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Brain : a Journal of Neurology Jun 2022CANVAS caused by RFC1 biallelic expansions is a major cause of inherited sensory neuronopathy. Detection of RFC1 expansion is challenging and CANVAS can be associated...
CANVAS caused by RFC1 biallelic expansions is a major cause of inherited sensory neuronopathy. Detection of RFC1 expansion is challenging and CANVAS can be associated with atypical features. We clinically and genetically characterized 50 patients, selected based on the presence of sensory neuronopathy confirmed by EMG. We screened RFC1 expansion by PCR, repeat-primed PCR, and Southern blotting of long-range PCR products, a newly developed method. Neuropathological characterization was performed on the brain and spinal cord of one patient. Most patients (88%) carried a biallelic (AAGGG)n expansion in RFC1. In addition to the core CANVAS phenotype (sensory neuronopathy, cerebellar syndrome and vestibular impairment), we observed chronic cough (97%), oculomotor signs (85%), motor neuron involvement (55%), dysautonomia (50%), and parkinsonism (10%). Motor neuron involvement was found for 24 of 38 patients (63.1%). First motor neuron signs, such as brisk reflexes, extensor plantar responses, and/or spasticity, were present in 29% of patients, second motor neuron signs, such as fasciculations, wasting, weakness, or a neurogenic pattern on EMG in 18%, and both in 16%. Mixed motor and sensory neuronopathy was observed in 19% of patients. Among six non-RFC1 patients, one carried a heterozygous AAGGG expansion and a pathogenic variant in GRM1. Neuropathological examination of one RFC1 patient with an enriched phenotype, including parkinsonism, dysautonomia, and cognitive decline, showed posterior column and lumbar posterior root atrophy. Degeneration of the vestibulospinal and spinocerebellar tracts was mild. We observed marked astrocytic gliosis and axonal swelling of the synapse between first and second motor neurons in the anterior horn at the lumbar level. The cerebellum showed mild depletion of Purkinje cells, with empty baskets, torpedoes, and astrogliosis characterized by a disorganization of the Bergmann's radial glia. We found neuronal loss in the vagal nucleus. The pars compacta of the substantia nigra was depleted, with widespread Lewy bodies in the locus coeruleus, substantia nigra, hippocampus, entorhinal cortex, and amygdala. We propose new guidelines for the screening of RFC1 expansion, considering different expansion motifs. Here, we developed a new method to more easily detect pathogenic RFC1 expansions. We report frequent motor neuron involvement and different neuronopathy subtypes. Parkinsonism was more prevalent in this cohort than in the general population, 10% versus the expected 1% (P < 0.001). We describe, for the first time, the spinal cord pathology in CANVAS, showing the alteration of posterior columns and roots, astrocytic gliosis and axonal swelling, suggesting motor neuron synaptic dysfunction.
Topics: Cerebellar Ataxia; Gliosis; Humans; Motor Neurons; Primary Dysautonomias; Reflex, Abnormal
PubMed: 34927205
DOI: 10.1093/brain/awab449 -
NPJ Primary Care Respiratory Medicine Mar 2016
Topics: Chronic Disease; Cough; Disease Management; Humans; Reflex, Abnormal; Syndrome
PubMed: 26937873
DOI: 10.1038/npjpcrm.2016.12 -
Neurologia Medico-chirurgica Nov 2020The hanger reflex is a phenomenon characterized by the involuntary rotation of the head when a wire hanger is worn around the head such that a force is applied to the... (Review)
Review
The hanger reflex is a phenomenon characterized by the involuntary rotation of the head when a wire hanger is worn around the head such that a force is applied to the frontal temporal area by the longer side of the hanger. The application of a shearing force on the skin is thought to be the cause of this phenomenon. Attempts have been made to treat cervical dystonia using equipment designed to induce the hanger reflex. This reflex may have implications in the treatment of headaches, cervical pain, and adhesive capsulitis. The hanger reflex is seen not only in the head region but is also in other parts of the body. Thus, it could be used in the treatment of systemic dystonias. The hanger reflex may help develop inexpensive and non-invasive treatment for dystonia or other neurological diseases and is expected to be the focus of research in the future.
Topics: Humans; Nervous System Diseases; Reflex, Abnormal; Torticollis
PubMed: 33071275
DOI: 10.2176/nmc.ra.2020-0156 -
Indian Pediatrics Mar 2004
Topics: Child, Preschool; Corneal Opacity; Female; Humans; Pupil Disorders; Reflex, Abnormal; Reflex, Pupillary; Retinal Neoplasms; Retinoblastoma
PubMed: 15064521
DOI: No ID Found -
Journal of Diabetes Research 2021Blink reflex provides an objective assessment of the cranial and central nervous systems. However, the relationships between body mass index, dizziness, and BR have not...
Blink reflex provides an objective assessment of the cranial and central nervous systems. However, the relationships between body mass index, dizziness, and BR have not been explored in patients with type 2 diabetes mellitus (T2DM). Moreover, R2 duration, one of the parameters of the blink reflex, has not been studied to date. In the present study, we aimed to investigate the characteristics and influencing factors of blink reflex in patients with T2DM. We included 45 healthy subjects and 105 hospitalized patients with T2DM. The relationships between these parameters and sex, age, body mass index, duration of T2DM, hemoglobin A1c, distal symmetrical polyneuropathy (DSPN), and dizziness symptoms were analyzed. The results showed that blink reflex latencies (including R1, ipsilateral R2, and contralateral R2 latency) were negatively associated with body mass index but were positively correlated with the duration of T2DM. There were no correlations between blink reflex parameters and sex, age, and hemoglobin A1c. Patients with DSPN had longer blink reflex latencies and shorter R2 durations than those without DSPN. Patients with dizziness had longer latencies (including R1, ipsilateral R2, and contralateral R2 latencies) and shorter R2 durations (including ipsilateral R2 and contralateral R2 durations) than those without dizziness. R2 duration was also a predictive factor for blink reflex abnormality. R2 latency was the most sensitive factor and the optimal predictor of dizziness. These results demonstrate that patients with T2DM with low body mass index, longer duration of T2DM, DSPN, and dizziness-related symptoms had more abnormal blink reflex parameters, indicating more serious injuries to the cranial nerves or the central nervous system.
Topics: Adult; Aged; Blinking; Body Mass Index; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Dizziness; Female; Humans; Male; Middle Aged; Polyneuropathies; Reaction Time; Reflex, Abnormal
PubMed: 33791387
DOI: 10.1155/2021/2473193 -
British Medical Journal Feb 1972
Topics: Cataract; Cerebellar Ataxia; Cholesterol; Female; Humans; Intellectual Disability; Middle Aged; Reflex, Abnormal; Tendons; Xanthomatosis
PubMed: 5008664
DOI: 10.1136/bmj.1.5796.353 -
Journal of Neurophysiology Mar 2018Many studies highlight the remarkable plasticity demonstrated by spinal circuits following an incomplete spinal cord injury (SCI). Such plasticity can contribute to... (Review)
Review
Many studies highlight the remarkable plasticity demonstrated by spinal circuits following an incomplete spinal cord injury (SCI). Such plasticity can contribute to improvements in volitional motor recovery, such as walking function, although similar mechanisms underlying this recovery may also contribute to the manifestation of exaggerated responses to afferent input, or spastic behaviors. Rehabilitation interventions directed toward augmenting spinal excitability have shown some initial success in improving locomotor function. However, the potential effects of these strategies on involuntary motor behaviors may be of concern. In this article, we provide a brief review of the mechanisms underlying recovery of volitional function and exaggerated reflexes, and the potential overlap between these changes. We then highlight findings from studies that explore changes in spinal excitability during volitional movement in controlled conditions, as well as altered kinematic and behavioral performance during functional tasks. The initial focus will be directed toward recovery of reflex and volitional behaviors following incomplete SCI, followed by recent work elucidating neurophysiological mechanisms underlying patterns of static and dynamic muscle activation following chronic incomplete SCI during primarily single-joint movements. We will then transition to studies of locomotor function and the role of altered spinal integration following incomplete SCI, including enhanced excitability of specific spinal circuits with physical and pharmacological interventions that can modulate locomotor output. The effects of previous and newly developed strategies will need to focus on changes in both volitional function and involuntary spastic reflexes for the successful translation of effective therapies to the clinical setting.
Topics: Animals; Brain-Derived Neurotrophic Factor; Humans; Locomotion; Neuronal Plasticity; Physical Therapy Modalities; Psychomotor Performance; Recovery of Function; Reflex, Abnormal; Selective Serotonin Reuptake Inhibitors; Spinal Cord; Spinal Cord Injuries; Volition
PubMed: 29093168
DOI: 10.1152/jn.00051.2017 -
Epilepsia Dec 2012Startle syndromes are paroxysmal and show stimulus sensitivity, placing them in the differential diagnosis of epileptic seizures. Startle syndromes form a heterogeneous... (Review)
Review
Startle syndromes are paroxysmal and show stimulus sensitivity, placing them in the differential diagnosis of epileptic seizures. Startle syndromes form a heterogeneous group of disorders with three categories: hyperekplexia (HPX), stimulus-induced disorders, and neuropsychiatric syndromes. HPX is characterized by an exaggerated motor startle reflex combined with stiffness and is caused by mutations in different parts of the inhibitory glycine receptor, leading to brainstem pathology. The preserved consciousness distinguishes it from epileptic seizures. Clonazepam is the first-choice therapy. The stimulus-induced disorders cover a broad range of epileptic and nonepileptic disorders, and distinguishing the two can be difficult. Additional information from electroencephalography (EEG) and video registration can help. Many stimulus-induced disorders now have an identified gene defect. Antiepileptic drugs, including benzodiazepines, are frequently mentioned as the best treatment option. Neuropsychiatric syndromes are on the borderland of neurology and psychiatry, and their etiology is poorly understood. These syndromes include startle-induced tics, culture-specific disorders such as Latah, and functional startle syndromes. The electromyography (EMG) startle reflex in these syndromes is characterized by variable recruitment patterns and the presence of a second "orienting" response. Treatment options are limited, but urgently required. In the clinical setting, the patient's history and a (home) video recording together with genetic and electrophysiologic testing help to classify these challenging disorders.
Topics: Humans; Movement Disorders; Reflex, Abnormal; Reflex, Startle; Syndrome
PubMed: 23153204
DOI: 10.1111/j.1528-1167.2012.03709.x -
Restorative Neurology and Neuroscience 2010To review the extent and mechanism of the recovery of vestibular function after sudden, isolated, spontaneous, unilateral loss of most or all peripheral vestibular... (Review)
Review
PURPOSE
To review the extent and mechanism of the recovery of vestibular function after sudden, isolated, spontaneous, unilateral loss of most or all peripheral vestibular function - usually called acute vestibular neuritis.
METHODS
Critical review of published literature and personal experience.
RESULTS
The symptoms and signs of acute vestibular neuritis are vertigo, vomiting, nystagmus with ipsiversive slow-phases, ipsiversive lateropulsion and ocular tilt reaction (the static symptoms) and impairment of vestibulo-ocular reflexes from the ipsilesional semicircular canals on impulsive testing (the dynamic symptoms). Peripheral vestibular function might not improve and while static symptoms invariably resolve, albeit often not totally, dynamic symptoms only improve slightly if at all.
CONCLUSIONS
The persistent loss of balance that some patients experience after acute vestibular neuritis can be due to inadequate central compensation or to incomplete peripheral recovery and vestibular rehabilitation has a role in the treatment of both.
Topics: Adaptation, Physiological; Animals; Gait Disorders, Neurologic; Humans; Nystagmus, Pathologic; Recovery of Function; Reflex, Abnormal; Reflex, Vestibulo-Ocular; Semicircular Canals; Vertigo; Vestibular Neuronitis; Vomiting
PubMed: 20086281
DOI: 10.3233/RNN-2010-0533 -
Experimental Neurology May 2012Whether dramatic or modest, recovery of neurological function after spinal cord injury (SCI) is greatly due to neuroplasticity--the process by which the nervous system... (Review)
Review
Whether dramatic or modest, recovery of neurological function after spinal cord injury (SCI) is greatly due to neuroplasticity--the process by which the nervous system responds to injury by establishing new synaptic connections or by altering the strength of existing synapses. However, the same neuroplasticity that allows locomotor function to recover also produces negative consequences such as pain and dysfunction of organs controlled by the autonomic nervous system. In this review we focus specifically on structural neuroplasticity (the growth of new synaptic connections) after SCI and on the consequent development of pain and autonomic dysreflexia, a condition of episodic hypertension. Neuroplasticity after SCI is stimulated by the deafferentation of spinal neurons below the lesion and by the expression of growth-promoting neurotrophins such as nerve growth factor (NGF). A broad range of therapeutic strategies that affect neuroplasticity is being developed for the treatment of SCI. At one end of the spectrum are therapeutic strategies that directly or indirectly increase NGF in the injured spinal cord, and have the most robust effects on neuroplasticity. At the other end of the spectrum are neuroprotective strategies focused on supporting and rescuing uninjured, or partially injured, axons; these might limit the deafferentation stimulus for neuroplasticity. In the middle of this spectrum are strategies that block axon growth inhibitors without necessarily providing a growth stimulus. The literature supports the view that the negative consequences of neuroplasticity develop more commonly with therapies that directly stimulate nerve growth than they develop in the untreated injured cord. Compared to these conditions, neuroplasticity with negative outcomes is less prevalent after treatments that that neutralize axon growth inhibitors, and least apparent after strategies that promote neuroprotection.
Topics: Animals; Autonomic Dysreflexia; Axons; Neuronal Plasticity; Pain; Reflex, Abnormal; Spinal Cord Injuries
PubMed: 22116043
DOI: 10.1016/j.expneurol.2011.11.004