The Experts below are selected from a list of 1644 Experts worldwide ranked by ideXlab platform

Eduardo Tolosa - One of the best experts on this subject based on the ideXlab platform.

  • Clinical Features of Meige's Disease (Idiopathic Orofacial Dystonia)
    2016
    Co-Authors: Eduardo Tolosa
    Abstract:

    \s=b\Seventeen patients with prominent orofacial dystonia of unknown cause (idiopathic orofacial dystonia; Meige's disease) were examined and several clinical features seen that, to my knowledge, had previously not been recognized. These include a family history of dystonia or other extrapyramidal Disorders, a high incidence of depression, and frequent extension of spasms beyond the orofacial muscles. The course of the muscle spasms varies: rapid progression (eg, two months) to maximal disability occurred in some patients, and clear improvement after years of severe disability was observed in others. In addition to the muscle spasms, neurological abnormalities that suggest dysfunction of the basal ganglia were frequently present. The "spasm facial median" of Meige may be a distinct Dystonic Disorder, unrelated to idiopathic torsion dystonia. (Arch Neurol 1981;38:147-151)

Ivan Rektor - One of the best experts on this subject based on the ideXlab platform.

  • Abnormalities of cortical excitability and cortical inhibition in cervical dystonia
    Journal of Neurology, 2003
    Co-Authors: Petr Kaňovský, Martin Bareš, Hana Streitová, Hana Klajblová, Pavel Daniel, Ivan Rektor
    Abstract:

    Cortical excitability and cortico-cortical inhibition were examined in twenty-one patients suffering from idiopathic rotational cervical dystonia. Polymyography of cervical muscles, somatosensory evoked potential recordings, and paired transcranial magnetic stimulation were used to assess the Dystonic Disorder. The results were compared with those obtained in a group of sixteen healthy age-matched volunteers. Statistically significant differences between the patient group and the control group were found when the amplitude values of the mean P22/N30 component measured at F [3, 4] and C[3, 4]' electrode positions were compared. The mean amplitude of P22/N30 in both of these electrode positions contralaterally to the direction of head deviation was significantly higher in the patient group (p ≤ 0.05). The mean side-to-side P22/N30 amplitude ratio was calculated in both groups in the F[3, 4] and C[3, 4]' electrode positions: there was a significant difference between the two groups. The mean ratio (calculated contralaterally/ipsilaterally in the patient group and left/right side in the control group) was significantly higher in the patient group (p ≤ 0.05). There were statistically significant differences between the two groups when the mean values of MEP amplitudes following paired stimuli at short and medium interstimulus intervals (ISI)) were compared. The percentage of amplitude reduction registered at short ISI was significantly lower in the patient group when both 3 ms ISI and 5 ms ISI were considered, and when the hemisphere contralateral to the direction of head deviation was stimulated. There was also a difference (with the short ISI) when the hemisphere ipsilateral to the direction of head deviation was stimulated, but this difference was not significant (p < 0.5). Almost all of the amplitude changes following the paired stimulus at the longer ISI, i. e. 10, 15, and 20 ms were significantly different when the patient group was compared with control group: when the ipsilateral hemisphere was stimulated, the amplitude of conditioned responses was significantly higher following all three paired stimuli (with 10, 15, and 20 ms ISI) at the p ≤ 0.05 significance level; when the contralateral hemisphere was stimulated, they were significantly higher following the 10 and 20 ms ISI paired stimuli (significance level p ≤ 0.05). The interhemispheric difference in the patient group was significant only for the paired stimuli using 3 and 5 ms (short) ISI and 15 and 20 ms (medium) ISI. There was a significantly decreased inhibition at 3 and 5 ms ISI when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). Similarly, there was a significantly increased facilitation at 15 and 20 ms when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). The results indicate that a Disorder of both cortical excitability and intracortical inhibition exists in patients with cervical dystonia, and that this Disorder is lateralized, i. e. it is located within the hemisphere contralateral to the direction of head deviation.

  • Abnormalities of cortical excitability and cortical inhibition in cervical dystonia Evidence from somatosensory evoked potentials and paired transcranial magnetic stimulation recordings.
    Journal of Neurology, 2003
    Co-Authors: Petr Kaňovský, Martin Bareš, Hana Streitová, Hana Klajblová, Pavel Daniel, Ivan Rektor
    Abstract:

    Cortical excitability and cortico-cortical inhibition were examined in twenty-one patients suffering from idiopathic rotational cervical dystonia. Polymyography of cervical muscles, somatosensory evoked potential recordings, and paired transcranial magnetic stimulation were used to assess the Dystonic Disorder. The results were compared with those obtained in a group of sixteen healthy age-matched volunteers. Statistically significant differences between the patient group and the control group were found when the amplitude values of the mean P22/N30 component measured at F [3, 4] and C[3, 4]' electrode positions were compared. The mean amplitude of P22/N30 in both of these electrode positions contralaterally to the direction of head deviation was significantly higher in the patient group (p ≤ 0.05). The mean side-to-side P22/N30 amplitude ratio was calculated in both groups in the F[3, 4] and C[3, 4]' electrode positions: there was a significant difference between the two groups. The mean ratio (calculated contralaterally/ipsilaterally in the patient group and left/right side in the control group) was significantly higher in the patient group (p ≤ 0.05). There were statistically significant differences between the two groups when the mean values of MEP amplitudes following paired stimuli at short and medium interstimulus intervals (ISI)) were compared. The percentage of amplitude reduction registered at short ISI was significantly lower in the patient group when both 3 ms ISI and 5 ms ISI were considered, and when the hemisphere contralateral to the direction of head deviation was stimulated. There was also a difference (with the short ISI) when the hemisphere ipsilateral to the direction of head deviation was stimulated, but this difference was not significant (p < 0.5). Almost all of the amplitude changes following the paired stimulus at the longer ISI, i. e. 10, 15, and 20 ms were significantly different when the patient group was compared with control group: when the ipsilateral hemisphere was stimulated, the amplitude of conditioned responses was significantly higher following all three paired stimuli (with 10, 15, and 20 ms ISI) at the p ≤ 0.05 significance level; when the contralateral hemisphere was stimulated, they were significantly higher following the 10 and 20 ms ISI paired stimuli (significance level p ≤ 0.05). The interhemispheric difference in the patient group was significant only for the paired stimuli using 3 and 5 ms (short) ISI and 15 and 20 ms (medium) ISI. There was a significantly decreased inhibition at 3 and 5 ms ISI when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). Similarly, there was a significantly increased facilitation at 15 and 20 ms when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). The results indicate that a Disorder of both cortical excitability and intracortical inhibition exists in patients with cervical dystonia, and that this Disorder is lateralized, i. e. it is located within the hemisphere contralateral to the direction of head deviation.

Petr Kaňovský - One of the best experts on this subject based on the ideXlab platform.

  • Abnormalities of cortical excitability and cortical inhibition in cervical dystonia
    Journal of Neurology, 2003
    Co-Authors: Petr Kaňovský, Martin Bareš, Hana Streitová, Hana Klajblová, Pavel Daniel, Ivan Rektor
    Abstract:

    Cortical excitability and cortico-cortical inhibition were examined in twenty-one patients suffering from idiopathic rotational cervical dystonia. Polymyography of cervical muscles, somatosensory evoked potential recordings, and paired transcranial magnetic stimulation were used to assess the Dystonic Disorder. The results were compared with those obtained in a group of sixteen healthy age-matched volunteers. Statistically significant differences between the patient group and the control group were found when the amplitude values of the mean P22/N30 component measured at F [3, 4] and C[3, 4]' electrode positions were compared. The mean amplitude of P22/N30 in both of these electrode positions contralaterally to the direction of head deviation was significantly higher in the patient group (p ≤ 0.05). The mean side-to-side P22/N30 amplitude ratio was calculated in both groups in the F[3, 4] and C[3, 4]' electrode positions: there was a significant difference between the two groups. The mean ratio (calculated contralaterally/ipsilaterally in the patient group and left/right side in the control group) was significantly higher in the patient group (p ≤ 0.05). There were statistically significant differences between the two groups when the mean values of MEP amplitudes following paired stimuli at short and medium interstimulus intervals (ISI)) were compared. The percentage of amplitude reduction registered at short ISI was significantly lower in the patient group when both 3 ms ISI and 5 ms ISI were considered, and when the hemisphere contralateral to the direction of head deviation was stimulated. There was also a difference (with the short ISI) when the hemisphere ipsilateral to the direction of head deviation was stimulated, but this difference was not significant (p < 0.5). Almost all of the amplitude changes following the paired stimulus at the longer ISI, i. e. 10, 15, and 20 ms were significantly different when the patient group was compared with control group: when the ipsilateral hemisphere was stimulated, the amplitude of conditioned responses was significantly higher following all three paired stimuli (with 10, 15, and 20 ms ISI) at the p ≤ 0.05 significance level; when the contralateral hemisphere was stimulated, they were significantly higher following the 10 and 20 ms ISI paired stimuli (significance level p ≤ 0.05). The interhemispheric difference in the patient group was significant only for the paired stimuli using 3 and 5 ms (short) ISI and 15 and 20 ms (medium) ISI. There was a significantly decreased inhibition at 3 and 5 ms ISI when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). Similarly, there was a significantly increased facilitation at 15 and 20 ms when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). The results indicate that a Disorder of both cortical excitability and intracortical inhibition exists in patients with cervical dystonia, and that this Disorder is lateralized, i. e. it is located within the hemisphere contralateral to the direction of head deviation.

  • Abnormalities of cortical excitability and cortical inhibition in cervical dystonia Evidence from somatosensory evoked potentials and paired transcranial magnetic stimulation recordings.
    Journal of Neurology, 2003
    Co-Authors: Petr Kaňovský, Martin Bareš, Hana Streitová, Hana Klajblová, Pavel Daniel, Ivan Rektor
    Abstract:

    Cortical excitability and cortico-cortical inhibition were examined in twenty-one patients suffering from idiopathic rotational cervical dystonia. Polymyography of cervical muscles, somatosensory evoked potential recordings, and paired transcranial magnetic stimulation were used to assess the Dystonic Disorder. The results were compared with those obtained in a group of sixteen healthy age-matched volunteers. Statistically significant differences between the patient group and the control group were found when the amplitude values of the mean P22/N30 component measured at F [3, 4] and C[3, 4]' electrode positions were compared. The mean amplitude of P22/N30 in both of these electrode positions contralaterally to the direction of head deviation was significantly higher in the patient group (p ≤ 0.05). The mean side-to-side P22/N30 amplitude ratio was calculated in both groups in the F[3, 4] and C[3, 4]' electrode positions: there was a significant difference between the two groups. The mean ratio (calculated contralaterally/ipsilaterally in the patient group and left/right side in the control group) was significantly higher in the patient group (p ≤ 0.05). There were statistically significant differences between the two groups when the mean values of MEP amplitudes following paired stimuli at short and medium interstimulus intervals (ISI)) were compared. The percentage of amplitude reduction registered at short ISI was significantly lower in the patient group when both 3 ms ISI and 5 ms ISI were considered, and when the hemisphere contralateral to the direction of head deviation was stimulated. There was also a difference (with the short ISI) when the hemisphere ipsilateral to the direction of head deviation was stimulated, but this difference was not significant (p < 0.5). Almost all of the amplitude changes following the paired stimulus at the longer ISI, i. e. 10, 15, and 20 ms were significantly different when the patient group was compared with control group: when the ipsilateral hemisphere was stimulated, the amplitude of conditioned responses was significantly higher following all three paired stimuli (with 10, 15, and 20 ms ISI) at the p ≤ 0.05 significance level; when the contralateral hemisphere was stimulated, they were significantly higher following the 10 and 20 ms ISI paired stimuli (significance level p ≤ 0.05). The interhemispheric difference in the patient group was significant only for the paired stimuli using 3 and 5 ms (short) ISI and 15 and 20 ms (medium) ISI. There was a significantly decreased inhibition at 3 and 5 ms ISI when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). Similarly, there was a significantly increased facilitation at 15 and 20 ms when the hemisphere contralateral to the direction of head deviation was stimulated, as compared with the hemisphere ipsilateral (p ≤ 0.05). The results indicate that a Disorder of both cortical excitability and intracortical inhibition exists in patients with cervical dystonia, and that this Disorder is lateralized, i. e. it is located within the hemisphere contralateral to the direction of head deviation.

Joseph M. Galea - One of the best experts on this subject based on the ideXlab platform.

  • What can kinematic studies tell us about the mechanisms of dystonia
    Progress in Brain Research, 2019
    Co-Authors: Anna Sadnicka, Joseph M. Galea, Mark J. Edwards
    Abstract:

    Abstract Clinical movement Disorders are classified by an algorithm implemented by a practising movement Disorder specialist based on information extracted during the history and clinical examination of a patient. Most simply, dystonia, is a classifier which is reached when a predominant abnormality of posture is noted. In this chapter we summarize studies that have used a variety of techniques to probe beyond the clinical examination and study kinematic features experimentally. We also outline our experimental work in DYT1 dystonia, a group of patients that share a genetically homogenous etiology and can be considered a prototypical Dystonic Disorder. Our results build on previous studies, confirming that motor variability on a trial-by-trial basis is selectively increased and provide evidence that increases in variability are negatively related to forms of motor learning essential for healthy motor control. Potential neural correlates of increased motor variability are discussed and the implications such work has for the rehabilitation of patients with dystonia are also highlighted.

  • High motor variability in DYT1 dystonia is associated with impaired visuomotor adaptation
    Scientific Reports, 2018
    Co-Authors: Anna Sadnicka, Mark J. Edwards, Anna Stevenson, Kailash P. Bhatia, John C. Rothwell, Joseph M. Galea
    Abstract:

    For the healthy motor control system, an essential regulatory role is maintaining the equilibrium between keeping unwanted motor variability in check whilst allowing informative elements of motor variability. Kinematic studies in children with generalised dystonia (due to mixed aetiologies) show that movements are characterised by increased motor variability. In this study, the mechanisms by which high motor variability may influence movement generation in dystonia were investigated. Reaching movements in the symptomatic arm of 10 patients with DYT1 dystonia and 12 age-matched controls were captured using a robotic manipulandum and features of motor variability were extracted. Given that task-relevant variability and sensorimotor adaptation are related in health, markers of variability were then examined for any co-variance with performance indicators during an error-based learning visuomotor adaptation task. First, we confirmed that motor variability on a trial-by-trial basis was selectively increased in the homogenous and prototypical Dystonic Disorder DYT1 dystonia. Second, high baseline variability predicted poor performance in the subsequent visuomotor adaptation task offering insight into the rules which appear to govern Dystonic motor control. The potential mechanisms behind increased motor variability and its corresponding implications for the rehabilitation of patients with DYT1 dystonia are highlighted.

Massachusetts General Hospital - One of the best experts on this subject based on the ideXlab platform.

  • Benign Essential Blepharospasm
    Spencer S. Eccles Health Sciences Library University of Utah, 1996
    Co-Authors: Shirley H. Wray, Professor Of Neurology Harvard Medical School, Unit For Neurovisual Disorders, Massachusetts General Hospital
    Abstract:

    Bilateral Blepharospasm; BlepharospasmPowerPoint Presentation: Blepharospasm Round-Up: http://library.med.utah.edu/NOVEL/Wray/PPT/Blepharospasm_Round_Up_guest_lecture.ppt Shirley H. Wray, M.D., Ph.D., FRCP, Harvard Medical SchoolFrequent blinkingThe patient is a 60 year old estate manager with a history of retinal laser therapy, dry eyes and age related bilateral ptosis. He carries a diagnosis of hilar lymphadenopathy due to sarcoid and has had cancer of the kidney. He presented in 1995 with a 6 month history of frequent blinking and spasms of eye closure that he could not control. He reported driving cautiously because his eyes may shut completely during a spasm and interrupt his vision. He experienced difficulty watching television and reading. These symptoms were aggravated by stress, fatigue, and having to attend social functions which he found embarrassing. He denied any involuntary movements of his lower face. Family History: Negative for blepharospasm, dystonia or neurodegenerative disease including Parkinson's Disease. Past History: Negative for depression and the use of narcoleptic drugs.This patient, with benign essential blepharospasm (BEB), describes very well how disabling this Disorder is and how it disrupted his way of life. Focal dystonia of the eyelids is manifested by frequent blinking and repetitive involuntary sustained contractions of the pre-tarsal portion of the orbicularis oculi muscle. Suppression of frequent blinking is evident when he pays attention to focusing his eyes on a rotating optokinetic drum to follow the black and white lines and by counting out loud up to 30. There are no involuntary movements of the lower face, tongue or neck muscles. The history of dry eyes prior to or at the onset of BEB was considered to be possible precipitating trigger. The video illustrates how to conduct the clinical eyelid examination. 1. Observe the eyes and face when taking the history 2. Assess lid position in different gaze directions 3. Look for blepharoclonus on gentle eye closure 4. Count the blink rate 5. Check for suppression of blepharospasm by visual attention (OKN drum) 6. Look for a positive Glabella tap - An inability to inhibit a blink when the forehead is tapped and 7. Pay attention to the latency and speed of voluntary vertical and horizontal eye movements on command. The differential diagnosis of blepharospasm is straight forward. Conditions to consider are: • Stress Related Excess Blinking/ Voluntary Blepharospasm (see #923-6) • Cranial Dystonia or Meige's Syndrome • Hemifacial Spasm (see #937-1) • Apraxia of Eyelid Opening BEB is a Focal Dystonia confined to the eyelids. Dystonia involving other muscles occurs in approximately 30-40% of patients with bilateral blepharospasm within 6 years as an orderly temporal progression of dystonia in the cranial-cervical area. Oromandibular dystonia is the commonest association with blepharospasm leading to a diagnosis of Cranial Dystonia or Meige's Syndrome.MRI studies are not done routinely in focal eyelid dystonia.The dynamics of normal eyelid blinking depends upon a key eyelid muscle - the levator palpebrae superioris muscle which elevates the lid. This muscle, often referred to as the 7th extraocular muscle, is significantly different from the extraocular muscles in that it contains only singly innervated fibres of the types suitable for fatigue-resistant tonic activity. The motor neurons that activate the levator are located in a single midline central caudal nucleus of the 3rd nerve complex in the midbrain and the levator is innervated by the superior branch of the 3rd nerve. The levator acting alone controls: 1. Tonic lid elevation to keep the eyes open and 2. Voluntary eye closure and eye opening. Two further muscles, innervated by the facial nerve, act on the eyelid: The frontalis muscle which helps to retract the lid in extreme upward gaze, and the orbicularis oculi muscle which controls periodic and reflex blinking and firm eye closure in protective and expressive acts like sneezing. In all kinds of blinks the levator is abruptly inhibited to allow the eyes to close and then it resumes its prior level of activity once the contraction of the palpebral portion of the orbicularis oculi, closing the eyelids momentarily, is over. Conversely, the orbicularis oculi activity precedes and outlasts the levator inhibition in firm eye closure. The brain's control of the eyelids is major. The cerebral cortex (R>L) controls the tonic activity of the levator and voluntary eye opening and eye closure. The dynamics of normal blinks, spontaneous and voluntary, and the frequency of periodic blinks depend on the affective, attentional and cognitive state of the patient. During sleep and when the eyes are gently closed, activity of the levator ceases completely. The extrapyramidal dopaminergic circuit influences the execution of blinks and blink frequency and the basal ganglia play a role in the inhibition of the levator during blinks and eye closure.The fundamental etiology of primary BEB is likely genetic in most cases, even though most cases appear to be sporadic. Secondary cases of BEB arise as a consequence of a lesion of the brain (Basil Ganglia, Thalamus, and Brain Stem) or they are associate with degenerative CNS disease, including: Parkinson's Disease - a dopamine deficiency Progressive Supranuclear Palsy - a tauopathy Multiple System Atrophy Occasionally, secondary BEB occurs as a complication of neuroleptic induced tardive dyskinesia. As with virtually all neurological degenerative Disorders, genetics play a role. "We don't know any of the genes that might be responsible for BEB yet. We do know that all the "late life" focal dystonias are related, likely with the same gene since all these dystonias run in some families. (Defazio et al., 2003). Some families with BEB only have BEB, however, and no other focal dystonia. There is an association with the dopamine D5 receptor in cervical dystonia, and this may be relevant for BEB also. (Brancati et al., 2003) The consequence of the genetic abnormality would be some physiological substrate that would predispose a person to get BEB." (Personal communication Mark Hallett, MD, 2005) At present, the speculation is that the late age of onset of BEB and the company that BEB keeps with progressive degenerative CNS disease suggests that this focal Dystonic Disorder may be secondary to a central disturbance of one or more neurotransmitters and/or synaptic transmission, in genetically predisposed patients.A general recommendation for systemic therapy is to begin an anti-cholinergic drug, slowly building up to a high dose, followed by a trial of baclofen, clonazepam, and then tetrabenazine. When medical therapy fails, the treatment of choice is Botulinum Toxin A (Botox) injections into multiple (10 - 12) sites in the upper and lower eyelids. If this treatment fails, then myectomy, limited or full, is often the next step. This patient declined Botox and he was treated instead by: 1. Partial surgical correction of age related ptosis 2. A trial on Amitriptyline with moderate improvement 3. Sinemet, (carbidopa) 25/100 2 tabs t.i.d. with good results (see post-treatment video 946-4)1. Averbuch-Heller L. Neurology of the eyelids. Current Opinion in Ophthalmology 1997; 8:27-34. http://www.ncbi.nlm.nih.gov/pubmed/10176099 2. Boghen D. The apraxia of lid opening: a review. Neurology 1997; 48:1491-1603. http://www.ncbi.nlm.nih.gov/pubmed/9191752 3. Defazio G, Brancati F, Valente EM, Caputo V, Pizzuti A, Martino D, Abbruzzese G, Livrea P, Berardelli A, Dallapiccola B. Familial blepharospasm is inherited as an autosomal dominant trait and relates to a novel unassigned gene. Mov Disord. 2003 Feb;18(2):207-12. http://www.ncbi.nlm.nih.gov/pubmed/12539217 4. Hallett M. Blepharospasm: recent advances. Neurology. 2002 Nov 12;59(9):1306-12. Review. http://www.ncbi.nlm.nih.gov/pubmed/12434791 5. Hallett M. Dystonia: abnormal movements result from loss of inhibition. Adv Neurol. 2004;94:1-9. Review. http://www.ncbi.nlm.nih.gov/pubmed/14509648 6. Hallett M. Surround inhibition. Suppl Clin Neurophysiol. 2003;56:153-9. Review. http://www.ncbi.nlm.nih.gov/pubmed/14677389 7. Schmidtke K, Buttner-Ennever JA. Nervous Control of Eyelid Function. A review of clinical, experimental and pathological data. Brain 1992; 115:227-247. http://www.ncbi.nlm.nih.gov/pubmed/1559156 8. Wray SH. Blepharospasm Roundup. The 23rd Annual International Benign Essential Blepharospasm Research Foundation Scientific Symposium, Park City Utah. August 2005.curriculum_fellow; KBDblepharospasm; RStreatmento