PARK2 Patient Presenting with Dopa-Responsive Dystonia.

We report a 34-year-old female PARK2 patient presenting with dopa-responsive dystonia (DRD). She noticed difficulty in raising her foot while walking at the age of 24. Her lower limb symptoms were identified as dystonia later, and she was started on Menesit, which resulted in improvement of her symptoms. She was diagnosed as DRD and has been on continuous treatment since then. The specific binding ratio (SBR) of 123I FP-CIT SPECT was significantly lower than those of controls of the same age, but 123I-meta-iodobenzylguanidine myocardial scintigraphy showed a normal heart to mediastinum ratio. The Montreal Cognitive Assessment, Japanese version, was normal for her age. DRD is an inherited dystonia that typically begins during childhood and may be caused by mutations of the GCH1 (GTP cyclohydrolase), SPR (sepiapterin reductase), or TH (tyrosine hydroxylase) genes. Our patient was diagnosed as PARK2, known as autosomal-recessive juvenile Parkinson's disease, based on genetic analysis. Although there was no family history of the disease, the decrease in SBR of 123I FP-CIT SPECT enabled us to diagnose PARK2 and to differentiate this from DRD due to other genetic disorders.

Levodopa-Responsive Primary Slow Orthostatic Tremor: A Premotor Sign of Parkinson's Disease?

We present a case of primary orthostatic tremor (OT) responsive to dopaminergic medication. The patient was a 62-year-old woman, who had leg tremor on standing for 2 years. No parkinsonian or other neurological signs were observed. Surface electromyography of the quadriceps muscles showed regular 5-6 Hz muscle discharges. [123I]-FP-CIT DAT-SPECT imaging revealed decreased specific binding ratio values in the striatum compared with age-matched controls. Her leg tremor almost completely disappeared following administration of levodopa 200 mg and pramipexole 0.75 mg. Since her OT with low-frequency discharge was responsive to dopaminergic medication, we speculate that it may be a premotor sign of Parkinson's disease.

What is the most sensitive test for diagnosing carpal tunnel syndrome?

OBJECTIVE: To compare sensitivities between 7 principal nerve conduction studies (NCS) for diagnosing carpal tunnel syndrome (CTS). METHOD: In 104 CTS and 64 control hands, following "Standard" NCSs were examined simultaneously: (1) Median sensory NCS; (2) segmental wrist-palm sensory NCS; (3) 4th digit latency difference; (4) 1st digit latency difference and (5) palmar mixed nerve latency difference. As "Guideline" and "Option" NCSs, we also examined: (6) Median motor distal latency and (7) second lumbrical-interossei latency difference (2LILD). Forty-nine CTS hands were divided into a milder subgroup only if action potentials could be recorded using all tests applied; that is, those with any absent potentials were excluded from the subgroup. Sensitivities and specificities were compared to each other. RESULTS: In all CTS hands, the sensitivity of test (1), (2), (3), (4), (5), (6) and (7) was 83, 87, 92, 90, 90, 70 and 92%, respectively. In the milder subgroup, it was 67, 78, 84, 82, 84, 43, and 84% in the same order. There was no statistical difference between Standard tests and 2LILD. Specificities of all tests were over 95%. CONCLUSIONS: All "Standard" tests and 2LILD have high comparable sensitivities. Therefore, 2LILD should be recommended as "Standard" NCS detecting CTS.

Relationship between event-related desynchronization and cortical excitability in healthy subjects and stroke patients.

OBJECTIVE: Relation between cortical excitability and magnitudes of event-related dysynchronizaton (ERD) has not been clarified. This study was investigated that relationshp between cortical excitability and ERD magnitudes in healthy subjects and stroke patients. METHODS: Ten healthy subjects and four patients with stroke participated in this study. EEGs were recorded over the sensorimotor cortex (left hemisphere in healthy subjects; damaged hemisphere in stroke subjects) to calculate ERD during motor imagery,. Motor-evoked potential (MEP) induced by single-pulse transcranial magnetic stimulation over the primary motor cortex was recorded from the first dorsal interosseus (FDI) muscle at ERD magnitudes of 10% and 30%. RESULTS: MEP significantly increased at 10% and 30% ERD (p<0.01) than that during rest in healthy subjects. The 30% ERD condition showed significantly higher MEP than that at 10% ERD (p<0.05). In stroke patients, MEP increased with ERD induced by motor imagery, but the change of MEP to ERD amplitude was critically different among the subject. CONCLUSION: ERD magnitude corresponds to corticospinal excitability increases in healthy subjects and patients with hemiplegic stroke. BCI based on motor imagery-induced ERD may be a potential rehabilitation strategy for patients with hemiplegic stroke.

Changes in cortical excitability during and just before motor imagery.

OBJECTIVE: Changes in cortical excitability during motor imagery were investigated in order to reveal the effect of hand dominance. During motor imagery, motor evoked potentials (MEPs) were recorded from the first dorsal interosseous (FDI) muscle of the dominant hand using transcranial magnetic stimulation (TMS). METHODS: Twelve healthy right-handed subjects participated. Three motor imagery tasks (MITs) were provided; dominant hand grasping, non-dominant hand grasping, and ankle dorsiflexion ipsilateral to the dominant hand. MEPs were also recorded from the FDI muscle of the non-dominant hand during the same tasks. RESULT: MEPs increased significantly in the dominant hand during MIT, just before MIT of the dominant hand, and prior to ankle dorsiflexion ipsilateral to the dominant hand. MEPs obtained from the FDI muscle of the dominant hand during MITs were greater than that obtained from the FDI muscle of the non-dominant hand. However, this difference was not significant. CONCLUSION: The left primary motor cortex (M1) was more excited than M1 during MITs of the hand muscles. Cortical excitability increased just before MIT of the contralateral hand and leg muscles.

Premotor potential study in carpal tunnel syndrome.

INTRODUCTION: Premotor potentials (PMPs) precede compound muscle action potentials evoked from the second lumbrical muscle after median nerve stimulation. Although PMP has been identified as a median sensory nerve action potential, few reports have documented the significance of PMP parameters for diagnosing carpal tunnel syndrome (CTS). METHODS: We investigated the relationships between PMP parameters and results of 6 standard median nerve conduction studies in 74 CTS hands. RESULTS: Significant correlations were noted in all comparisons. PMP conduction velocity was strongly correlated with the sensory conduction velocity between wrist and digit 2 (r(2) = 0.91). Moreover, PMP parameters were significantly correlated with neurophysiological severity of CTS. CONCLUSION: Measuring PMP parameters with a second lumbrical-interosseous study may be useful for diagnosing CTS.

Effect of low-frequency repetitive transcranial magnetic stimulation combined with physical therapy on L-dopa-induced painful off-period dystonia in Parkinson's disease.

Previous research has shown that low-frequency repetitive transcranial magnetic stimulation over the primary motor area and supplementary motor area can reduce L-dopa-induced dyskinesias in Parkinson's disease; however, it involved only patients with peak-dose or diphasic dyskinesia. We report a case of a patient with severely painful off-period dystonia in the unilateral lower limb who underwent 0.9-Hz subthreshold repetitive transcranial magnetic stimulation over contralateral primary motor area and supplementary motor area. Repetitive transcranial magnetic stimulation over the primary motor area significantly reduced the painful dystonia and walking disturbances but repetitive transcranial magnetic stimulation over the supplementary motor area did not. The cortical silent period also prolonged after repetitive transcranial magnetic stimulation over the primary motor area. At 5 mos of approximately once a week repetitive transcranial magnetic stimulation over the primary motor area, the Unified Parkinson's Disease Rating Scale motor score also improved. This report shows that repetitive transcranial magnetic stimulation over the inhibitory primary motor area can be useful for rehabilitating patients with Parkinson's disease with off-period dystonia and suggests that this treatment should be further verified in such patients.

Suprahyoid muscles motor evoked potentials in response to transcranial magnetic stimulation.

OBJECTIVE: The objective of this study was to reveal whether corticobulbar projection to the suprahyoid muscles (SHM) is contralateral or bilateral. METHODS: Thirty-nine healthy subjects between 27 and 77 years of age participated. All subjects underwent transcranial magnetic stimulation (TMS) in both cerebral hemispheres using surface EMG recording in bilateral SHM. One subject underwent TMS in cerebral hemisphere at the same time using needle and surface EMG recording in the contralateral and ipsilateral SHM. Eight subjects underwent TMS in both cerebral hemispheres using surface EMG recording in bilateral SHM, within 6 months of the first day. RESULTS: We obtained larger response in contralateral SHM than in ipsilateral SHM in the surface EMG recording. However, in the needle EMG recording, only contralateral SHM responses were evoked. TMS of either hemisphere evoked contralateral SHM motor-evoked potentials (MEPs) in all subjects [SHM latency: (left) 8.5 ± 0.9 ms, (right) 8.6 ± 1.1 ms]. There was no significant difference in latency between the first and second tests. In a case of right medullary infarction with left cortical stimulation, MEPs of right SMH were absent. CONCLUSION: Corticobulbar projections to the SHM appear to be dominated by contralateral projections in healthy adults.

The efficacy of supraglottic swallow as an indirect swallowing exercise by analysis of hyoid bone movement.

Supraglottic swallow (SGS) is one of the swallowing maneuvers used to enhance safe bolus passage into the esophagus and to avoid aspiration into the trachea. We examined the efficacy of SGS as an indirect swallowing exercise by quantifying hyoid bone movements during SGS. Videofluorography was used to analyze SGS in 10 healthy volunteers. SGS increased the hyoid bone posterior and superior excursion, and maintained these displacements longer, suggesting the effectiveness of the SGS as an indirect swallowing exercise. Thus SGS could be used not only as air way protection but also as an indirect swallowing exercise to strengthen the muscles adhering to the hyoid bone, and to expand the range of motion of the hyoid bone.

Changes in sensory functions after low-frequency repetitive transcranial magnetic stimulation over the motor cortex.

OBJECTIVE: To investigate changes in various sensory functions after low-frequency repetitive transcranial magnetic stimulation (rTMS) in healthy subjects. METHODS: A Neurometer® CPT/C was used to measure current perception threshold (CPT) values at frequencies of 2000, 250, and 5 Hz in the left index finger to assess the tactile sense, fast pain, and slow pain, respectively. Somatosensory evoked potentials (SEPs) elicited by left median nerve stimulation at the wrist were used to assess excitability in the primary sensory cortex (S1). These were investigated before and after rTMS (0.9 Hz, 0.9 ÁEresting motor threshold, 500 pulses) or sham rTMS over the right primary motor cortex (M1). RESULTS: All CPT values increased significantly and the P25-N33 of SEP amplitude decreased significantly after real rTMS, but not after sham rTMS; however, no correlations between the changes were observed. CONCLUSIONS: Low-frequency rTMS over the M1 provides global anesthetic effects and inhibits excitability in S1. The lack of correlation between these changes suggests that the anesthetic effects may not always relate to the excitability of S1; thus, the mechanisms responsible for the changes remain unclear. Nevertheless, these findings suggest that rTMS may be a useful strategy for treating intractable pain in rehabilitation medicine.