Optimal location for eliciting the tibial H-reflex and motor response.

INTRODUCTION: Although there are numerous protocols to adjust the amplitude of the Hoffmann reflex (H-reflex) relative to the size of the direct motor response (M-response), the optimal stimulating location has not been described. We sought to determine the optimal positioning of the stimulating cathode when evoking the tibial nerve H-reflex and M-response. METHODS: A small cathode was placed on defined points in the popliteal fossa while an anode was fixed on the patella. The tibial nerve was stimulated electrically, and the response of the soleus muscle was recorded using intramuscular and surface electromyography. RESULTS: We found that more-lateral points along a line drawn across the popliteal fossa were the best locations to obtain only the M-response, whereas stimulating the midpoint was optimal for obtaining only the H-reflex. DISCUSSION: By using specified locations for electrical stimulation to evoke H-reflex and M-response, the functionality of the tibial nerve can be assessed. Muscle Nerve 58:828-833, 2018.

Socio-legal consequences of Tourette Syndrome and its comorbidities: A case study and review of the literature.

Tourette Syndrome is a neurodevelopmental disorder that is associated with the presence of multiple motor and one or more verbal tics. In this case report, we present a 16 years old Tourette syndrome patient who was diagnosed with comorbid Attention Deficit Hyperactivity Disorder. The patient was evaluated for legal responsibility after she made untrue allegations saying that a bus driver had sexually harassed her. We summarize the case and review the current literature to assess the socio-legal aspects of Tourette syndrome.

Assessment of the corticospinal fiber integrity in mirror movement disorder.

Mirror movements are unintended movements occurring on one side of the body that mirror the contralateral voluntary ones. It has been proposed that mirror movements occur due to abnormal decussation of the corticospinal pathways. Using detailed multidisciplinary approach, we aimed to enlighten the detailed mechanism underlying the mirror movements in a case subject who is diagnosed with mirror movements of the hands and we compared the findings with the unaffected control subjects. To evaluate the characteristics of mirror movements, we used several techniques including whole exome sequencing, computed tomography, diffusion tensor imaging and transcranial magnetic stimulation. Computed tomography showed the absence of a spinous process of C5, fusion of the body of C5-C6 vertebrae, hypoplastic dens and platybasia of the posterior cranial fossa. A syrinx cavity was present between levels C3-C4 of the spinal cord. Diffusion tensor imaging of the corticospinal fibers showed disorganization and minimal decussations at the lower medulla oblongata. Transcranial magnetic stimulation showed that motor commands were distributed to the motor neuron pools on the left and right sides of the spinal cord via fast-conducting corticospinal tract fibers. Moreover, a heterozygous missense variation in the deleted in colorectal carcinoma gene has been observed. Developmental absence of the axonal guidance molecules or their receptors may result in abnormalities in the leading of the corticospinal fibers. Clinical evaluations and basic neuroscience techniques, in this case, provide information for this rare disease and contribute to our understanding of the normal physiology of bimanual coordination.