Sensory trick in upper limb dystonia

Introduction: Sensory trick is a specific maneuver that temporarily improves dystonia that is usually observed in 44%–89% of patients with cranial-cervical dystonia and in 20% of patients with upper limb dystonia. This study aimed to assess the prevalence of sensory trick in a cohort of 37 patients with idiopathic adult-onset upper limb dystonia and to determine whether sensory trick can be a useful tool to distinguish dystonic and non-dystonic tremor. Methods: Thirty-seven right-handed patients with idiopathic upper limb dystonia and disturbed handwriting and 19 patients with non-dystonic action tremor in the upper limb causing writing disturbances participated into the study. Patients were asked to write a standard sentence twice, before and after applying a standardized sensory trick (gently grabbing right wrist with his left hand). Readability of the two sentences was assessed by three observers blinded to diagnosis. Results: Five/37 patients (13%) self-discovered ST over disease history, while performing the standardized trick maneuver improved handwriting in 14/37 patients (38%). Interobserver agreement on the effectiveness of sensory trick among the three observers yielded a kappa value of 0.86 (p < 0.0001). The standardized trick was effective in 8/19 patients with dystonic tremor (42%) and in 0/19 patients with non-dystonic tremor (p = 0.003). Conclusion: The results of applying a standardized non-spontaneous trick demonstrated that, in upper limb dystonia, ST may be more frequent than usually observed. Effective sensory trick, when present, may be a hallmark of idiopathic dystonia. The lack of effective sensory trick may help to identify non dystonic upper limb tremor

Gender differences in olfactory function in patients with Parkinson's disease.

Introduction: Previous studies reported the presence of gender-related differences in motor and non motor symptoms in patients affected by Parkinson's disease (PD) (1, 2). However, gender-related differences in olfactory function are not clearly investigated. Objective: To assess the presence of gender-related differences in olfactory function among patients with PD compared to age and sex matched healthy controls. Methods: One hundred and sixty eight participants were enrolled (99 PD patients, 57 males and 42 females and 69 healthy controls, 31 males and 38 females). Olfactory function was evaluated with odor threshold, discrimination, identification and their sum TDI score by the Sniffin’ Sticks tests (3). The Montreal Cognitive Assessment (MoCA) was used to assess cognitive impairment. Apathy was examined by the Starkstein Apathy Scale (SAS) and fatigue was evaluated by the Parkinson’s Disease Fatigue Scale (PFS). Data are presented as mean values ± standard error mean. Results: Male PD patients showed a significant impairment compared to female PD patients in odor discrimination (8.4 ± 0.420 vs 7.1 ± 0.408, p<0.05), odor identification (8.6 ± 0.454 vs 7 ± 0.420, p<0.05) and in TDI score (19.9 ± 0.920 vs 16.73 ± 0.919, p<0.05). As regards odor threshold, no significant differences were observed between males and females. Moreover, no gender related differences were observed in olfactory function among healthy controls. Multivariate linear regression analyses showed that apathy and gender were the most important predictors related to the impairment of olfactory function in PD patients. Conclusions: A specific gender difference in olfactory dysfunctions among PD patients were observed only for odor discrimination, identification and TDI score. These findings highlighted the possible role of gender differences in the development of associated PD non motor symptoms. References 1) Solla et al. J Neurol Sci. 2012. 323(1-2):33-9 2) Picillo et al. J Neurol. 2013. 260(11):2849-55 3) Hummel et al. Eur Arch Otorhinolaryngol. 2007. 264(3):237–243

Role of dopaminergic neurotransmission in pathophysiology of action tremor in Parkinson's disease

Rest tremor (RT), a tremor that occurs in a body part that is completely supported against gravity, is together with rigidity and bradykinesia among the core features of Parkinson's disease (PD). In addition to classical RT, many PD patients also have action tremor (AT) occurring during sustained postures or voluntary movement. Earlier studies showed a good correlation between striatal dopamine transporter (DAT) binding, measured with [(123)I] FP-CIT SPET and bradykinesia. By contrast, neither rigidity nor rest tremor seems to be closely related to the degree of dopaminergic denervation as measured by DAT imaging. Little is known about the relationship, if any, between the severity of action tremor and striatal DAT binding