Case report: Hand-arm vibration syndrome in a dental technician.

Occupational exposure to vibration using hand-held tools may cause hand-arm vibration syndrome (HAVS) among workers. We report the case of a 39-year-old lady with a 5-year work exposure to repetitive wrist movements and vibration from hand tools in the dental fabrication laboratory, working as a dental technician. She presented with a 3-year history of chronic pain over the wrists and positive symptoms of numbness and tingling in the hands, pain and discomfort of the fingers during cold exposure, and poor grip strength. Symptoms over the right hand were worse than the left. She is right-hand dominant. She had bilateral median nerve neuropathy at the wrist. Nerve conductive tests were consistent with minimal bilateral carpal tunnel syndrome. MRI showed evidence of soft tissue damage from repetitive strain injury of the right wrist. Neurosensory grading for hand-vibration syndrome (HAVS) using the Stockholm Workshop Scale (SWS) was performed and she was graded as Stage 1SN with numbness or tingling symptoms. Using the International Consensus Criteria (ICC) grading for HAVS, she was graded Stage N1 with numbness and/or tingling (symptoms) of finger. A workplace risk health assessment (WHRA) was performed, and exposure scores for her work tasks in dental fabrication and risk levels were determined using the HSE (Health and Safety UK) Assessment of Repetitive Tasks (ART) tool. The processes of teeth setting using dental burs (exposure score 23), divestment work with stone clippers (score 20), and use of pneumatic drills (score 21) were deemed high-risk activities for repetitive strain injury. The use of carving tools (score 12), packing with the use of flask clamps, and trimming (score 14) were classified as medium high-risk activities for repetitive strain injuries. Workplace modifications and workplace vibration exposure level monitoring protocols were subsequently established with the stabilization of the patient's symptoms.

Repetitive Transcranial Magnetic Stimulation for Motor Recovery After Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials With Low Risk of Bias.

OBJECTIVES: Repetitive transcranial magnetic stimulation (rTMS) has shown promising results in enhancing motor recovery after stroke, but nuances regarding its use, such as the impact of the type and site of stimulation, are not yet established. We aimed to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) with low risk of bias to investigate the effect of rTMS on motor recovery after both ischemic and hemorrhagic stroke. MATERIALS AND METHODS: Three databases were searched systematically for all RCTs reporting comparisons between rTMS (including theta-burst stimulation) and either no stimulation or sham stimulation up to August 19, 2022. The primary outcome measure was the Fugl-Meyer Assessment for Upper Extremity (FMA-UE). Secondary outcome measures comprised the Action Research Arm Test, Box and Block Test, Modified Ashworth Scale for the wrist, and modified Rankin Scale (mRS). RESULTS: A total of 37 articles reporting 48 unique comparisons were included. Pooled mean FMA-UE scores were significantly higher in the experimental group than the control group after intervention (MD = 5.4 [MD = 10.7 after correction of potential publication bias], p < 0.001) and at the last follow-up (MD = 5.2, p = 0.031). On subgroup analysis, the improvements in FMA-UE scores, both after intervention and at the last follow-up, were significant in the acute/subacute stage of stroke (within six months) and for patients with more severe baseline motor impairment. Both contralesional and ipsilesional stimulation yielded significant improvements in FMA-UE at the first assessment after rTMS but not at the last follow-up, while the improvements from bilateral rTMS only achieved statistical significance at the last follow-up. Among the secondary outcome measures, only mRS was significantly improved in the rTMS group after intervention (MD = -0.5, p = 0.013) and at the last follow-up (MD = -0.9, p = 0.001). CONCLUSIONS: Current literature supports the use of rTMS for motor recovery after stroke, especially when done within six months and for patients with more severe stroke at baseline. Future studies with larger sample sizes may be helpful in clarifying the potential of rTMS in poststroke rehabilitation.

Corpus Callosum-Mediated Interhemispheric Interactions in Cervical Spondylotic Myelopathy.

PURPOSE: The corpus callosum is crucial for interhemispheric interactions in the motor control of limb functions. Human and animal studies suggested spinal cord pathologies may induce cortical reorganization in sensorimotor areas. We investigate participation of the corpus callosum in executions of a simple motor task in patients with cervical spondylotic myelopathy (CSM) using transcranial magnetic stimulation. METHODS: Twenty patients with CSM with various MRI grades of severity of cord compression were compared with 19 normal controls. Ipsilateral silent period, contralateral silent period, central motor conduction time, and transcallosal conduction time (TCT) were determined. RESULTS: In both upper and lower limbs, TCTs were significantly increased for patients with CSM than normal controls ( p < 0.001 for all), without side-to-side differences. Ipsilateral silent period and contralateral silent period durations were significantly increased bilaterally for upper limbs in comparison to controls ( p < 0.01 for all), without side-to-side differences. There were no significant correlations of TCT with central motor conduction time nor severity of CSM for both upper and lower limbs ( p > 0.05 for all) bilaterally. CONCLUSIONS: Previous transcranial magnetic stimulation studies show increased motor cortex excitability in CSM; hence, increased TCTs observed bilaterally may be a compensatory mechanism for effective unidirectional and uniplanar execution of muscle activation in the distal limb muscles. Lack of correlation of TCTs with severity of CSM or central motor conduction time may be in keeping with a preexistent role of the corpus callosum as a predominantly inhibitory pathway for counteracting redundant movements resulting from increased motor cortex excitability occurring after spinal cord lesions.

Utility of Sensory Nerve Conduction Study in Radiologically Positive Lumbosacral Plexopathy.

MRI is the most appropriate imaging method for visual evaluation of lumbosacral plexopathy (LSP) and a reference for comparing with nerve conduction study (NCS). Eight patients with clinical, electrophysiological, and lumbosacral plexus MRI findings suggestive of LSP were prospectively recruited. Saphenous nerve abnormalities were present in seven patients (88%), compared to three for the superficial fibular (38%), and three for the sural nerve (38%). MRI showed tumor, hematoma, abscess, contrast enhancement, or hyperintense signals on the T2-weighted sequences. The SN has the highest yield in MRI positive LSP and may be a vital adjunct for electrophysiological evaluation of LSP.

Approach to headache disorders and the management of migraine: consensus guidelines from the Headache Society of Singapore, first edition (2023).

Headache disorders, particularly migraine, are one of the most common and disabling neurological disorders. There is a need for high-quality, accessible care for patients with headache disorders across all levels of the healthcare system in Singapore. The role of the Headache Society of Singapore is to increase awareness and advance the understanding of these disorders and to advocate for the needs of affected patients. In this first edition of local consensus guidelines, we focus on treatment approaches for headaches and provide consensus recommendations for the management of migraine in adults. The recommendations in these guidelines can be used as a practical tool in routine clinical practice by primary care physicians, neurologists and other healthcare professionals who have a common interest in headache disorders.

Parkinson's disease genome-wide association study-linked PARK16 variant is associated with a lower risk of cognitive impairment: A 4-year observational study.

BACKGROUND AND PURPOSE: A genome-wide association study-linked variant (PARK16 rs6679073) modulates the risk of Parkinson's disease (PD). We postulate that there may be differences in clinical characteristics between PARK16 rs6679073 carriers and noncarriers. In a prospective study, we investigate the clinical characteristics between PARK16 rs6679073 A allele carriers and noncarriers over 4 years. METHODS: A total of 204 PD patients, comprising 158 PARK16 rs6679073 A allele carriers and 46 noncarriers, were recruited. All patients underwent motor and nonmotor symptom and cognitive assessments yearly over 4 years. RESULTS: PARK16 rs6679073 carriers were less likely to have mild cognitive impairment (MCI) compared to noncarriers at both baseline (48.1% vs. 67.4%, p = 0.027) and 4-year follow-up (29.3% vs. 58.6%, p = 0.007). CONCLUSIONS: PD PARK16 rs6679073 carriers had significantly lower frequency of MCI in a 4-year follow-up study, suggesting that the variant may have a neuroprotective effect on cognitive functions.

Biomarker characterization of clinical subtypes of Parkinson Disease.

The biological underpinnings of the PD clusters remain unknown as the existing PD clusters lacks biomarker characterization. We try to identify clinical subtypes of Parkinson Disease (PD) in an Asian cohort and characterize them by comparing clinical assessments, genetic status and blood biochemical markers. A total of 206 PD patients were included from a multi-centre Asian cohort. Hierarchical clustering was performed to generate PD subtypes. Clinical and biological characterization of the subtypes were performed by comparing clinical assessments, allelic distributions of Asian related PD gene (SNCA, LRRK2, Park16, ITPKB, SV2C) and blood biochemical markers. Hierarchical clustering method identified three clusters: cluster A (severe subtype in motor, non-motor and cognitive domains), cluster B (intermediate subtype with cognitive impairment and mild non-motor symptoms) and cluster C (mild subtype and young age of onset). The three clusters had significantly different allele frequencies in two SNPs (Park16 rs6679073 A allele carriers in cluster A B C: 67%, 74%, 89%, p = 0.015; SV2C rs246814 T allele distribution: 7%, 12%, 25%, p = 0.026). Serum homocysteine (Hcy) and C-reactive protein (CRP) levels were also significantly different among three clusters (Mean levels of Hcy and CRP among cluster A B C were: 19.4 ± 4.2, 18.4 ± 5.7, 15.6 ± 5.6, adjusted p = 0.005; 2.5 ± 5.0, 1.5 ± 2.4, 0.9 ± 2.1, adjusted p < 0.0001, respectively). Of the 3 subtypes identified amongst early PD patients, the severe subtype was associated with significantly lower frequency of Park16 and SV2C alleles and higher levels of Hcy and CRP. These biomarkers may be useful to stratify PD subtypes and identify more severe subtypes.

Recurrent ipsilateral hemiparesis in a patient with both uncrossed corticospinal tracts and reorganization of cortical motor areas - An opportune visitation of the motor tracts.

We report the case of a patient who experienced recurrent ipsilateral hemiparesis in the setting of predominantly-uncrossed corticospinal tracts, with concomitant neuronal reorganization of the cortical motor maps, and the presence of aberrant interhemispheric connections. Their presence was supported by our results from diffusion tensor imaging tractography, functional magnetic resonance imaging, and transcranial magnetic stimulation. To our knowledge, this has never been reported before, and provides valuable insights into the mechanisms behind post-stroke motor recovery.

Prognostic factors of key outcomes for motor neuron disease in a multiracial Asian population.

BACKGROUND: Knowledge of prognostic factors related to the survival of Motor Neuron Diseases (MND) remains scarce in Southeast Asia. PURPOSE: To determine potential prognostic factors for survival, need for feeding and ventilation support in MND patients in a multi-racial Asian population. METHODS: One hundred and four MND patients from the Singapore General Hospital (SGH) between January 2004 and December 2017 were reviewed. All relevant clinical data, demographic information were collected. Kaplan-Meier and Cox regression model were performed to identify potential prognostic factors for crucial outcomes (survival, need for feeding support and ventilation support). RESULTS: Mean age of onset was 59.54 ± 10.91 years, Mean age of onset in Malays was significantly younger than that of other ethnic groups (Malay: 54.18 ± 12.95 years; Non-Malay: 60.39 ± 10.38 years, p = 0.035). Fifty six of the male and 33of the female were diagnosed with ALS (90.3% vs. 78.6% p = 0.048). Mean overall survival duration from symptom onset was significantly longer in female than male patients (female: 39.2 ± 29.04 months; male: 29.4 ± 24.06 months, P = 0.03). In the multivariable Cox regression model, bulbar onset (aHR = 5.28, p = 0.035) correlated with poor survival outcome while longer duration from onset to second symptom (aHR = 0.96, P = 0.037) indicated better survival. CONCLUSIONS: Bulbar onset was a significant risk predictor for survival. Slower disease progression correlated with better outcomes. Age of onset may differ among ethnic groups. Male patients are more likely to develop Amyotrophic Lateral Sclerosis (ALS) and have shorter survival duration.

Intraoperative Motor Evoked Potential Improvement in Cervical Spondylotic Myelopathy: Comparison of Cortical Stimulation Parameters.

BACKGROUND AND PURPOSE: Intraoperative monitoring of the motor pathways is a routine procedure for ensuring the integrity of descending motor tracts during spinal surgery. Intraoperative motor evoked potential improvement (MEPI) may be associated with a better postsurgical outcome in cervical spondylotic myelopathy (CSM). To compare the efficacy of two cortical stimulation parameters in eliciting MEPI intraoperatively during CSM surgery. METHODS: We studied 69 patients who underwent decompression surgery for CSM over a 9-month period using either 5 (Group 1) or 9 (Group 2) stimuli. MEPI was defined as the increase in the amplitude of MEPs from baseline at the end of CSM surgery just prior to skin closure. RESULTS: An MEPI of 100% from baseline was observed in 10 patients (53%) in Group 1 and 36 patients (72%) in Group 2. Comparisons of the baseline mean MEP amplitudes of muscles bilaterally between Groups 1 and 2 did not reveal any significant differences. Supramaximal stimulation showed that a significantly higher mean intensity was required for Group 1 than for Group 2. CONCLUSIONS: MEPI is observed in a much larger proportion of cervical decompression surgery cases than previously thought. Intraoperative MEPI with longer-train cortical stimulation may reflect adequacy of decompression and provide additional guidance for the surgical procedure.

Impact of Cryotherapy on Sensory, Motor, and Autonomic Neuropathy in Breast Cancer Patients Receiving Paclitaxel: A Randomized, Controlled Trial.

Introduction: We conducted a randomized controlled trial evaluating the efficacy and tolerability of cryotherapy in preventing chemotherapy-induced peripheral neuropathy (CIPN) in patients with early breast cancer receiving neo/adjuvant weekly paclitaxel. Methods: Patients were recruited from the National Cancer Centre Singapore and randomized (1:1) to receive either cryotherapy or usual care. Cryotherapy was applied as frozen gloves and socks on all extremities from 15 min before paclitaxel until 15 min post-infusion every cycle. Efficacy was measured by patient-reported outcomes (Patient Neurotoxicity Questionnaire [PNQ] and EORTC QLQ-CIPN20) and electrophysiological assessments. The primary endpoint was PNQ severity at 2 weeks after 12 cycles of weekly paclitaxel. Results: A total of 46 patients were recruited, of which 8 dropped out before paclitaxel treatment, leaving 38 evaluable. There was no significant difference in PNQ severity between cryotherapy and usual care at 2 weeks after paclitaxel treatment (sensory: p = 0.721; motor: p = 1.000). A benefit was observed at 3 months post-paclitaxel based on PNQ (sensory: 14.3 vs. 41.2%, p = 0.078; motor: 0 vs. 29.4%, p = 0.012) and CIPN20 (sensory: ß = -3.6, 95%CI = -10.5-3.4, p = 0.308; motor: ß = -7.3, 95%CI = -14.6-0, p = 0.051). Additionally, cryotherapy subjects have lower CIPN20 autonomic score (ß = -5.84, 95%CI = -11.15 to -0.524, p = 0.031) and higher sympathetic skin response hand amplitudes (ß = 0.544, 95%CI = 0.108-0.98, p = 0.014), suggesting possible autonomic benefits from cryotherapy. Temporary interruption with cryotherapy occurred in 80.9% of the subjects due to cold intolerance. Conclusions: There is insufficient evidence that cryotherapy prevents sensory neuropathy which may be due to the high rates of cryotherapy interruption in this study. The autonomic benefits of cryotherapy should be further investigated with appropriate outcome measures. Clinical Trial Registration: ClinicalTrials.gov: NCT03429972.

Stiff Person Syndrome Associated with Compartment Syndrome.

Stiff person syndrome (SPS) is a rare and disabling neurological disorder of autoimmune origin, characterized by progressive stiffness and muscle spasms affecting the axial and limb muscles, most frequently associated with antibodies against glutamic acid decarboxylase. We describe a patient who presented initially with compartment syndrome and was later diagnosed with SPS. This is the first case report of SPS possibly presenting initially with compartment syndrome. This case illustrates the importance of recognizing that patients with SPS may present with varied manifestations, including compartment syndrome, which by itself is a medical emergency.

Parkinson's disease GWAS-linked Park16 carriers show greater motor progression.

BACKGROUND: Data on the long-term motor outcomes of genome-wide association study (GWAS)-linked Parkinson disease (PD) carriers are useful for clinical management. OBJECTIVES: To characterise the association between GWAS-linked PARK16 gene variant and disease progression in PD over a 9-year time frame. METHODS: Over a 9-year period, carriers of PARK16 rs11240572 variant and non-carriers were followed up and evaluated using the modified Hoehn and Yahr (H&Y) staging scale and Unified Parkinson's Disease Rating Scale (UPDRS) part III. A longitudinal, linear mixed model was performed to compare the changes of H&Y staging scale, UPDRS motor score and UPDRS subscores between the two groups. RESULTS: A total of 156 patients (41 PARK16 carriers and 115 non-carriers) were evaluated and followed up for up to 9 years. Using longitudinal linear mixed model analysis, there was a greater rate of deterioration in the motor function as measured by the UPDRS scores compared with non-carriers after 5 years from the date of diagnosis (p=0.009). In addition, we demonstrated that PARK16 variant carriers had worse gait scores (p=0.043) and greater motor progression than non-carriers after 6 years based on the modified H&Y staging scale (p=0.040). CONCLUSIONS: In a 9-year longitudinal study, we demonstrated that PD PARK16 variant carriers exhibited greater motor progression after 5 years of disease compared with non-carriers, suggesting that GWAS-linked gene variants may influence disease progression over time. Closer monitoring and management of these higher risk patients can facilitate a better quality of life.

Four-Year Longitudinal Study of Motor and Non-motor Symptoms in LRRK2-Related Parkinson's Disease.

Objectives: In a prospective 4-year study, we evaluated the progression of motor and non-motor symptoms in Parkinson's disease (PD) patients with Asian-specific LRRK2 risk variants and non-carriers. Methods: A total of 202 patients with PD, including 133 risk variant carriers and 69 non-carriers, were followed up and evaluated using the Modified Hoehn and Yahr staging scale, Unified Parkinson's Disease Rating Scale part III, Non-motor Symptom Scale, Parkinson's disease Questionnaire-39 item version. Means of generalized estimating equation model was performed to compare the differences from baseline between LRRK2 risk variant carriers and non-carriers. Results: Our longitudinal analysis revealed that risk variant carriers exhibited greater progression than non-carriers after 4 years based on the modified Hoehn and Yahr staging scale (risk variants carriers, 0.65; non-carriers, 0.06; P = 0.041). Meanwhile, Unified Parkinson's Disease Rating Scale gait and posture score in risk variant carriers also showed greater increase than that in non-carriers, although the difference was not statistically significant. Non-carriers experienced a transient improvement in non-motor symptoms at the early stage of PD, as scores at visit two significantly reduced compared to baseline in Non-motor Symptom Scale domain 3 (mood/apathy), Parkinson's disease Questionnaire-39 item version domain 3 (emotional well-being), and frequency of NMS in non-carriers but not in risk variants carriers. Conclusions: PD gene risk variant carriers were more likely to progress faster in their motor severity than non-carriers. There were transient differences in certain non-motor symptoms and quality of life in carriers. However, more studies are warranted to assess the association of PD risk variants and progression of non-motor symptoms.

Systematic re-evaluation of intraoperative motor-evoked potential suppression in scoliosis surgery.

BACKGROUND: Motor- (MEP) and somatosensory-evoked potentials (SSEP) are susceptible to the effects of intraoperative environmental factors. METHODS: Over a 5-year period, 250 patients with adolescent idiopathic scoliosis (AIS) who underwent corrective surgery with IOM were retrospectively analyzed for MEP suppression (MEPS). RESULTS: Our results show that four distinct groups of MEPS were encountered over the study period. All 12 patients did not sustain any neurological deficits postoperatively. However, comparison of groups 1 and 2 suggests that neither the duration of anesthesia nor speed of surgical or anesthetic intervention were associated with recovery to a level beyond the criteria for MEPS. For group 3, spontaneous MEPS recovery despite the lack of surgical intervention suggests that anesthetic intervention may play a role in this process. However, spontaneous MEPS recovery was also seen in group 4, suggesting that in certain circumstances, both surgical and anesthetic intervention was not required. In addition, neither the duration of time to the first surgical manoeuver nor the duration of surgical manoeuver to MEPS were related to recovery of MEPS. None of the patients had suppression of SSEPs intraoperatively. CONCLUSION: This study suggests that in susceptible individuals, MEPS may rarely occur unpredictably, independent of surgical or anesthetic intervention. However, our findings favor anesthetic before surgical intervention as a proposed protocol. Early recognition of MEPS is important to prevent false positives in the course of IOM for spinal surgery.