Neurological research in Italy from 2020 to 2023.

BACKGROUND: To assess the state of neurological scientific research in Italy in the time interval 2020-2023. METHODS: Elsevier's modular integrated platform "SciVal" was used to analyze bibliometric research products starting from scientific production data uploaded onto Scopus. We considered the research area "Neurology" in the 01/01/2020-14/06/2023 time interval, and the following variables were extracted: number of published studies, number of citations, Field-Weighted Citation Impact, and percentage of international collaborations. The contribution of Italian scientists to the neurological research was compared to that of the other nations. RESULTS: Research identified 90,633 scientific papers in the neurological area worldwide, with a total of 472,750 citations. The products assigned to Italian groups were 6670 (53,587 citations, Field-Weighted Citation Impact 1.68, 41% international collaborations). CONCLUSIONS: According to the present study, Italian neurological research 2020 to 2023 ranks fifth globally and third in Europe.

Neurological phenomenology of the IRF2BPL mutation syndrome: Analysis of a new case and systematic review of the literature.

BACKGROUND: IRF2BPL is an intronless gene that was mapped to 14q24.3 chromosome in 2000 and codes for the interferon regulatory factor 2 binding like protein. OBJECTIVE: To analyses the clinical characteristics of the patients reported in the literature and of an additional patient we observed in order to better delineate the phenomenological spectrum of the disease and provide indications to improve clinical recognition and facilitate diagnosis. METHODS: We reported on 28 patients carrying the IRF2BPL mutation who were identified in 10 papers (n.27), using PUBMED as the search engine, and in our hospital (n. 1). RESULTS: All patients shared developmental delay/regression. Additional neurological symptoms were present in a large proportion of patients and reflected the involvement of five main neurological domains, i.e. epilepsy, dystonia, ataxia, spasticity, and ocular disturbances. Correlation analysis suggested a significant positive correlation between the number of affected neurological domains and the presence of MRI abnormalities (rho = 0.45, p = 0.02), while no significant correlation emerged between the number of affected clinical domains and age at disease onset (rho = 0.18, p = 0.35) or variant type (rho = 0.30, p = 0.12). CONCLUSIONS: Our analysis highlights that the IRF2BPL mutation syndrome is highly specific to the central nervous system. Diagnostic work-up should consider the clinical picture of the IRF2BPL mutation syndrome herein delineated and the existence of conditions that share developmental delay/regression and result from acquired/genetic or unidentifiable underlying etiology.

A "Catastrophic" Heparin-Induced Thrombocytopenia.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a transient, antibody-mediated thrombocytopenia syndrome that usually follows exposure to unfractioned heparin (UFH) or low-molecular-weight heparin (LMWH). In contrast to other pathological conditions which lead to thrombocytopenia and bleeding complications, HIT results in a paradoxical prothrombotic state. It is caused by antibodies directed to complexes containing UFH or LMWH and a self-platelet protein: the platelet factor 4 (PF4). The heparin-PF4 immune complex leads to activation of platelets, monocytes, and endothelial cells which release procoagulant proteins and tissue factor with subsequent blood coagulation activation. Case Report. We describe the case of a woman undergone to knee replacement and affected by urosepsis who developed a HIT after exposure to enoxaparin. The thrombotic burden was very impressive involving the arterial and venous cerebral vessel and the venous pulmonary, hepatic, and inferior legs vascular beds. The patient was successfully treated with fondaparinux without recurrent thrombosis or bleeding. The clinical scenario could be named "catastrophic HIT" like the catastrophic antiphospholipid syndrome since they have a similar pathogenetic mechanism involving both platelets and monocytes procoagulant activities and a similar clinical manifestation with a life-threatening multiple arterial and/or venous thromboses. CONCLUSION: Patients presenting with HIT could show a very impressive thrombotic burden resembling to that of the catastrophic antiphospholipid syndrome. A careful differential diagnosis should be made towards other pathological conditions which lead to thrombocytopenia to avoid an unnecessary and potentially harmful platelet transfusion. Although fondaparinux is off-label, its use in patients with HIT is simple and seems to be effective.

Efficacy and safety of 5-hydroxytryptophan on depression and apathy in Parkinson's disease: a preliminary finding.

BACKGROUND AND PURPOSE: Several studies have indicated that altered serotonergic neurotransmission may contribute to non-motor features commonly associated with Parkinson's disease (PD) such as apathy and depression. 5-hydroxytryptophan (5-HTP) is the intermediate metabolite of L-tryptophan in the production of serotonin. To date, there has been inconsistent research on the use of 5-HTP in PD. The purpose of this study was to compare the effects of 5-HTP with those of placebo on apathy and depressive symptoms in patients with PD. METHODS: A single-center, randomized, double-blind placebo-controlled cross-over trial was employed; 25 individuals were subsequently enrolled into the study. Patients received placebo and 50 mg of 5-HTP daily over a period of 4 weeks. For the assessment of efficacy on depressive and apathy symptoms the Beck Depression Inventory-II (BDI-II), Hamilton Depression Rating Scale (HDRS) and Apathy Scale (AS) were respectively administered at screening, baseline and weeks 4, 8, 12 and 16. Primary efficacy outcomes were the comparison of 5-HTP to placebo in mean change from baseline to weeks 4, 8, 12 and 16 in total score on the AS, BDI-II and HDRS. RESULTS: Repeated-measures analysis revealed a significant improvement of depressive symptoms during the 50-mg 5-HTP treatment compared with placebo as assessed by the HDRS. No effect of 5-HTP was seen on apathy symptoms assessed by the AS. CONCLUSIONS: This study provides preliminary evidence of clinical benefit of 5-HTP for treating depressive symptoms in PD. Larger studies with a longer treatment duration are needed to corroborate these early findings.

Sex-related differences in olfactory function and evaluation of possible confounding factors among patients with Parkinson's disease.

The role of specific sex-related patterns in olfactory dysfunctions of Parkinson's disease (PD) patients is unclear. The aim of this study was to assess the presence of specific sex-related patterns in olfactory dysfunctions excluding the possibility of confounding effects in patients with Parkinson's disease. One hundred and sixty-eight participants (99 PD patients and 69 controls) were enrolled and evaluated using Sniffin' Sticks Extended test (SSET). There was no significant sex difference in the control group for the SSET parameters. By contrast, in the PD group male patients scored significantly lower on odor discrimination (OD), identification (OI), and Threshold-Discrimination-Identification (TDI) score than females. On multivariable linear regression analysis, the only significant predictors of TDI score were sex and apathy. Among PD patients, men showed a significantly greater impairment compared to women in OI, OD and TDI score, but not in odor threshold (OT). These findings highlighted the possible role of sex differences in the development of associated PD non-motor symptoms.

Disease progression in blepharospasm: a 5-year longitudinal study.

BACKGROUND AND PURPOSE: The clinical manifestation of dystonic spasms in blepharospasm (BSP) patients may be heterogeneous. Whether the varying phenomenology of eyelid spasms becomes manifest sequentially during the course of the disease or aggregates in separate clusters according to different disease courses is still unclear. For this purpose, the clinical features in BSP patients were evaluated longitudinally over a 5-year period and also the blink reflex recovery cycle was tested in a subgroup of BSP patients. METHODS: Sixty BSP patients were videotaped at time 0 and after approximately 5 years of follow-up. Two experts in movement disorders, who were blinded to the video order, reviewed the videotapes and scored the severity of BSP using the Blepharospasm Severity Rating Scale. Changes in the R2 recovery index were also evaluated in 18 patients twice, i.e. upon enrolment and at the follow-up. RESULTS: The severity of BSP worsened significantly over the 5-year follow-up period owing to the appearance or the increased duration and frequency of prolonged spasms. It was also found that the blink reflex recovery cycle worsened at follow-up in comparison with the baseline. CONCLUSIONS: This study shows that the disease progression of BSP is characterized by the appearance or worsening of prolonged spasms. Prolonged spasms are accompanied by changes in the excitability of brainstem interneurons. Aging-related effects may exacerbate the pathophysiological mechanisms underlying spasms.

Spread of dystonia in patients with idiopathic adult-onset laryngeal dystonia.

BACKGROUND AND PURPOSE: Adult-onset laryngeal dystonia (LD) can be isolated or can be associated with dystonia in other body parts. Combined forms can be segmental at the onset or can result from dystonia spread to or from the larynx. The aim of this study was to identify the main clinical and demographic features of adult-onset idiopathic LD in an Italian population with special focus on dystonia spread. METHODS: Data were obtained from the Italian Dystonia Registry (IDR) produced by 37 Italian institutions. Clinical and demographic data of 71 patients with idiopathic adult-onset LD were extracted from a pool of 1131 subjects included in the IDR. RESULTS: Fifty of 71 patients presented a laryngeal focal onset; the remaining subjects had onset in other body regions and later laryngeal spread. The two groups did not show significant differences of demographic features. 32% of patients with laryngeal onset reported spread to contiguous body regions afterwards and in most cases (12 of 16 subjects) dystonia started to spread within 1 year from the onset. LD patients who remained focal and those who had dystonia spread did not show other differences. CONCLUSIONS: Data from IDR show that dystonic patients with focal laryngeal onset will present spread in almost one-third of cases. Spread from the larynx occurs early and is directed to contiguous body regions showing similarities with clinical progression of blepharospasm. This study gives a new accurate description of LD phenomenology that may contribute to improving the comprehension of dystonia pathophysiology.

Correlation among olfactory function, motors' symptoms, cognitive impairment, apathy, and fatigue in patients with Parkinson's disease.

Although Parkinson's disease (PD) is usually considered as a movement disorder, it is strongly associated with non-motor symptoms (NMS), including smell and taste dysfunctions, cognitive impairment, apathy, fatigue, and autonomic dysregulation. Olfactory deficit is considered the most common NMS in PD preceding the motor symptoms for years. The aim of this study was to investigate olfactory function, cognitive impairment, apathy, and fatigue in patients with PD in comparison with healthy controls, and subsequently to analyse the correlations between these NMS and motor symptoms severity in subjects with PD. One hundred and forty-seven participants were enrolled (96 PD patients, mean age in years 67.5, SD 7.2; 51 healthy controls; mean age 65.1, SD 11.8). Olfactory function was evaluated using the Sniffin' Sticks test (odor detection threshold, discrimination and identification). The Montreal Cognitive Assessment (MoCA) was used to assess cognitive impairment. Apathy was examined by the self-report version of Starkstein Apathy Scale and fatigue was evaluated with the Parkinson's Disease Fatigue Scale. PD patients showed severe impairment in odor detection threshold, discrimination, and identification compared to healthy controls. Moreover, in PD patients, apathy and fatigue scores were significantly increased, while MoCA scores were decreased in comparison with controls. Multivariate linear regression analyses showed that both apathy and Unified PD Rating Scale (UPDRS) were associated with odor identification, discrimination and Threshold-Discrimination-Identification (TDI) score. In conclusion, our results reported changes in apathy and motor disability as significant predictors in alterations of odor identification, discrimination and TDI score. Furthermore, these data suggest that olfactory dysfunction might progress in tight relation with motor impairment UPDRS but also with non-motor symptoms such as apathy.

Pain in focal dystonias - A focused review to address an important component of the disease.

Focal dystonia is characterized by involuntary muscle contractions that cause abnormal postures and/or twisting movements in a segment of the body. Motor symptoms have a major impact on disability in this condition, but the presence of pain represents an additional source of impairment and poor quality of life. Notwithstanding that pain occurs in up to 70% of patients with cervical dystonia and in a relevant proportion of subjects with focal dystonia of the limbs, it has received very little attention from researchers and controlled trials are scant. The aim of this review is to summarize the current knowledge on the clinical assessment and management of pain in focal dystonias. The search results will inform on the types of pain reported in focal dystonias, on the tools that are used to quantify pain and on the efficacy of pharmacological and non-pharmacological approaches. The collated data will hopefully improve the clinical management of focal dystonia and also stimulate future research on dystonia-associated pain. Optimization of the outcome indeed requires the identification and the management of all the factors that determine disability and hence relies on a multidisciplinary approach.

Pain in Parkinson's disease: facts and uncertainties.

Pain is one of the most common and troublesome non-motor symptoms of Parkinson's disease (PD). It can appear at any time during the disease and is often present before diagnosis. However, there is little or no consensus on its definition. An expert group of clinicians with relevant research experience met to review the existing evidence and to identify gaps in our understanding leading towards AUTHOR: 'understanding towards' has been changed to 'understanding leading towards'. Please check and confirm that this is appropriate an optimized therapy of pain in PD. Key findings from epidemiologic, neurophysiologic, neuroimaging and clinical studies are reviewed. In each case, the evidence base is limited by wide variations in the definitions of pain applied, study methodologies and populations evaluated. Disease-related and medical conditions trigger spontaneous pain in patients with PD, which is then abnormally processed and results in painful manifestations in specific body parts. Dopaminergic medications, such as rotigotine, as well as opiate analgesics, such as oxycodone, have shown positive results but future studies with more detailed pain characterization at inclusion are warranted.

Relationship between pain and motor and non-motor symptoms in Parkinson's disease.

BACKGROUND AND PURPOSE: Although female gender, depressive symptoms and medical conditions predisposing to pain are more common in patients with Parkinson's disease (PD) with pain, no study has yet explored the relationship between pain and other non-motor symptoms (NMS). METHODS: A total of 321 consecutive patients with PD [190 men/131 women aged 68.3 (SD 9.2) years] attending four Italian movement disorder clinics were studied. Demographic/clinical data were obtained by a standardized interview and the NMS scale. The association of pain with motor and NMS was assessed by multivariable logistic regression models. RESULTS: At the time of the study, 180 patients with PD (56%) reported chronic pain that, in most cases, was described as being muscular or arthralgic pain. Pain preceded the onset of motor signs in 36/180 patients. In the main-effect model, factors independently associated with pain were female sex [odds ratio (OR), 2.1; P = 0.01], medical conditions predisposing to pain (OR, 2.9; P < 0.001), Hoehn-Yahr staging (OR, 1.9; P = 0.04), motor complications (OR, 4.7; P = 0.04) and NMS belonging to the sleep/fatigue (OR, 1.6; P = 0.04) and mood/cognition (OR, 1.6; P = 0.03) domains. Most explanatory variables in the multivariable analysis were similarly distributed in patients in whom pain may have been related to PD or to a cause other than PD. CONCLUSIONS: We confirm that pain in PD is more frequent in women and in subjects with medical conditions predisposing to painful symptoms. Moreover, this strengthens the association between pain and motor severity measures and NMS domains, particularly sleep and mood disturbances.

Clinical heterogeneity in patients with idiopathic blepharospasm: A cluster analysis.

BACKGROUND: Idiopathic blepharospasm is a clinically heterogeneous condition. It is not known whether the various manifestations become manifest sequentially during the course of the disease or aggregate in separate clusters identifying subpopulations of patients. METHODS: Eighty-nine patients with idiopathic blepharospasm were assessed using k-means cluster analysis to identify relatively homogeneous groups on the basis of low-intragroup/high-intergroup differences across a set of selected variables. RESULTS: The results suggest that there may be three groups of patients. Group 1 included patients who had prolonged muscle spasms leading to complete rim closure associated with brief and/or prolonged spasms with incomplete rim closure, the most severe blepharospasm, and a greater tendency to spread to adjacent segments. Group 2 included patients characterized by prolonged spasms with partial rim closure, either alone or associated with brief spasms whereas Group 3 included patients with brief spasms with complete rim closure, the least severe blepharospasm, and the lowest tendency to spread. The severity of Group 2 blepharospasm was between that observed in Group 1 and Group 3, while the tendency to spread was similar to Group 3. The three groups did not differ for disease duration, age of onset, sex and other clinical features. The observation that inhibition of the R2 component of the blink reflex recovery cycle was more abnormal in Groups 1/2 2 than in Group 3 at least in part validates our classification. CONCLUSIONS: The present study suggests that blepharospasm patients may be classified in different subtypes according to the type of spasms, severity of the condition and tendency to spread.

BDNF and LTP-/LTD-like plasticity of the primary motor cortex in Gilles de la Tourette syndrome.

Gilles de la Tourette syndrome (GTS) is characterized by motor and vocal tics and often associated with obsessive-compulsive disorder (OCD). Responses to intermittent/continuous theta-burst stimulation (iTBS/cTBS), which probe long-term potentiation (LTP)-/depression (LTD)-like plasticity in the primary motor cortex (M1), are reduced in GTS. ITBS-/cTBS-induced M1 plasticity can be affected by brain-derived neurotrophic factor (BDNF) polymorphism. We investigated whether the BDNF polymorphism influences iTBS-/cTBS-induced LTP-/LTD-like M1 plasticity in 50 GTS patients and in 50 age- and sex-matched healthy subjects. In GTS patients, motor and psychiatric (OCD) symptom severity was rated using the Yale Global Tic Severity Scale (YGTSS) and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). We compared M1 iTBS-/cTBS-induced plasticity in healthy subjects and in patients with GTS. We also compared responses to TBS according to BDNF polymorphism (Val/Val vs Met carriers) in patients and controls. Fourteen healthy subjects and 13 GTS patients were Met carriers. When considering the whole group of controls, as expected, iTBS increased whereas cTBS decreased MEPs. Differently, iTBS/cTBS failed to induce LTP-/LTD-like plasticity in patients with GTS. When comparing responses to TBS according to BDNF polymorphism, in healthy subjects, Met carriers showed reduced MEP changes compared with Val/Val individuals. Conversely, in patients with GTS, responses to iTBS/cTBS were comparable in Val/Val individuals and Met carriers. YGTSS and Y-BOCS scores were comparable in Met carriers and in Val/Val subjects. We conclude that iTBS and cTBS failed to induce LTP-/LTD-like plasticity in patients with GTS, and this was not affected by BDNF genotype.

Rest tremor in idiopathic adult-onset dystonia.

BACKGROUND: Tremor in dystonia has been described as a postural or kinetic abnormality. In recent series, however, patients with idiopathic adult-onset dystonia also displayed rest tremor. METHODS: The frequency and distribution of rest tremor were studied in a cohort of 173 consecutive Italian patients affected by various forms of idiopathic adult-onset dystonia attending our movement disorder clinic over 8 months. RESULTS: Examination revealed tremor in 59/173 patients (34%): 12 patients had head tremor, 34 patients had arm tremor, whilst 13 patients presented tremor in both sites. Head tremor was postural in all patients, whereas arm tremor was postural/kinetic in 28 patients, only at rest in one and both postural/kinetic and at rest in 18 patients. Patients with tremor were more likely to have segmental/multifocal dystonia. Patients who had rest tremor (either alone or associated with action tremor) had a higher age at dystonia onset and a greater frequency of dystonic arm involvement than patients with action tremor alone or without tremor. CONCLUSIONS: Both action and rest tremor are part of the tremor spectrum of adult-onset dystonia and are more frequently encountered in segmental/multifocal dystonia. The higher age at dystonia onset and the greater frequency of arm dystonia in patients with rest tremor may have pathophysiological implications and may account, at least in part, for the previous lack of identification of rest tremor as one possible type of tremor present in dystonia.

Smoking in Patients with Parkinson's Disease: preliminary striatal DaT-SPECT findings.

OBJECTIVE: To assess whether cigarette smoking interferes with dopaminergic transmission in current- and never-smoking patients with Parkinson's disease. MATERIALS AND METHODS: Striatal [123I]FP-CIT single photon emission computed tomography was performed in 67 patients with Parkinson's disease (35 women and 32 men aging 60.8 ± 10.1 years and staging 1.76 ± 0.5 on the Hoehn and Yahr scale). At study time, there were 13 current-smokers and 54 never-smokers. RESULTS: Current-smokers showed a significantly lower putamen/occipital [123I]FP-CIT ratio and a non-significant trend to a lower caudate/occipital [123I]FP-CIT ratio uptake. Current-smokers were also characterized by a lower off UPDRS-III motor score. A logistic regression analysis adjusted for age, sex, disease duration, Hoehn and Yahr staging, and medication indicated a significant lower [123I]FP-CIT uptake not only in the putamen (odds ratio, 0.1; 95% confidence interval, 0.01 to 0.65; P = 0.02) but also in the caudate (odds ratio, 0.2; 95% confidence interval, 0.04 to 0.71; P = 0.015) as well as a lower UPDRS-III motor score (odds ratio, 0.9; 95% confidence interval, 0.81 to 0.99; P = 0.04) in current-smokers. CONCLUSIONS: The lower [123I]FP-CIT uptake together with the lower UPDRS-III motor score observed in our current-smokers patients with Parkinson's disease (even taking into account variables that are probably expression of dopaminergic neuron decline and treatment) would support an effect of smoking on dopaminergic synaptic mechanisms.

Diagnostic delay in adult-onset dystonia: data from an Italian movement disorder center.

Adult-onset dystonia (AOD) may manifest in focal forms (as blepharospasm, oromandibular dystonia, cervical dystonia, laryngeal dystonia, and hand dystonia) or in segmental forms. Time from onset of dystonia to diagnosis can be an indicator of the quality of care received during the diagnosis of AOD, likely reflecting factors associated with both the patient and their health system. Three previously reported single-center studies showed that diagnosis of AOD may be delayed for several years. Here, we examined the time lapse between onset and diagnosis in patients with different forms of AOD from an Italian movement disorder center. We found the time lapse between dystonia onset and diagnosis was very long for patients who developed AOD before 1980; and even in the most recent years reaching a correct diagnosis required more than year in almost half of cases. Our results suggest that the delay in diagnosis of adult-onset focal and segmental dystonia has improved over time, but remains unacceptable. The findings are a promising indicator of improvements in care of this uncommon disorder. However, education of patients and doctors is still needed.

Action tremor in Parkinson's disease: frequency and relationship to motor and non-motor signs.

BACKGROUND AND PURPOSE: Action tremor may occur in patients with Parkinson's disease and cause misdiagnosis with other movement disorders such as essential tremor and dystonia. Data on the frequency of action tremor in Parkinson's disease and on the relationships with other motor and non-motor signs are limited. METHODS: A cross-sectional study of 237 patients with Parkinson's disease staging 1-2 on the Hoehn-Yahr scale was conducted. Data on action tremor and other motor and non-motor signs were collected using the Unified Parkinson's Disease Rating Scale part III and the Non-Motor Symptoms Scale. RESULTS: Action tremor was found in 46% of patients and was associated with both severity of rest tremor (adjusted odds ratio 3.0, P < 0.001) and severity of rigidity (adjusted odds ratio 1.5, P = 0.004). No association was found between action tremor and severity of bradykinesia (adjusted odds ratio 0.97, P = 0.4) or axial symptoms (adjusted odds ratio 0.9, P = 0.3). Moreover, patients who had action tremor reported a significant lower mean number of non-motor symptoms than those who had not (2.1 ± 1.3 vs. 2.4 ± 1.3; P = 0.04). CONCLUSIONS: Action tremor is a relatively frequent motor sign in patients with Parkinson's disease staging 1-2 on the Hoehn-Yahr scale. Action tremor correlates with rest tremor and rigidity and may be associated with a lower burden of non-motor symptoms. These findings suggest a contribution of non-dopaminergic mechanisms to action tremor pathophysiology.

How pain arises in Parkinson's disease?

In recent years, increasing attention has centred on pain in Parkinson's disease (PD). Pain in PD is heterogeneous in quality and body distribution. To clarify how the various pain types relate to PD and to propose plausible treatment strategies, in this paper we reviewed psychophysical, neurophysiological and imaging data reported in parkinsonian patients with and without pain. Most available evidence supports abnormal central nociceptive input processing that probably reflects an impairment in the lateral and medial pain pathways. Changes in central pain processing probably underlie all the different pain types and also intervene in patients with PD without pain. Thus, altered pain processing might predispose patients with PD to spontaneous pain that is variable in quality. These background pain-processing abnormalities may interact with additional factors (such as contractures secondary to marked rigidity/bradykinesia, dystonia and medical conditions associated with painful symptoms), thus causing pain to manifest itself clinically in various ways and providing candidate targets for pain treatment in PD.

Abnormal tactile temporal discrimination in psychogenic dystonia.

OBJECTIVE: Neurophysiologic studies demonstrated that patients with primary torsion dystonia (PTD) and with psychogenic dystonia (Psy-D) share similar abnormalities in the motor system. In this study, we evaluated somatosensory function in Psy-D by testing temporal discrimination threshold (TDT), and compared the results with those obtained in patients with PTD. METHODS: TDT of tactile stimuli was assessed in 10 patients with Psy-D, 10 patients with PTD, and 16 control subjects. The 2 groups of patients were matched for age, gender, disease duration, and distribution of dystonia. Tactile stimuli consisted of pairs of non-noxious electrical shocks delivered to the right or left hand at interstimulus interval increasing from 0 to 400 msec, in 10-msec steps. TDT was defined as the value at which subjects recognized the 2 stimuli as asynchronous. RESULTS: TDT was higher in Psy-D and PTD compared to control subjects, for both the right and the left hand. In a subgroup of patients with unilateral dystonia (Psy-D = 4, PTD = 5), TDT did not differ between the affected and the unaffected side in both groups of patients. Disease duration was not correlated to the increased TDT value. CONCLUSIONS: Our study suggests an impaired processing of somatosensory inputs in both Psy-D and PTD. These abnormalities might represent a neurophysiological trait predisposing to develop a dystonic posture triggered by psychiatric and psychological factors.