Dystonia Diagnosis: Clinical Neurophysiology and Genetics

Abstract

Dystonia diagnosis is based on clinical examination performed by a neurologist with expertise in movement disorders. Clues that indicate the diagnosis of a movement disorder such as dystonia are dystonic movements, dystonic postures, and three additional physical signs (mirror dystonia, overflow dystonia, and geste antagonists/sensory tricks). Despite advances in research, there is no diagnostic test with a high level of accuracy for the dystonia diagnosis. Clinical neurophysiology and genetics might support the clinician in the diagnostic process. Neurophysiology played a role in untangling dystonia pathophysiology, demonstrating characteristic reduction in inhibition of central motor circuits and alterations in the somatosensory system. The neurophysiologic measure with the greatest evidence in identifying patients affected by dystonia is the somatosensory temporal discrimination threshold (STDT). Other parameters need further confirmations and more solid evidence to be considered as support for the dystonia diagnosis. Genetic testing should be guided by characteristics such as age at onset, body distribution, associated features, and coexistence of other movement disorders (parkinsonism, myoclonus, and other hyperkinesia). The aim of the present review is to summarize the state of the art regarding dystonia diagnosis focusing on the role of neurophysiology and genetic testing.

Levodopa-Induced Dyskinesias in Parkinson’s Disease: An Overview on Pathophysiology, Clinical Manifestations, Therapy Management Strategies and Future Directions

“…The last mentioned type occurs only during the OFF phase in the phenomenological form of dystonia [ 46 , 51 , 52 , 53 , 54 ] ( Figure 2 ).…”

Markerless Radio Frequency Indoor Monitoring for Telemedicine: Gait Analysis, Indoor Positioning, Fall Detection, Tremor Analysis, Vital Signs and Sleep Monitoring

“…Blumrosen, Uziel [162] also proposed a technology to assess tremor for the diagnosis of neurological pathologies and its monitoring. A feasibility test was conducted by examining the system performance against an arm model that fluctuated in the range of clinical tremor frequencies (3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The UWB-based acquisition system showed a frequency estimation error of less than 0.1 Hz and provided a set of tremor amplitudes along the tremulous body part.…”

“…Recent trends in the field of personalized medicine highlighted the necessity of empowering medicine with available telemonitoring technologies [ 1 ]. Good example are given by movement disorders like Parkinson’s disease [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ], dystonia [ 9 , 10 , 11 ] or tremor [ 12 , 13 , 14 , 15 ], in which telemonitoring solutions are a promising approach to improve the diagnostic and therapeutic process [ 11 , 16 ]. This approach has been further motivated by the upcoming requests of patients suffering from chronic disorders and their caregivers to receive customized therapies with high accuracy standards and at low costs, since indoor activities appear to be globally more demanding for older people for various reasons.…”

Dystonia and deep brain stimulation: correlation between genetic mutation and clinical outcome

“…On the other hand, according to body distribution DYT-TOR1A, DYT-KMT2B, DYT-THAP1, DYT-HPCA and DYT-PRKRA are the most common causes of generalized dystonia, whereas DYT-TOR1A, DYT-KMT2B and DYT-HPCA typically begin asymmetrically in the lower limbs with secondary generalization (12). DYT-THAP1 may start at the upper half of the body, a ecting the upper limbs and cranio-cervical regions causing speech issues, with subsequent generalization (14). DYT-GNAL and DYT-ANO3 are more likely to cause focal and segmental dystonia, they usually start at the cervical level and can cause a head tremor (12).…”

“…Dystonia-parkinsonism is de ned as the combination of parkinsonism and dystonia and has four monogenic subtypes: DYT/ PARK-GCH1, DYT/PARK-TH, DYT/PARK-TAF1 and DYT/ PARK-ATP1A3 (15). Combined dystonia has a distinct form of heredity, DYT/PARK-GCH1 and DYT/PARK-ATP1A3 exhibit autosomal dominant inheritance, DYT/PARK-TH exhibits autosomal recessive inheritance and DYT/PARK-TAF1 exhibits X-linked transmission (14). Furthermore, myoclonus-dystonia is caused by MYC/DYT-SGCE and MYC/DYT-KCTD17 gene mutation, it typically begins in the rst decade of life and is characterized by generalized myoclonic jerks that occur predomi-nantly in the neck and proximal upper limbs.…”