Reversal of Temporal Discrimination in Cervical Dystonia after Low-Frequency Sensory Stimulation

BACKGROUND

Somatosensory temporal discrimination is abnormal in dystonia and reflects reduced somatosensory inhibition. In healthy individuals, both the latter are enhanced by high-frequency repetitive somatosensory stimulation, whereas opposite effects are observed in patients with cervical dystonia.

OBJECTIVES

We tested whether low-frequency repetitive sensory stimulation, which in healthy individuals worsens discrimination, might have the opposite effect in patients with cervical dystonia at the physiological level and, in turn, improve their perceptual performance.

METHODS

Somatosensory temporal discrimination and several electrophysiological measures of sensorimotor inhibition were collected before and after 45 minutes of low-frequency repetitive sensory stimulation.

RESULTS

As predicted, and opposite to what happened in controls, low-frequency repetitive sensory stimulation in patients enhanced sensorimotor inhibition and normalized somatosensory temporal discrimination.

CONCLUSIONS

Patients with cervical dystonia have an abnormal response to repetitive sensory stimulation, which we hypothesize is attributed to abnormally sensitive homeostatic mechanisms of inhibitory circuitry in both sensory and motor systems. © 2020 International Parkinson and Movement Disorder Society.

Characterizing Brain Network Topology in Cervical Dystonia Patients and Unaffected Relatives via Graph Theory

Cervical Dystonia (CD) is a neurological movement disorder characterized by intermittent muscle contractions in the head and neck. The pathophysiology and neural networks underpinning this condition are incompletely understood. There is increasing evidence that isolated focal dystonias are due to network-wide functional alterations. An abnormal temporal discrimination threshold (TDT) is believed to be a mediational endophenotype due to its prevalence in unaffected first-degree relatives as well as patients. However the neural correlates linking abnormal TDT and CD remain poorly understood. Probing changes in large-scale network topology via graph theory with resting state fMRI data from relatives and patients may provide further insight into the pathophysiology of CD. In this study, resting state fMRI data were acquired and analyzed from 16 CD patients with abnormal TDT, 32 unaffected first degree relatives (16 with normal TDT and 16 with abnormal TDT) and 16 healthy controls. Graph theory metrics demonstrating network topology were extracted. The results indicate large-scale functional reorganization of networks in relatives (with abnormal TDT) along with a manifestation of topological aberrations similar to patients.

[A COMPARATIVE STUDY ON TREATMENT OF SCAR CONTRACTURE ON FACE, NECK, AND JOINTS WITH PRE-EXPANDED FLAPS AND SKIN GRAFTS]

OBJECTIVE

To study the treatment results of the pre-expanded flaps for scar contracture on face, neck, and joints by comparing with the skin grafts.

METHODS

A total of 240 cases of scar contracture between July 2004 and June 2014 were included in the study by random sampling; skin grafts were used in 120 cases (skin graft group), and pre-expanded flaps in 120 cases (pre-expanded flap group). There was no significant difference in age, sex, injury sites, and disease duration between 2 groups (P>0.05). Re-operation rate and A&F 0-6 quantization score were used to evaluate the treatment results.

RESULTS

The patients were followed up 12 to 75 months (mean, 23.47 months) in the skin graft group, and 12 to 61 months (mean, 19.62 months) in the pre-expanded flap group. The re-operation rate of the skin graft group was 72.5% (87/120), and was significantly higher than that of the pre-expanded flap group (19.2%, 23/120) (P=0.000). The re-operation rate of the neck contracture in teenagers was the highest. It was 93.9% in the skin graft group and 35.0% in the pre-expanded flap group. In the patients who did not undergo re-operations, A&F 0-6 quantization score of the skin graft group was 2.85±1.12, and was significantly lower than that of the pre-expanded flap group (5.22±0.74) (t=13.830, P=0.000).

CONCLUSION

Pre-expanded flap for scar contracture on face, neck, and joints has lower re-operation rate and better aesthetic and functional restoration than skin graft. It should be regarded as the preferred method for teenagers.

Neck muscle fatigue affects postural control in man

We hypothesised that, since anomalous neck proprioceptive input can produce perturbing effects on posture, neck muscle fatigue could alter body balance control through a mechanism connected to fatigue-induced afferent inflow. Eighteen normal subjects underwent fatiguing contractions of head extensor muscles. Sway during quiet stance was recorded by a dynamometric platform, both prior to and after fatigue and recovery, with eyes open and eyes closed. After each trial, subjects were asked to rate their postural control. Fatigue was induced by having subjects stand upright and exert a force corresponding to about 35% of maximal voluntary effort against a device exerting a head-flexor torque. The first fatiguing period lasted 5 min (F1). After a 5-min recovery period (R1), a second period of fatiguing contraction (F2) and a second period of recovery (R2) followed. Surface EMG activity from dorsal neck muscles was recorded during the contractions and quiet stance trials. EMG median frequency progressively decreased and EMG amplitude progressively increased during fatiguing contractions, demonstrating that muscle fatigue occurred. After F1, subjects swayed to a larger extent compared with control conditions, recovering after R1. Similar findings were obtained after F2 and after R2. Although such behaviour was detectable under both visual conditions, the effects of fatigue reached significance only without vision. Subjective scores of postural control diminished when sway increased, but diminished more, for equal body sway, after fatigue and recovery. Contractions of the same duration, but not inducing EMG signs of fatigue, had much less influence on body sway or subjective scoring. We argue that neck muscle fatigue affects mechanisms of postural control by producing abnormal sensory input to the CNS and a lasting sense of instability. Vision is able to overcome the disturbing effects connected with neck muscle fatigue.

Unilateral split foot, torticollis, congenital heart defect and hydrocephaly: a new syndrome?

We report a patient showing unilateral split foot together with unusual malformations.

Nuchal aggressive fibromatosis in childhood: two instructive case reports

Aggressive fibromatosis is a rare, benign tumour with a capacity for infiltration of surrounding structures and a propensity for local recurrence. The cornerstone of therapy is surgery, with various other treatment modalities having ill-defined roles. Assessment of the efficacy of these interventions is difficult. The natural history of the condition is variable and different treatment modalities are often used concurrently. Childhood cases pose particular management problems because of their tendency to occur in the head and neck region and the potential for treatment-related morbidity. Two children presented after surgery with recurrent disease threatening the airway. One remitted spontaneously and remains disease free at 20 years. The other achieved a complete remission with radiotherapy and toremifene. The role of non-surgical treatment, particularly radiotherapy, is reviewed.

A novel mutation of the GTP-cyclohydrolase I gene in a patient with hereditary progressive dystonia/dopa-responsive dystonia

We report a 37-year-old Japanese woman with hereditary progressive dystonia with marked diurnal fluctuation and dopa-responsive dystonia. She developed dystonia in the lower limbs at the age of 11 years, followed by spasmodic torticollis and resting tremor of the feet, which responded remarkably to low doses of levodopa (100 mg/day). Concentrations of biopterin and neopterin in CSF were decreased. Polymerase chain reaction analysis of the guanosine 5'-triphosphate cyclohydrolase I gene revealed a novel mutation (Thr186-->Lys).

Congenital muscular dystrophy with severe retrocollis and mental retardation: a report of two siblings

Two siblings with a congenital muscular dystrophy and severe mental retardation which was not due to dystrophin, merosin, or adhalin deficiency are described. These cases overlap with congenital muscular dystrophy of the Fukuyama-type but are less severe. Atypical features include limited facial involvement, retained ambulation, and severe retrocollis.