Regulatory Considerations for the Clinical and Research Use of Transcranial Direct Current Stimulation (tDCS): review and recommendations from an expert panel

The field of transcranial electrical stimulation (tES) has experienced significant growth in the past 15 years. One of the tES techniques leading this increased interest is transcranial direct current stimulation (tDCS). Significant research efforts have been devoted to determining the clinical potential of tDCS in humans. Despite the promising results obtained with tDCS in basic and clinical neuroscience, further progress has been impeded by a lack of clarity on international regulatory pathways. We therefore convened a group of research and clinician experts on tDCS to review the research and clinical use of tDCS. In this report, we review the regulatory status of tDCS, and we summarize the results according to research, off-label and compassionate use of tDCS in the following countries: Australia, Brazil, France, Germany, India, Iran, Italy, Portugal, South Korea, Taiwan and United States. Research use, off label treatment and compassionate use of tDCS are employed in most of the countries reviewed in this study. It is critical that a global or local effort is organized to pursue definite evidence to either approve and regulate or restrict the use of tDCS in clinical practice on the basis of adequate randomized controlled treatment trials.

The optimal measurement of across elbow segment in ulnar motor conduction study

There is room for considerable error in the measurement of across-elbow conduction velocity due to the different possible positions of the elbow and the difficulty in accurately measuring distance. A standardized method should be used for clinical measurement. Many advocate a fully flexed elbow position with the arm abducted at 90 degrees. When the elbow is fully flexed, skin measurement across the bent elbow is difficult with respect to defining the path, which most accurately follows the nerve. However, studies on measurement technique for across-elbow segment have not been performed to date. We have proposed a standardized technique for the measurement of conduction velocity through the elbow segment. We assumed "ideal" across-elbow segmental conduction velocity is the mean of the forearm and arm segmental conduction velocities, and established an optimal deflection point at the elbow, which best reflects the ideal conduction velocity. The optimal deflection point was located medially two thirds distance between the epicondyle and the olecranon in an arm abducted 90 degrees, fully flexed elbow position. Our data suggests that an across-elbow segment velocity lower than 57.8 m/sec, or a difference of more than 7.7 m/sec between the across-elbow and forearm segments is to be considered abnormal. The lower limit values expressed as mean-2 S.D. for absolute across-elbow segmental conduction velocity and relative velocity difference between the across-elbow segment and forearm segments at other possible deflection points of the elbow were also calculated.

Quantifying swallowing function after stroke: A functional dysphagia scale based on videofluoroscopic studies

OBJECTIVE

To develop a sensitive, specific scale for quantifying functional dysphagia in stroke patients, using results obtained from videofluoroscopic swallowing studies.

DESIGN

Data collected from a serial oral and pharyngeal videofluoroscopic swallowing study.

SETTING

A dysphagia clinic in a department of rehabilitation medicine at a tertiary care university hospital.

PARTICIPANTS

One hundred three consecutively admitted stroke patients.

INTERVENTIONS

Videoflurorscopy to measure a scale of 11 variables: lip closure score, bolus formation, residue in oral cavity, oral transit time, triggering of pharyngeal swallow, laryngeal elevation and epiglottic closure, nasal penetration, residue in valleculae, coating of pharyngeal wall after swallow, and pharyngeal transit time.

MAIN OUTCOME MEASURES

Polychotomous linear logistic regression analysis of videofluoroscopic and aspiration results. Scale sensitivity and specificity, and the correlation between the total score of the scale and aspiration grade were analyzed.

RESULTS

The scale's sensitivity and specificity for detecting supraglottic penetration and subglottic aspiration were 81%, 70.7%, and 78.1%, 77.9%, respectively. A significant positive correlation was found between the scale's total score and the severity of aspiration (Spearman's r =.58943, p =.00001).

CONCLUSION

This functional dysphagia scale, which was based on a videofluoroscopic swallowing study in stroke patients, is a sensitive and specific method for quantifying the severity of dysphagia.

Effect of facilitation on side-to-side H reflex amplitude ratio

Although voluntary facilitation is sometimes necessary to evoke the H reflex, relevant data is lacking on side-to-side amplitude ratios in facilitated condition. To determine the normal limits of H reflex amplitude ratio in facilitation and to assess it's clinical applicability, we performed FCR H reflex study in fifty asymptomatic subjects. The lower limit of the amplitude ratio that encompasses 97.5% of subjects in facilitation was 0.48. These data suggest H reflex amplitude ratio measured in facilitation without averaging is useful for the diagnosis of unilateral radiculopathy.

Multiple peripheral nerve compressions related to malignantly transformed hereditary multiple exostoses

Autosomal dominantly transmitted hereditary multiple exostoses is an uncommon disorder consisting of multiple projections of bone capped by cartilage. The lesions are most numerous in the metaphyses of long bones but may appear on flat bones. Sarcomatous transformation occurs in 1-25% of patients. We report a 33-year-old man with sciatica, previously diagnosed as hereditary multiple exostoses, presenting with multiple peripheral nerve compressions. Electrodiagnostic studies showed profound axon-loss multiple neuropathies involving the sciatic, superior gluteal, and inferior gluteal nerves. Magnetic resonance imaging of the left pelvis showed a large mass in the sacral area that was suggestive of a chondrosarcoma. An open intralesional excision biopsy confirmed chondrosarcoma transformed from chondromatosis. Excision of the lesion was effective in eliminating the impingement of nerves and retarding progressive osseous growth. We suggest that malignant transformation be suspected in cases with focal compression neuropathy of patients known to have multiple exostoses. Osteochondroma as a possible cause for compression neuropathy is discussed.

Quantification of the path of center of pressure (COP) using an F-scan in-shoe transducer

By tracking the path of the center of pressure (COP) during the stance phase, the balance and pattern of progression can be determined. The path of COP is frequently used in clinical practice, although it is not quantified. In this study, an F-scan pressure sensitive insole system was used to quantify the path of COP. The COP of initial contact and the average during the stance phase corresponded to the center of the heel and to the center of the total plantar surface, respectively. The COP displacement corresponded to 83% of foot contact length and 18% of forefoot contact width. When the longitudinal axis of the insole was plotted as the Y-axis and the transverse axis of the insole as X-axis, the slopes of the COP coordinates during stance phase was 6 degrees inward. Velocities of the COP during each functional rocker action were even and 22-27 cm/s. The changes of quantified COP parameters according to the biomechanical alteration of the foot were confirmed by high-heeled gait.

A study on new diagnostic criteria of H reflex

H reflex is known as a useful electrodiagnostic test in the diagnosis of S1 radiculopathy. But, only the latency difference has been the useful parameter by previously published conventional method. Under the assumption that the constant appearance of initial negative biphasic H wave is critical to study H reflex using parameters such as amplitude, area and shape, we developed a new method using parameters such as amplitude, area and shape. To validate our assumption and to compare the diagnostic values between the conventional method and the new one, we studies H reflex in 330 subjects. One hundred sixty-two subjects were studied by conventional method and 168 subjects were studied by our new method. There was no definite difference in diagnostic values between two methods by latency criteria. However, new method was more specific for S1 radiculopathy than conventional method by amplitude and area criteria. Parameters such as amplitude, area and shape can be used significantly only in the new method. Therefore, we suggest new diagnostic criteria of abnormal response as follows: (1) H latency difference over 1.0 msec and H/H amplitude ratio less than 0.5 or (2) H latency over 30 msec or (3) unilateral absent evoked H response.