Gina Ferrazzano

Non-motor symptoms in patients with adult-onset focal dystonia: Sensory and psychiatric disturbances *

Dystonia is characterized by the presence of involuntary muscle contractions that cause abnormal movements and posture. Adult onset focal dystonia include cervical dystonia, blepharospasm, arm dystonia and laryngeal dystonia. Besides motor manifestations, patients with focal dystonia frequently also display non-motor signs and symptoms. In this paper, we review the evidence of sensory and psychiatric disturbances in adult patients with focal dystonia. Clinical studies and neurophysiological investigations consistently show that the sensory system is involved in dystonia. Several studies have also demonstrated that neuropsychiatric disorders, particularly depression and anxiety, are more frequent in patients with focal dystonia, whereas data on obsessive compulsive disorders are more contrasting.

Primary somatosensory cortical plasticity and tactile temporal discrimination in focal hand dystonia

OBJECTIVE To investigate whether theta burst stimulation (TBS) applied over primary somatosensory cortex (S1) modulates somatosensory temporal discrimination threshold (STDT) and writing performances in patients with focal hand dystonia (FHD). METHODS Twelve patients with FHD underwent STDT testing and writing tasks before and after intermittent, continuous, or sham TBS (iTBS, cTBS, sham TBS) over S1 contralateral to the affected hand. Twelve healthy subjects underwent iTBS and cTBS over S1 and STDT values were tested on the right hand before and after TBS. RESULTS Baseline STDT values were higher in patients than in healthy subjects on both the affected and unaffected hand. In patients and healthy subjects iTBS decreased, whereas cTBS increased STDT values and did so to a similar extent in both groups. In patients, although STDT values decreased after iTBS, they did not normalize. S1 modulation did not improve the writing performance. CONCLUSIONS In patients, S1 responds normally to protocols inducing homotopic synaptic plasticity. The inhibitory interneuron activity responsible for STDT is altered. SIGNIFICANCE The pathophysiological mechanisms underlying abnormal temporal discrimination differ from those responsible for motor symptoms in FHD.

Somatosensory temporal discrimination tested in patients receiving botulinum toxin injection for cervical dystonia.

We designed this study to find out more about the relationship between the sensory effects of Botulinum toxin type A (BTX) and the clinical benefits of BTX therapy in patients with cervical dystonia (CD). In 24 patients with CD, we tested sensory temporal discrimination (STD) in the affected and two unaffected body regions (neck, hand, and eye) before and 1 month after BTX injection. In 8 out of the 24 patients with CD, STDT values were tested bilaterally in the three body regions before, 1 and 2 months after BTX injection. As expected, STD testing disclosed altered STD threshold values in all three body regions tested (affected and unaffected by dystonic spasms) in patients with CD. STD threshold values remained unchanged at all time points of the follow‐up in all CD patients. The lack of BTX‐induced effects on STD thresholds suggests that STD recruits neural structures uninvolved in muscle spindle afferent activation.

Is increased blinking a form of blepharospasm

Objective: The aim of this study was to investigate whether increased blink rate (BR) is part of the clinical spectrum of primary blepharospasm (BSP). Methods: We enrolled 40 patients (16 patients with an increased BR but without typical orbicularis oculi [OO] spasms, and 24 patients with typical involuntary OO spasms) and 18 healthy subjects. The BR, blink reflex recovery cycle, and somatosensory temporal discrimination threshold (STDT) were tested in patients and controls. Results: Patients who had typical OO spasms had an altered R2 recovery cycle whereas those who had an increased BR alone had a normal blink reflex recovery cycle. STDT values were higher in patients than in healthy subjects and no difference was found in the STDT abnormalities in the 2 groups of patients. Conclusions: Our study shows that, despite the similar STDT abnormalities, the different changes in the R2 recovery cycle in patients with BSP and those with increased BR alone suggest that these disorders arise from different pathologic mechanisms.

Development and validation of a clinical scale for rating the severity of Blepharospasm

Existing scales for rating the severity of blepharospasm (BSP) are limited by a number of potential drawbacks. We therefore developed and validated a novel scale for rating the severity of BSP. The development of the scale started with careful examination of the clinical spectrum of the condition by a panel of experts who selected phenomenological aspects thought to be relevant to disease severity. Thereafter, selected items were first checked for reliability, then reliable items were combined to generate the scale, and clinimetric properties of the scale were evaluated. Finally, the confidence with which the scale could be used by people without high levels of movement disorders skill was assessed. The new scale, based on objective criteria, yielded moderate to almost perfect reliability, acceptable internal consistency, satisfactory scaling assumptions, lack of floor and ceiling effects, partial correlations with a prior severity scale and with a quality of life scale, and good sensitivity to change. Despite a few limitations, the foregoing features make the novel scale more suitable than existing scales to assess the severity of BSP in natural history and pathophysiologic studies as well as in clinical trials.

Somatosensory temporal discrimination in essential tremor and isolated head and voice tremors

The aim of this study was to investigate the somatosensory temporal discrimination threshold in patients with essential tremor (sporadic and familial) and to evaluate whether somatosensory temporal discrimination threshold values differ depending on the body parts involved by tremor. We also investigated the somatosensory temporal discrimination in patients with isolated voice tremor. We enrolled 61 patients with tremor: 48 patients with essential tremor (31 patients with upper limb tremor alone, nine patients with head tremor alone, and eight patients with upper limb plus head tremor; 22 patients with familial vs. 26 sporadic essential tremor), 13 patients with isolated voice tremor, and 45 healthy subjects. Somatosensory temporal discrimination threshold values were normal in patients with familial essential tremor, whereas they were higher in patients with sporadic essential tremor. When we classified patients according to tremor distribution, somatosensory temporal discrimination threshold values were normal in patients with upper limb tremor and abnormal only in patients with isolated head tremor. Temporal discrimination threshold values were also abnormal in patients with isolated voice tremor. Somatosensory temporal discrimination processing is normal in patients with familial as well as in patients with sporadic essential tremor involving the upper limbs. By contrast, somatosensory temporal discrimination is altered in patients with isolated head tremor and voice tremor. This study with somatosensory temporal discrimination suggests that isolated head and voice tremors might possibly be considered as separate clinical entities from essential tremor.

Somatosensory temporal discrimination threshold in Parkinson’s disease parallels disease severity and duration

OBJECTIVE To investigate whether the somatosensory temporal discrimination threshold (STDT) is already altered at the clinical onset of Parkinsons disease (PD) and whether STDT abnormalities correlate with disease progression we tested STDT values in patients with different severity of disease. METHODS We prospectively and consecutively enrolled 63 PD patients: 26 drug-naive PD patients with symptom onset no longer than two years prior to inclusion in the study (early-phase), 37 PD patients with varying degrees of disease severity and 51 age-matched healthy subjects. The STDT was tested on the index finger of both hands, and on both sides of the face. Twelve out of 26 early phase PD patients were re-tested two years after the initial diagnosis. RESULTS PD patients as a whole displayed higher STDT values than healthy subjects. STDT values did not significantly differ between early-phase PD patients and healthy subjects, whereas they were significantly higher in patients with mild/moderate and advanced PD. In early-phase PD patients STDT values at the two years-follow up assessment did not statistically differ from those obtained at baseline. Considering the whole group of PD patients STDT abnormalities significantly correlated with duration and severity of the disease. CONCLUSIONS STDT increases as disease progresses. In early-phase PD patients STDT values are still statistically similar to those of healthy subjects, thus implying that dopaminergic depletion alone may not be sufficient to cause STDT abnormalities. SIGNIFICANCE Our study gives new insight into the sensory abnormalities in PD.

Clinical course of psychiatric disorders in patients with cervical dystonia

We assessed the course of psychiatric disorders in 23 cervical dystonia patients by using the structured clinical interview for DSM-IV and different rating scales. Patients were studied on two occasions 5 years apart. There were no differences in psychiatric disorders and severity of psychiatric symptoms between the two evaluations, whereas the severity of dystonia was milder at the second evaluation. Psychiatric symptoms likely represent a primary disorder in cervical dystonia patients.

Know thyself: Exploring interoceptive sensitivity in Parkinson's disease

BACKGROUND Although Parkinsons disease (PD) is defined by its motor symptoms, it is now well recognised that cognitive, affective and emotion domains are also impaired. The pathophysiology of these disabling non-motor symptoms (NMS) remains unclear; recently the involvement of limbic areas, including the insula, in the neurodegenerative process has been suggested to have a key role. These areas, and the insula in particular, are also been suggested as key regions for interoception; interoceptive sensitivity (IS) is a measure of the accuracy of perception of sensations from inside the body related to the function of internal organs. OBJECTIVES To evaluate IS in PD patients by means of a well-established task: the heartbeat perception task. Moreover, we evaluated possible correlations between IS and psychological, affective and disease-related characteristics as well as fatigue perception in PD patients. METHODS Twenty PD patients and 20 healthy subjects (HS) were included and underwent the heartbeat perception task. An extensive evaluation of motor, non-motor, affective and emotion domains was carried out. RESULTS PD patients showed lower IS than HS (0.58±0.2 vs 0.72±0.1; p=0.04). PD reported higher scores in scales assessing depression (Hamilton depression scale: 8.7±5.8 vs 6.2±7.5; p=0.04); anhedonia (Snaith-Hamilton Pleasure Scale: 26.8±9.7 vs 15.4±2.9; p=<0.001) and apathy (Apathy Evaluation Scale: 35.8±8.6 vs 27.8±6.8; p=0.008). No significant correlations were detected between IS and motor, non-motor, affective and emotion symptoms. CONCLUSIONS PD patients have reduced interoceptive sensitivity. Future studies are encouraged to evaluate the importance of interoception in understanding the pathophysiology of affective/emotional symptoms in PD.

Increased blinking may be a precursor of blepharospasm: a longitudinal study

The objective of this 5‐year longitudinal study was to investigate whether patients with increased blinking develop orbicularis oculi muscle spasms.