or Parkinson's disease (PD) and in normal controls.

METHODS

Twenty-two patients with iRBD, 21 patients with MSA, 22 patients with PD, and 21 normal controls were included in this study. All participants underwent one night of video-polysomnography monitoring, and the sleep parameters were analyzed using Polysmith software and by visual analysis. TCS was performed following a standardized procedure. The echogenicity of the substantia nigra and basal ganglia were evaluated.

RESULTS

A greater proportion of PD patients were found to have substantia nigra hyperechogenicity (86.4%) when compared to iRBD patients (31.8%), MSA patients (23.8%), and normal controls (4.8%) (P < 0.001). Fourteen MSA patients (66.7%) and 11 iRBD patients (50.0%) had hyperechogenicity in the basal ganglia, whereas hyperechogenicity in the basal ganglia was less frequent in PD patients (18.2%) and normal controls (9.5%) (P < 0.001). Poor sleep efficiency, less stage II sleep time, and more periodic leg movements were found in MSA and PD patients, whereas iRBD patients had almost normal sleep.

CONCLUSION

Some iRBD patients had basal ganglia hyperechogenicity that was similar to that observed in MSA, which may represent another possible convert direction. The present study further confirmed iRBD as a prodromal stage of synucleinopathy. TCS could detect subclinical changes and thus might provide useful markers for identifying individuals at increased risk for developing a synucleinopathy.

Use of Gray-Level Histograms to Assess Substantia Nigra Echogenicity in Transcranial Sonography Images of Parkinson Disease Patients

A substantial body of research has shown that Parkinson disease (PD) patients display an enlarged hyperechogenic substantia nigra (SN) by transcranial sonography (TCS). Nonetheless, the categorization of SN echogenicity is still subjective. A method is described to quantify SN echogenicity based on the gray-level histograms of digitized TCS images. In 31 PD patients and 57 controls, the gray-scale mean (GSM) of the SN, mesencephalon, and basal cisterns and their ratios were assessed using image-editing computer software. The GSM values were compared between the groups and correlated with age, SN area, and disease duration. The SN GSM was significantly higher in the PD group ( P < .05) with a positive correlation with age but not with disease duration. In this cohort of participants, mesencephalon echogenicity was found to increase with disease duration. These results would suggest quantitatively SN hyperechogenicity in PD. Quantifying SN echogenicity is feasible and might minimize subjectivity in PD diagnosis by TCS. The method has the potential to disclose subtle changes in other midbrain structures’ echogenicity engendered by the disease process as well.

Transcranial sonography findings related to depression in parkinsonian disorders: cross-sectional study in 126 patients

Background. Transcranial sonography (TCS) has emerged as a potential diagnostic tool for Parkinson’s disease. Recent research has suggested that abnormal echogenicity of substantia nigra, raphe nuclei and third ventricle is associated with increased risk of depression among these patients. We sought to reproduce these findings in an ongoing larger study of patients with parkinsonian syndromes.

Methods. A total of 126 patients with parkinsonian symptoms underwent the Hamilton Depression Scale, and TCS of the substantia nigra (SN) (n = 126), the raphe nuclei (RN) (n = 80) and the third ventricle (n = 57). We then calculated the correlation between depression and hyper-echogenic SN, hypo-echogenic RN and a wider third ventricle.

Results. In patients with PD we found no significant difference of the SN between non-depressed and depressed patients (46% vs. 22%; p = 0.18). Non-depressed patients with other parkinsonisms more often had hyperechogenicity of the SN than depressed patients (51% vs. 0%; p = 0.01). We found no relation between depression and the echogenicity of the RN or the width of the third ventricle.

Conclusions. In patients with parkinsonian syndromes, we found no association between depression and hyper-echogenic SN, hypo-echogenic RN or a wider third ventricle, as determined by transcranial sonography.

Developments in the role of transcranial sonography for the differential diagnosis of parkinsonism

In the last two decades transcranial sonography (TCS) has developed as a valuable, supplementary tool in the diagnosis and differential diagnosis of movement disorders. In this review, we highlight recent evidence supporting TCS as a reliable method in the differential diagnosis of parkinsonism, combining substantia nigra (SN), basal ganglia and ventricular system findings. Moreover, several studies support SN hyperechogenicity as one of most important risk factors for Parkinson's disease (PD). The advantages of TCS include short investigation time, low cost and lack of radiation. Principal limitations are still the dependency on the bone window and operator experience. New automated algorithms may reduce the role of investigator skill in the assessment and interpretation, increasing TCS diagnostic reliability. Based on the convincing evidence available, the EFNS accredited the method of TCS a level A recommendation for supporting the diagnosis of PD and its differential diagnosis from secondary and atypical parkinsonism. An increasing number of training programmes is extending the use of this technique in clinical practice.

Adults with a history of illicit amphetamine use exhibit abnormal substantia nigra morphology and parkinsonism

INTRODUCTION

The sonographic appearance of the substantia nigra is abnormally bright and enlarged (hyperechogenic) in young adults with a history of illicit stimulant use. The abnormality is a risk factor for Parkinson's disease. The aim of the current study was to identify the type of illicit stimulant drug associated with substantia nigra hyperechogenicity and to determine if individuals with a history of illicit stimulant use exhibit clinical signs of parkinsonism. We hypothesised that use of amphetamines (primarily methamphetamine) is associated with substantia nigra hyperechogenicity and clinical signs of parkinsonism.

METHODS

The area of echogenic signal in the substantia nigra was measured in abstinent human amphetamine users (n = 27; 33 ± 8 years) and in three control groups comprising a) 'ecstasy' users (n = 19; 23 ± 3 years), b) cannabis users (n = 30; 26 ± 8 years), and c) non-drug users (n = 37; 25 ± 7 years). A subset of subjects (n = 55) also underwent a neurological examination comprising the third and fifth part of the Unified Parkinson's Disease Rating Scale.

RESULTS

Area of substantia nigra echogenicity was significantly larger in the amphetamine group (0.276 ± 0.080 cm(2)) than in the control groups (0.200 ± 0.075, 0.190 ± 0.049, 0.191 ± 0.055 cm(2), respectively; P < 0.002). The score on the clinical rating scale was also significantly higher in the amphetamine group (8.4 ± 8.1) than in pooled controls (3.3 ± 2.8; P = 0.002).

CONCLUSION

Illicit use of amphetamines is associated with abnormal substantia nigra morphology and subtle clinical signs of parkinsonism. The results support epidemiological findings linking use of amphetamines, particularly methamphetamine, with increased risk of developing Parkinson's disease later in life.

Diagnostic Accuracy of Transcranial Sonography of the Substantia Nigra in Parkinson's disease: A Systematic Review and Meta-analysis

A large number of articles have reported substantia nigra hyperechogenicity in Parkinson’s disease (PD) and have assessed the diagnostic accuracy of transcranial sonography (TCS); however, the conclusions are discrepant. Consequently, this systematic review and meta-analysis aims to consolidate the available observational studies and provide a comprehensive evaluation of the clinical utility of TCS in PD. Totally, 31 studies containing 4,386 participants from 13 countries were included. A random effects model was utilized to pool the effect sizes. Meta-regression and sensitivity analysis were performed to explore potential heterogeneity. Overall diagnostic accuracy of TCS in differentiating PD from normal controls was quite high, with a pooled sensitivity of 0.83 (95% CI: 0.81–0.85) and a pooled specificity of 0.87 (95% CI: 0.85–0.88). The positive likelihood ratio, the negative likelihood ratio and diagnostic odds ratio were calculated 6.94 (95% CI: 5.09–9.48), 0.19 (95% CI: 0.16–0.23), and 42.89 (95% CI: 30.03–61.25) respectively. Our systematic review of the literature and meta-analysis suggest that TCS has high diagnostic accuracy in the diagnosis of PD when compared to healthy control.

Substantia nigra echogenicity correlated with clinical features of Parkinson's disease

BACKGROUND

Transcranial sonography can display structural alterations in the substantia nigra (SN) of patients with Parkinson's disease (PD), and is considered to be a potential useful tool for the diagnosis of PD. The aim of this study was to assess the correlation between SN echogenicity and clinical features in Chinese patients with PD.

METHODS

A total of 420 subjects including 290 patients with PD and 130 controls were recruited from the neurological clinic or the community. Transcranial sonographic evaluations of the SN were performed in all subjects, and motor and non-motor symptoms were thoroughly assessed by a series of rating scales in PD patients.

RESULTS

Two hundred and one patients were successfully assessed by transcranial sonography. SN hyperechogenicity was found to be associated with male sex (p = 0.004), higher scores on the Unified Parkinson's Disease Rating Scale (UPDRS) part II (p = 0.001) and autonomic symptoms scores (p = 0.003). Moreover, regression analysis revealed that UPDRS part II scores (odds ratio = 1.141, p < 0.001) and gender (odds ratio = 2.409, p = 0.007) could be the independent predictors for SN hyperechogenicity; in addition, among all items of UPDRS part II, speech, dressing, hygiene, and turning in bed and adjusting bed clothes significantly correlated with SN hyperechogenicity.

CONCLUSIONS

This is the first report suggesting the correlation between SN echogenicity and UPDRS part II, and we conclude that increased SN echogenicity might reflect more severe disease disability or poorer medical response.

Substantia Nigra Hyperechogenicity: Validation of Transcranial Sonography for Parkinson Disease Diagnosis in a Large Estonian Cohort

OBJECTIVES

Substantia nigra hyperechogenicity is a promising biomarker for Parkinson disease (PD). Substantia nigra hyperechogenicity has previously been established as a useful diagnostic criterion in several European and Asian patient cohorts. However, diagnostic cutoff values for substantia nigra hyperechogenicity remain unknown for most patient populations. This study validated the diagnostic accuracy of substantia nigra hyperechogenicity in a large cohort of patients with PD in Estonia.

METHODS

The study included 300 patients with PD from Estonia, representing 10% of the national PD patient population, and 200 healthy control participants. To define the optimal cutoff value in the PD cohort, data from a single assessment versus repetitive assessments by transcranial sonography were compared. With the use of 3 repetitive assessments, the diagnostic accuracy of the data was measured. In addition, calculations for percentile values were used to define substantia nigra hyperechogenicity among controls.

RESULTS

Our data showed that the multiassessment approach yielded higher diagnostic accuracy than a single assessment (P = .021). The highest diagnostic accuracy was achieved by using the measurement mean to define substantia nigra hyperechogenicity, which was 0.23 cm(2) (sensitivity, 88.7%; specificity, 92.2%), whereas single measurements detected PD with higher sensitivity (sensitivity, 93.2%; specificity, 85.1%). No significant difference was found between mean and median measurements (P= .18).

CONCLUSIONS

This study indicates the diagnostic merit of transcranial sonography in PD diagnosis in an additional population and demonstrates that transcranial sonography of the substantia nigra is a relevant and useful diagnostic tool for patients with PD.

Transcranial sonography of the substantia nigra and its correlation with DAT-SPECT in the diagnosis of Parkinson's disease

INTRODUCTIONS

Transcranial sonography (TCS) of the substantia nigra is a new and promising method to diagnose Parkinson's disease (PD) but its effectiveness is controversial.

METHODS

All 55 PD patients involved in the study underwent single photon emission computed tomography (SPECT) imaging using the labeled dopamine transporter radiotracer (99m)Tc-TRODAT-1 to assess nigrostriatal dopaminergic function. The echogenicity of the substantia nigra was measured by TCS in all patients who received DAT-SPECT scanning. Finally, statistical analysis was carried out to determine the diagnostic accuracy of TCS as well as its correlation with (99m)Tc-TRODAT-1 SPECT, its positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

Contralateral striatal (99m)Tc-TRODAT-1 uptake was significantly reduced compared to ipsilateral striatal uptake, and had a negative correlation with UPDRS-Ⅲ(r = -0.334, p = 0.013), disease duration (r = -0.393, p = 0.003) and H-Y stage (r = -0.330, p = 0.014). After TCS measurement, the contralateral SN echogenic area was similar to the ipsilateral SN echogenic area (27.77 ± 13.19 vs 25.98 ± 11.94 mm(2), p = 0.402, n = 24). No correlation was identified between TCS and UPDRS-Ⅲ (r = 0.383, p = 0.065), disease duration (r = 0.371, p = 0.075) or H-Y stage (r = 0.259, p = 0.222). The sensitivity and specificity of SN TCS for the diagnosis of PD were calculated as 64.70% and 60% according to DAT-SPECT, respectively, while the positive predictive value and negative predictive value was calculated as 91.67% and 20%, respectively.

CONCLUSIONS

Compared to DAT-SPECT, TCS is a non-radioactive and convenient procedure to perform. In our investigation, TCS had no correlation with DAT-SPECT. However, the high positive predictive value of TCS highlights its possible utility as a routine diagnostic test.

Sonography for diagnosis of Parkinson disease-from theory to practice: a study on 300 participants

OBJECTIVES

Hyperechogenicity of the substantia nigra on transcranial sonography is used for diagnosing Parkinson disease (PD). Cutoff values for the substantia nigra echogenic area, defining substantia nigra hyperechogenicity, vary among ultrasound systems from different manufacturers. In this study we wanted to determine the cutoff criterion for a Toshiba (Tokyo, Japan) system and to assess its diagnostic value.

METHODS

Three hundred participants (controls, n = 138; patients with PD, n = 105; and patients with essential tremor, n = 57) underwent transcranial sonography following a standardized protocol.

RESULTS

The substantia nigra was assessable in 92.7% of all participants. The substantia nigra echogenic area (larger of bilateral measurements) was larger in patients with PD (mean ± SD, 0.24 ± 0.05 cm(2)) than controls (0.14 ± 0.05 cm(2); P < .001) and patients with essential tremor (0.14 ± 0.04 cm(2); P < .001). Substantia nigra echogenicity was larger in male participants (0.20 ± 0.07 cm(2)) than female participants (0.15 ± 0.06 cm(2); P< .001). Age did not correlate with substantia nigra echogenicity in any group. Frontal horn width was larger and lenticular nucleus hyperechogenicity and a discontinuous raphe were more frequent in the PD group than the other groups. On multivariate analysis, only substantia nigra hyperechogenicity was associated with the diagnosis of PD. The 90th-percentile substantia nigra echogenic area in the control group, which defined marked substantia nigra hyperechogenicity, also represented the optimum cutoff value for discrimination of PD from non-PD participants on receiver operating characteristic curve analysis (area under the curve, 0.913; Youden index, 0.73). This cutoff value (≥0.21 cm(2), larger of bilateral measurements) yielded sensitivity of 83% and specificity of 90% for the diagnosis of PD.

CONCLUSIONS

Transcranial sonography shows good diagnostic validity for diagnosis of PD when implemented according to a strictly standardized protocol.

How to measure substantia nigra hyperechogenicity in Parkinson disease: detailed guide with video

The detection of an enlarged echogenic size ("hyperechogenicity") of the substantia nigra on transcranial sonography is increasingly used for the early and differential diagnosis of Parkinson disease. However, the diagnostic value of substantia nigra sonography depends on the quality of its execution. This article with an accompanying video presents a step-by-step description and demonstration of ultrasound system settings, typical errors in assessment of the substantia nigra, planimetric measurement of substantia nigra echogenicity according to current guidelines, and its diagnostic implications in 2 exemplary patients with parkinsonism. Published cutoff values for grading substantia nigra hyperechogenicity with different ultrasound systems and novel technologies are reviewed.

EFNS/MDS-ES/ENS [corrected] recommendations for the diagnosis of Parkinson's disease

BACKGROUND

A Task Force was convened by the EFNS/MDS-ES Scientist Panel on Parkinson's disease (PD) and other movement disorders to systemically review relevant publications on the diagnosis of PD.

METHODS

Following the EFNS instruction for the preparation of neurological diagnostic guidelines, recommendation levels have been generated for diagnostic criteria and investigations.

RESULTS

For the clinical diagnosis, we recommend the use of the Queen Square Brain Bank criteria (Level B). Genetic testing for specific mutations is recommended on an individual basis (Level B), taking into account specific features (i.e. family history and age of onset). We recommend olfactory testing to differentiate PD from other parkinsonian disorders including recessive forms (Level A). Screening for pre-motor PD with olfactory testing requires additional tests due to limited specificity. Drug challenge tests are not recommended for the diagnosis in de novo parkinsonian patients. There is an insufficient evidence to support their role in the differential diagnosis between PD and other parkinsonian syndromes. We recommend an assessment of cognition and a screening for REM sleep behaviour disorder, psychotic manifestations and severe depression in the initial evaluation of suspected PD cases (Level A). Transcranial sonography is recommended for the differentiation of PD from atypical and secondary parkinsonian disorders (Level A), for the early diagnosis of PD and in the detection of subjects at risk for PD (Level A), although the technique is so far not universally used and requires some expertise. Because specificity of TCS for the development of PD is limited, TCS should be used in conjunction with other screening tests. Conventional magnetic resonance imaging and diffusion-weighted imaging at 1.5 T are recommended as neuroimaging tools that can support a diagnosis of multiple system atrophy (MSA) or progressive supranuclear palsy versus PD on the basis of regional atrophy and signal change as well as diffusivity patterns (Level A). DaTscan SPECT is registered in Europe and the United States for the differential diagnosis between degenerative parkinsonisms and essential tremor (Level A). More specifically, DaTscan is indicated in the presence of significant diagnostic uncertainty such as parkinsonism associated with neuroleptic exposure and atypical tremor manifestations such as isolated unilateral postural tremor. Studies of [(123) I]MIBG/SPECT cardiac uptake may be used to identify patients with PD versus controls and MSA patients (Level A). All other SPECT imaging studies do not fulfil registration standards and cannot be recommended for routine clinical use. At the moment, no conclusion can be drawn as to diagnostic efficacy of autonomic function tests, neurophysiological tests and positron emission tomography imaging in PD.

CONCLUSIONS

The diagnosis of PD is still largely based on the correct identification of its clinical features. Selected investigations (genetic, olfactory, and neuroimaging studies) have an ancillary role in confirming the diagnosis, and some of them could be possibly used in the near future to identify subjects in a pre-symptomatic phase of the disease.

The glutathione S-transferase P1 341C>T polymorphism and cancer risk: a meta-analysis of 28 case-control studies

Background

GSTP1, which is one major group of the glutathione S-transferase family, plays an important role in the metabolism of carcinogens and toxins, reducing damage of DNA as a suppressor of carcinogenesis. The 341C>T polymorphism of the GSTP1 has been implicated in cancer risk through cutting down its metabolic detoxification activities. However, results from previous studies remain conflicting rather than conclusive. To clarify the correlation and provide more statistical evidence for detecting the significance of 341C>T, a meta-analysis was conducted.

Methodology/Principal Findings

The relevant studies were identified through searching of PubMed, Embase, ISI Web of Knowledge and China National Knowledge Infrastructure in August 2012, and selected based on the established inclusion criteria for publications, then a meta-analysis was performed to quantitatively summarize the association of GSTP1 341C>T polymorphism with cancer susceptibility. Stratified analyses were employed to identify the source of heterogeneity. Publication bias was evaluated as well as sensitivity analysis. Based on 28 case-control studies with 13249 cases and 16798 controls, the pooled results indicated that the variant genotypes significantly increased the risk of cancer in homozygote comparison (TT versus CC: P = 0.012, OR = 1.40, 95% CI: 1.08–1.81, P_het. = 0.575), and recessive model (TT versus CT/CC: P = 0.012, OR = 1.40, 95% CI: 1.08–1.81, P_het. = 0.562). This was confirmed when stratified analyses were conducted according to ethnicity, source of control, matched control, quality score and cancer types. Moreover, significantly increased risk of cancer was also found in lung cancer (heterozygote comparison and dominant model). The stability of these observations was confirmed by a sensitivity analysis. Begger's funnel plot and Egger's test did not reveal any publication bias.

Conclusions/Significance

This meta-analysis suggests that the GSTP1 341C>T polymorphism may contribute to genetic susceptibility to cancer, especially to lung cancer, and in Asian population. Nevertheless, additional well-designed studies focusing on different ethnicity and cancer types are needed to provide a more exact and comprehensive conclusion.

Illicit stimulant use is associated with abnormal substantia nigra morphology in humans

Use of illicit stimulants such as methamphetamine, cocaine, and ecstasy is an increasing health problem. Chronic use can cause neurotoxicity in animals and humans but the long-term consequences are not well understood. The aim of the current study was to investigate the long-term effect of stimulant use on the morphology of the human substantia nigra. We hypothesised that history of illicit stimulant use is associated with an abnormally bright and enlarged substantia nigra (termed 'hyperechogenicity') when viewed with transcranial sonography. Substantia nigra morphology was assessed in abstinent stimulant users (n = 36; 31±9 yrs) and in two groups of control subjects: non-drug users (n = 29; 24±5 yrs) and cannabis users (n = 12; 25±7 yrs). Substantia nigra morphology was viewed with transcranial sonography and the area of echogenicity at the anatomical site of the substantia nigra was measured at its greatest extent. The area of substantia nigra echogenicity was significantly larger in the stimulant group (0.273±0.078 cm(2)) than in the control (0.201±0.054 cm(2); P<0.001) and cannabis (0.202±0.045 cm(2); P<0.007) groups. 53% of stimulant users exhibited echogenicity that exceeded the 90(th) percentile for the control group. The results of the current study suggest that individuals with a history of illicit stimulant use exhibit abnormal substantia nigra morphology. Substantia nigra hyperechogenicity is a strong risk factor for developing Parkinson's disease later in life and further research is required to determine if the observed abnormality in stimulant users is associated with a functional deficit of the nigro-striatal system.

Specificity and sensitivity of transcranial sonography of the substantia nigra in the diagnosis of Parkinson's disease: prospective cohort study in 196 patients

OBJECTIVE

Numerous ultrasound studies have suggested that a typical enlarged area of echogenicity in the substantia nigra (SN+) can help diagnose idiopathic Parkinson's disease (IPD). Almost all these studies were retrospective and involved patients with well-established diagnoses and long-disease duration. In this study the diagnostic accuracy of transcranial sonography (TCS) of the substantia nigra in the patient with an undiagnosed parkinsonian syndrome of recent onset has been evaluated.

DESIGN

Prospective cohort study for diagnostic accuracy.

SETTING

Neurology outpatient clinics of two teaching hospitals in the Netherlands.

PATIENTS

196 consecutive patients, who were referred to two neurology outpatient clinics for analysis of clinically unclear parkinsonism. Within 2 weeks of inclusion all patients also underwent a TCS and a (123)I-ioflupane Single Photon Emission CT (FP-CIT SPECT) scan of the brain (n=176).

OUTCOME MEASURES

After 2 years, patients were re-examined by two movement disorder specialist neurologists for a final clinical diagnosis, that served as a surrogate gold standard for our study.

RESULTS

Temporal acoustic windows were insufficient in 45 of 241 patients (18.67%). The final clinical diagnosis was IPD in 102 (52.0%) patients. Twenty-four (12.3%) patients were diagnosed with atypical parkinsonisms (APS) of which 8 (4.0%) multisystem atrophy (MSA), 6 (3.1%) progressive supranuclear palsy (PSP), 6 (3.1%) Lewy body dementia and 4 (2%) corticobasal degeneration. Twenty-one (10.7%) patients had a diagnosis of vascular parkinsonism, 20 (10.2%) essential tremor, 7 (3.6%) drug-induced parkinsonism and 22 (11.2%) patients had no parkinsonism but an alternative diagnosis. The sensitivity of a SN+ for the diagnosis IPD was 0.40 (CI 0.30 to 0.50) and the specificity 0.61 (CI 0.52 to 0.70). Hereby the positive predictive value (PPV) was 0.53 and the negative predictive value (NPV) 0.48. The sensitivity and specificity of FP-CIT SPECT scans for diagnosing IPD was 0.88 (CI 0.1 to 0.95) and 0.68 (CI 0.58 to 0.76) with a PPV of 0.75 and an NPV of 0.84.

CONCLUSIONS

The diagnostic accuracy of TCS in early stage Parkinson's disease is not sufficient for routine clinical use. CLINICALTRIALS.GOV IDENTIFIER: NCT0036819.

Specificity of transcranial sonography in parkinson spectrum disorders in comparison to degenerative cognitive syndromes

Background

Hyperechogenicity of the substantia nigra (SN+), detected by transcranial sonography (TCS), was reported as a characteristic finding in Parkinson's disease (PD), with high diagnostic accuracy values, when compared mainly to healthy controls or essential tremor (ET) group. However, some data is accumulating that the SN + could be detected in other neurodegenerative and even in non-neurodegenerative disorders too. Our aim was to estimate the diagnostic accuracy of TCS, mainly focusing on the specificity point, when applied to a range of the parkinsonian disorders, and comparing to the degenerative cognitive syndromes.

Methods

A prospective study was carried out at the Hospital of Lithuanian University of Health Sciences from January until September 2011. Initially, a TCS and clinical examination were performed on 258 patients and 76 controls. The General Electric Voluson 730 Expert ultrasound system was used. There were 12.8% of cases excluded with insufficient temporal bones, and 4.3% excluded with an unclear diagnosis. The studied sample consisted of the groups: PD (n = 71, 33.2%), ET (n = 58, 27.1%), PD and ET (n = 10, 4.7%), atypical parkinsonian syndromes (APS) (n = 3, 1.4%), hereditary neurodegenerative parkinsonism (HDP) (n = 3, 1.4%), secondary parkinsonism (SP) (n = 23, 10.8%), mild cognitive impairment (MCI) (n = 33, 15.4%), dementia (n = 13, 6.1%), and control (n = 71).

Results

There were 80.3% of PD patients at stages 1 & 2 according to Hoehn and Yahr. At the cut-off value of 0.20 cm² of the SN+, the sensitivity for PD was 94.3% and the specificity - 63.3% (ROC analysis, AUC 0.891), in comparison to the rest of the cohort. At the cut-off value of 0.26 cm², the sensitivity was 90% and the specificity 82.4%.

The estimations for the lowest specificity for PD, in comparison to the latter subgroups (at the cut-off values of 0.20 cm² and 0.26 cm², respectively) were: 0% and 33.3% to APS, 33.3% and 66.7% to HDP, 34.8% and 69.6% to SP, 55.2% and 82.8% to ET, 75% and 91.7% to dementia.

Conclusions

The high sensitivity of the test could be employed as a valuable screening tool. But TCS is more useful as a supplementary diagnostic method, due to the specificity values not being comprehensive.

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.

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.

Transcranial brain sonography in Parkinson's disease with restless legs syndrome

Substantia nigra (SN) hyperechogenicity assessed by transcranial brain sonography (TCS) is a characteristic finding in idiopathic Parkinson's disease (PD). In contrast, SN hypoechogenicity on TCS has been recently demonstrated in restless legs syndrome (RLS). RLS is one of the most common sleep problems in PD, but the pathophysiologic relationship between these two disorders has not been thoroughly elucidated. We compared the SN echogenicities of PD patients with and without RLS to investigate whether comorbid RLS in PD affects SN echogenicity and to explain the echogenic differences between idiopathic RLS (iRLS) and secondary PD-related RLS (pRLS). Sixty-three PD patients (median age 64.6 +/- 10.6 years), 40 iRLS patients (53.1 +/- 11.7 years), and 40 healthy controls (69.1 +/- 2.3 years) were enrolled in our study. All subjects answered a sleep questionnaire and underwent TCS. PD patients were subdivided into two groups, PD with RLS (PD+RLS, n = 26) and PD without RLS (PD-RLS, n = 37), and the sonographic findings of each group were compared. Although significant hyperechogenicity was detected in both the SN and SN/midbrain ratios in both PD subgroups compared with the controls and the iRLS group (P < 0.001), there were no significant differences in SN echogenicity between the PD+RLS and PD-RLS groups. Meanwhile, iRLS patients showed significant SN hypoechogenicity. In conclusion, comorbid RLS in PD did not have an impact on the sonographic SN findings. These results suggest that the pathogenesis of pRLS and iRLS involve different mechanisms. Further study will be required to clarify the association between RLS and PD.

Transcranial sonography findings related to non-motor features of Parkinson's disease

Transcranial sonography (TCS) allows high resolution imaging of deep brain structures, provided sufficient imaging conditions and adequate qualification of the investigator. Since TCS can display changes of midbrain structures and basal ganglia that are not or only heavily detected with other neuroimaging methods, TCS has yielded new insights into the pathogenesis also of non-motor features of PD. Abnormal increased echogenicity ('hyperechogenicity') of substantia nigra is not only a characteristic finding in PD, but is also related to increased risk of depression in PD patients (relative risk [RR], 1.9). Reduced echogenicity ('hypoechogenicity') of midbrain raphe indicated increased risk of depression (RR, 2.0) and urinary incontinence (RR, 4.7) in PD patients. Caudate nucleus hyperechogenicity was associated with drug-induced psychosis (RR, 2.4), and frontal-horn dilatation >20mm with dementia (RR, 3.6). TCS findings support the hypothesis of a pathogenetic link between depression and PD. Further studies are warranted to find out whether TCS is useful for detecting increased risk for non-motor complications, such as depression, psychosis, or urinary incontinence, already before they become clinically obvious.

Transcranial duplex in the differential diagnosis of parkinsonian syndromes: a systematic review

BACKGROUND

Transcranial duplex scanning (TCD) of the substantia nigra (SN) is increasingly used to diagnose Idiopathic Parkinson's Disease (IPD). Up until now 70 diagnostic studies have been published, not only on investigation of the SN, but also of the lenticular nucleus (LN) and the Raphe nuclei (RN).

METHOD

We systematically reviewed all diagnostic TCD studies in parkinsonian patients up to June 2008.

RESULTS

We found 35 eligible studies. Of the 1534 IPD patients investigated in the 35 studies 200 (13%) had an inconclusive SN-TCD. An increased echo-intensity of the SN was seen in 1167 (87%) of the 1334 IPD patients, 276 (12%) of the 2340 healthy controls and in 41 (30%) of the 138 patients with an atypical parkinsonian syndrome (APS). On the contrary, a pathological LNTCD was found more often in APS patients (79%) than in IPD patients (23%) and healthy controls (6%). A decreased echo-intensity of the RN was found more often in depressed (46%) than in non-depressed IPD patients (16%).

CONCLUSIONS

SN-TCD accurately differentiates between patients with IPD and healthy controls, but not between patients with IPD and APS. LN-TCD is only moderate accurate to delineate IPD from APS, but combinations of SN- and LN-TCD may be more promising. RN-TCD has only marginal diagnostic accuracy in diagnosing depression in IPD and non-IPD patients. Before TCD can be implicated, more research is needed to standardize the TCD technique, to investigate the TCD in non-research settings and to determine the additional value of TCD compared with currently used clinical techniques like SPECT imaging.