Dystonia: Five new things

Abnormal Foot Progression Angle Kinematics in Cervical Dystonia Improved After Osteopathic Manipulative Medicine: A Prospective Case Series

Introduction Cervical dystonia (CD), a rare disorder, is the most common form of dystonia, a movement disorder. Impairments in activities of daily living and quality of life may result from chronic pain, perceived stigma, difficulty walking, and/or lack of control over movements. Studies of treatments for difficulty walking in CD have been inconclusive. Osteopathic manipulative medicine (OMM) has been used to improve gait biomechanics in other health conditions. Foot progression angle (FPA) while walking indicates functional gait abnormalities that increase the risk of knee injury and osteoarthritis. Objective The aim of this study is to test if five-weekly treatments using an OMM sequence designed for CD improved abnormal gait biomechanics in individuals with CD by identifying and addressing somatic dysfunctions. Methods In this prospective case series, independently ambulating individuals with CD symptom onset before the age of 40 years, not due to traumatic injury, were evaluated utilizing validated scales for severity (Toronto western spasmodic torticollis rating scale [TWSTRsI]) and symptoms affecting quality of life (Cervical Dystonia Impact Profile [CDIP-58]), physical examination, and FPA before and after five-weekly OMM treatments. Lower body joint range of motion and angles were captured in a clinical gait lab by nine cameras collecting three-dimensional Whole-body position data during three trials of one gait cycle at participant-selected walking speed. The FPA waveforms during the gait cycle were quantified by Vicon Nexus and Polygon applications. Pretreatment and posttreatment results were compared to established healthy gait waveforms and tested by repeated measures ANOVA (α=0.05). Results Pretreatment waveforms in CD had a mean 5.13° of excess FPA during gait cycle phases requiring lower-extremity pronation compared to previously published age-gender-matched healthy waveforms. There was 96% improvement in pronation after five treatments, with a mean 0.21° (p=0.041) of excess FPA. Mean TWSTRs and CDIP-58 scores improved. On physical examination, the rotational direction of C2 vertebrae was contralateral to neck muscle hypertonicity. Vertical sphenobasilar synchondrosis strains were present in those with anterotorticollis. Participants had ipsilateral anterolateral neck muscle and anterolateral abdominal wall muscle hypertonicity. All patients had pelvic somatic dysfunctions with left-side superior relative to right-side and restriction from lower-extremity pronation (i.e., supination dysfunctions). Conclusion The FPA was significantly improved after treatment. This OMM sequence was well tolerated and may be useful for improving gait kinematics in individuals with CD. Randomized, controlled, long-term studies are needed to determine effectiveness.

Contemporary clinical neurophysiology applications in dystonia

The complex phenomenological understanding of dystonia has transcended from the clinics to genetics, imaging and neurophysiology. One way in which electrophysiology will impact into the clinics are cases wherein a dystonic clinical presentation may not be typical or a "forme fruste" of the disorder. Indeed, the physiological imprints of dystonia are present regardless of its clinical manifestation. Underpinnings in the understanding of dystonia span from the peripheral, segmental and suprasegmental levels to the cortex, and various electrophysiological tests have been applied in the course of time to elucidate the origin of dystonia pathophysiology. While loss of inhibition remains to be the key finding in this regard, intricacies and variabilities exist, thus leading to a notion that perhaps dystonia should best be gleaned as network disorder. Interestingly, the complex process has now spanned towards the understanding in terms of networks related to the cerebellar circuitry and the neuroplasticity. What is evolving towards a better and cohesive view will be neurophysiology attributes combined with structural dynamic imaging. Such a sound approach will significantly lead to better therapeutic modalities in the future.

[A case suspected of dystonia with marked cerebellar atrophy with torsion dystonia of the neck and cerebellar ataxia that developed during pharmacologic schizophrenia treatment]

A 46 year-old man with schizophrenia had taken several anti-psychotic drugs since 25 years of age. From ~35 years of age, he noticed occasional neck torsion to the left, and later an ataxic gait; both symptoms gradually worsened. On admission, the patient was taking olanzapine (5 mg/day) and biperiden hydrochloride (1 mg/day) because his schizophrenia was well controlled. His parents were not consanguineous, and there was no family history of neuropsychiatric diseases. On neurological examination, he showed mild cognitive impairment, saccadic eye pursuit with horizontal gaze nystagmus, mild dysarthria, dystonic posture and movement of the neck, incoordination of both hands, and an ataxic gait. Deep tendon reflexes were normal except for the patellar tendon reflex, which was exaggerated bilaterally. Pathological reflexes were negative and there was no sign of rigidity, sensory disturbance or autonomic dysfunction. Ophthalmological examinations detected thinning of the outer macula lutea in both eyes, indicative of macular dystrophy. After admission, all anti-psychotic drugs were ceased, but his dystonia was unchanged. Levodopa and trihexyphenidyl hydrochloride were not effective. General blood, urine and cerebrospinal fluid examinations showed no abnormalities. Brain MRI showed cerebellar atrophy and bilateral symmetrical thalamic lesions without brainstem atrophy or abnormal signals in the basal ganglia. I¹²³-IMP SPECT also revealed a decreased blood flow in the cerebellum. Genetic screening, including whole exome sequencing conducted by the Initiative on Rare and Undiagnosed Disease identified no possible disease-causing variants. The patient's dystonia worsened and choreic movements manifested on his right hand and foot. We suspected dystonia with marked cerebellar atrophy (DYTCA), but could not exclude drug-induced dystonia. Macular dystrophy and bilateral thalamic lesions on brain MRI have not been previously described in DYTCA. Whether these features might be primarily associated with dystonia or cerebellar ataxia now remains to be determined.

[Emotional and personality characteristics of patients with dystonia]

AIM

To examine emotional characteristics, especially personality profile, of patients with dystonia.

MATERIAL AND METHODS

Three hundred patients with dystonia were enrolled in the study. Control groups consisted of 50 healthy individuals and 62 patients with hemifacial spasm (GFS). HADS, Beck depression inventory and Spielberger-Khanin anxiety scale were used. The 16 Personality Factors Questionnaire (16PF) was used to study personality profile.

RESULTS AND CONCLUSION

Higher levels of anxiety and depression in patients with dystonia compared to the control groups were identified. The level of anxiety and depression was not correlated with disease severity. Personality profile study confirmed the high level of anxiety in patients with dystonia and additionally showed increased emotional instability and poor emotional control. Intellectual personality characteristics of patients with dystonia had no differences compared to the control groups. An analysis of socio-psychological characteristics of personality in patients with dystonia and GFS showed restricted interpersonal and social communications since the motor defect noticeable to others leads to severe social exclusion and the desire for self-isolation.

Does the Somatosensory Temporal Discrimination Threshold Change over Time in Focal Dystonia?

Background

The somatosensory temporal discrimination threshold (STDT) is defined as the shortest interval at which an individual recognizes two stimuli as asynchronous. Some evidence suggests that STDT depends on cortical inhibitory interneurons in the basal ganglia and in primary somatosensory cortex. Several studies have reported that the STDT in patients with dystonia is abnormal. No longitudinal studies have yet investigated whether STDT values in different forms of focal dystonia change during the course of the disease.

Methods

We designed a follow-up study on 25 patients with dystonia (15 with blepharospasm and 10 with cervical dystonia) who were tested twice: upon enrolment and 8 years later. STDT values from dystonic patients at the baseline were also compared with those from a group of 30 age-matched healthy subjects.

Results

Our findings show that the abnormally high STDT values observed in patients with focal dystonia remained unchanged at the 8-year follow-up assessment whereas disease severity worsened.

Conclusions

Our observation that STDT abnormalities in dystonia remain unmodified during the course of the disease suggests that the altered activity of inhibitory interneurons—either at cortical or at subcortical level—responsible for the increased STDT does not deteriorate as the disease progresses.

The Burke-Fahn-Marsden Dystonia Rating Scale is Age-Dependent in Healthy Children

Background

The Burke-Fahn-Marsden Dystonia Rating Scale is a universally applied instrument for the quantitative assessment of dystonia in both children and adults. However, immature movements by healthy young children may also show "dystonic characteristics" as a consequence of physiologically incomplete brain maturation. This could implicate that Burke-Fahn-Marsden scale scores are confounded by pediatric age.

Objective

In healthy young children, we aimed to determine whether physiologically immature movements and postures can induce an age-related effect on Burke-Fahn-Marsden movement and disability scale scores.

Methods

Nine assessors specializied in movement disorders (3 adult neurologists, 3 pediatric neurologists, and 3 MD/PhD students) independently scored the Burke-Fahn-Marsden movement scale in 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). Independent of that, parents scored their children's functional motor development according to the Burke-Fahn-Marsden disability scale in another 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). By regression analysis, we determined the association between Burke-Fahn-Marsden movement and disability scales outcomes and pediatric age.

Results

In healthy children, assessment of physiologically immature motor performances by the Burke-Fahn-Marsden movement and disability scales showed an association between the outcomes of both scales and age (until 16 years and 12 years of age, β = -0.72 and β = -0.60, for Burke-Fahn-Marsden movement and disability scale, respectively [both P < 0.001]).

Conclusions

The Burke-Fahn-Marsden movement and disability scales are influenced by the age of the child. For accurate interpretation of longitudinal Burke-Fahn-Marsden Dystonia Rating Scale scores in young dystonic children, consideration of pediatric age-relatedness appears advisory.

Recent developments in dystonia

PURPOSE OF REVIEW

The dystonias are a family of related disorders with many different clinical manifestations and causes. This review summarizes recent developments regarding these disorders, focusing mainly on advances with direct clinical relevance from the past 2 years.

RECENT FINDINGS

The dystonias are generally defined by their clinical characteristics, rather than by their underlying genetic or neuropathological defects. The many varied clinical manifestations and causes contribute to the fact that they are one of the most poorly recognized of all movement disorders. A series of recent publications has addressed these issues, offering a revised definition and more logical means for classifying the many subtypes. Our understanding of the genetic and neurobiological mechanisms responsible for different types of dystonias also has grown rapidly, creating new opportunities and challenges for diagnosis, and identifying increasing numbers of rare subtypes for which specific treatments are available.

SUMMARY

Recent advances in describing the clinical phenotypes and determining associated causes have pointed to the need for new strategies for diagnosis, classification, and treatment of the dystonias.

A De Novo Mutation in MTND6 Causes Generalized Dystonia in 2 Unrelated Children

Dystonia is often associated with the symmetrical basal ganglia lesions of Leigh syndrome. However, it has also been associated with mitochondrial ND mutations, with or without Leber hereditary optic neuropathy. The m.14459G>A mutation in ND6 causes dystonia with or without familial Leber hereditary optic neuropathy. We report heteroplasmic 14459G>A mutations in 2 unrelated children with nonmaternally inherited generalized dystonia and showing bilateral magnetic resonance imaging lesions in nucleus pallidus and putamen. Both children have reached their teenage years, and they are intellectually active, despite their motor problems.