Abnormal sensory gating in patients with different types of focal dystonias.

BACKGROUND: Movement execution in healthy individuals increases the somatosensory temporal discrimination threshold. These changes are a result of mechanisms of sensory gating at the subcortical level. Although the somatosensory temporal discrimination threshold is abnormally increased in patients with focal dystonias, the effect of movement execution on somatosensory temporal discrimination in dystonic patients is unknown. OBJECTIVES: The objective of this study was to determine whether somatosensory temporal discrimination threshold modulation induced by voluntary movement is normal in different forms of focal dystonia. METHODS: We enrolled 71 dystonic patients (24 with blepharospasm, 31 with cervical dystonia, and 16 with focal hand dystonia) and 39 age-matched healthy participants. Paired stimuli for the somatosensory temporal discrimination threshold were triggered by movement execution at movement onset and at various time intervals thereafter. We analyzed the kinematic features of the motor task to ascertain whether tactile input induces changes in movement parameters. RESULTS: Movement execution led to greater and longer lasting increases in somatosensory temporal discrimination threshold values, both upon movement onset and at various time intervals thereafter, in patients with cervical dystonia and focal hand dystonia than in those with blepharospasm or the healthy participants. Somatosensory temporal discrimination testing did not induce any changes in the mean velocity of index finger movements in either patients or healthy participants. CONCLUSIONS: Somatosensory temporal discrimination threshold changes induced by movement execution are abnormal in focal dystonias. This abnormality is related to the type of dystonia. Abnormal gating of sensory information is likely involved in movement-induced triggering or worsening of different forms focal dystonia. © 2018 International Parkinson and Movement Disorder Society.

Current Clinical Psychopharmacology in Borderline Personality Disorder.

BACKGROUND: Patients with Borderline Personality Disorder (BPD) manifest affective and behavioral symptoms causing personal distress, relationship difficulties, and reduced quality of life with global functioning impairment, mainly when the disease takes an unfavorable course. A substantial amount of healthcare costs is dedicated to addressing these issues. Many BPD patients receive medications, mostly those who do not respond to psychological interventions. OBJECTIVE: Our aim was to assess the efficacy of the most used strategies of pharmacological interventions in BPD with a comprehensive overview of the field. METHODS: We searched the PubMed database for papers focused on the most used psychotropic drugs for BPD. We included randomized controlled trials and open studies in adult patients with BPD, focusing on the efficacy and tolerability of single classes of drugs with respect to specific clinical presentations that may occur during the course of BPD. RESULTS: Specific second-generation antipsychotics (SGAs) or serotonergic antidepressants can be effective for different core symptoms of BPD, mainly including mood symptoms, anxiety, and impulse dyscontrol. Some atypical antipsychotics can also be effective for psychotic and dissociative symptoms. Specific antiepileptics can be useful in some cases in treating different BPD symptoms, mainly including mood instability, impulsiveness, and anger. CONCLUSION: No medication is currently approved for BPD, and clinicians should carefully assess the benefits and risks of drug treatment. Further studies are needed to identify specific personalized treatment strategies, also considering the clinical heterogeneity and possible comorbidities of BPD.

Voluntary Movement Takes Shape: The Link Between Movement Focusing and Sensory Input Gating.

The aim of the study was to investigate the relationship between motor surround inhibition (mSI) and the modulation of somatosensory temporal discrimination threshold (STDT) induced by voluntary movement. Seventeen healthy volunteers participated in the study. To assess mSI, we delivered transcranial magnetic stimulation (TMS) single pulses to record motor evoked potentials (MEPs) from the right abductor digiti minimi (ADM; "surround muscle") during brief right little finger flexion. mSI was expressed as the ratio of ADM MEP amplitude during movement to MEP amplitude at rest. We preliminarily measured STDT values by assessing the shortest interval at which subjects were able to recognize a pair of electric stimuli, delivered over the volar surface of the right little finger, as separate in time. We then evaluated the STDT by using the same motor task used for mSI. mSI and STDT modulation were evaluated at the same time points during movement. mSI and STDT modulation displayed similar time-dependent changes during index finger movement. In both cases, the modulation was maximally present at the onset of the movement and gradually vanished over about 200 ms. Our study provides the first neurophysiological evidence about the relationship between mSI and tactile-motor integration during movement execution.

Abnormal Temporal Coupling of Tactile Perception and Motor Action in Parkinson's Disease.

Evidence shows altered somatosensory temporal discrimination threshold (STDT) in Parkinson's disease in comparison to normal subjects. In healthy subjects, movement execution modulates STDT values through mechanisms of sensory gating. We investigated whether STDT modulation during movement execution in patients with Parkinson's disease differs from that in healthy subjects. In 24 patients with Parkinson's disease and 20 healthy subjects, we tested STDT at baseline and during index finger abductions (at movement onset "0", 100, and 200 ms thereafter). We also recorded kinematic features of index finger abductions. Fifteen out of the 24 patients were also tested ON medication. In healthy subjects, STDT increased significantly at 0, 100, and 200 ms after movement onset, whereas in patients with Parkinson's disease in OFF therapy, it increased significantly at 0 and 100 ms but returned to baseline values at 200 ms. When patients were tested ON therapy, STDT during index finger abductions increased significantly, with a time course similar to that of healthy subjects. Differently from healthy subjects, in patients with Parkinson's disease, the mean velocity of the finger abductions decreased according to the time lapse between movement onset and the delivery of the paired electrical stimuli for testing somatosensory temporal discrimination. In conclusion, patients with Parkinson's disease show abnormalities in the temporal coupling between tactile information and motor outflow. Our study provides first evidence that altered temporal processing of sensory information play a role in the pathophysiology of motor symptoms in Parkinson's disease.