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

Abstract

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 mm 2 (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.

Neurosonological Findings Related to Non-Motor Features of Parkinson’s Disease: A Systematic Review

“…They reported, for the first time, that the SN echogenic area in PD patients with visual hallucinations (VH) was significantly higher than in those without VH. This finding was constant after adjusting by age, disease duration, and Minimental State Examination and UPDRS scores [33].…”

“…Another interesting finding of Li et al [33] involving SN hyperechogenicity was its relationship with the presence of VH, evaluated with the PD-NMSQ. The exact pathogenesis of VH in PD patients is not clearly understood.…”

“…This finding was independent from PD duration. More recently, Li et al [33] compared the TCS findings in a group of 111 PD patients and 61 non-PD controls, evaluating the presence of NMS with the PD-NMSQ, the Parkinson's disease sleep scale, addressing sleep and nocturnal disability [38], the constipation severity instrument [39], and the Parkinson's disease Fatigue Scale [40]. They reported, for the first time, that the SN echogenic area in PD patients with visual hallucinations (VH) was significantly higher than in those without VH.…”

“…BR hypoechogenicity was more pronounced in subjects with longer duration of urinary symptoms, with no other differences identified in the rest of the analyzed structures. Other authors evaluated the relation of midbrain transcranial structures and autonomic specific items in the Non-Motor Symptoms Questionnaire for patients with PD (PD-NMSQ), as well as the Scale for Outcomes in PD, autonomic symptoms (SCOPA-AUT) [32,33]. The PD-NMSQ consists of 30 items that address nine domains including gastrointestinal, cardiovascular, and urinary symptoms, sexual function, cognition (apathy, attention, memory), presence of hallucinations, depression or anxiety, sleep disorders, pain, and fatigue [34].…”

“…The SCOPA-AUT includes 25 items assessing autonomic symptoms: gastrointestinal, urinary, cardiovascular, thermoregulatory, pupillomotor, and sexual dysfunction [35]. None of the included studies reported any relevant relation between PD-NMSQ and SCOPA-AUT scores and the US findings [32,33].…”