Headache in hemifacial spasm patients

OBJECTIVES

To assess prevalence of headaches in patients with hemifacial spasm. To determine whether hemifacial spasm provokes headaches and identifies predictive factors. To evaluate whether botulinum toxin given for hemifacial spasm improves headaches.

METHODS

Seventy patients with hemifacial spasm were evaluated for headaches. The relationship of headaches with hemifacial spasm, impact on quality of life (HIT-6), and improvement in headaches from botulinum toxin was recorded. Data on duration, severity, and impact on quality of life (HFS-7) of hemifacial spasm were collected.

RESULTS

Hemifacial spasm-related headache was significantly associated with increased hemifacial spasm severity (P < 0.001) and HIT-6 (P = 0.024). Greater hemifacial spasm severity was predictive of hemifacial spasm-related headache (P = 0.006, OR 19.1, 95% CI 2.35-155.64). Botulinum toxin (BTX) for hemifacial spasm improved hemifacial spasm-related headaches (P < 0.001).

CONCLUSIONS

Hemifacial spasm can complicate headaches, particularly in patients with greater hemifacial spasm severity. Individually tailored regimens of botulinum toxin may be indicated in these patients.

Phenotype in parkinsonian and nonparkinsonian LRRK2 G2019S mutation carriers

OBJECTIVES

Using a family study design, we describe the motor and nonmotor phenotype in probands with LRRK2 G2019S mutations and family members and compare these individuals to patients with idiopathic Parkinson disease (iPD) and unrelated controls.

METHODS

Probands with G2019S mutations and their first-degree relatives, subjects with iPD, and unrelated control subjects were identified from 4 movement disorders centers. All underwent neurologic examinations and tests of olfaction, color vision, anxiety, and depression inventories.

RESULTS

Tremor was more often a presenting feature among 25 individuals with LRRK2-associated PD than among 84 individuals with iPD. Subjects with LRRK2-PD had better olfactory identification compared with subjects with iPD, higher Beck Depression Inventory scores, and higher error scores on Farnsworth-Munsell 100-Hue test of color discrimination. Postural or action tremor was more common among 29 nonmanifesting mutation carriers compared with 53 noncarriers within the families. Nonparkinsonian family members had higher Unified Parkinson's Disease Rating Scale motor scores, more constipation, and worse color discrimination than controls, regardless of mutation status.

CONCLUSIONS

Although tremor is a more common presenting feature of LRRK2-PD than iPD and some nonmotor features differed in degree, the phenotype is largely overlapping. Postural or action tremor may represent an early sign. Longitudinal evaluation of a large sample of nonmanifesting carriers will be required to describe any premotor phenotype that may allow early diagnosis.

Lingo2 variants associated with essential tremor and Parkinson's disease

LINGO2, a member of LRR gene family, has been linked with both Essential tremor (ET) and Parkinson's disease (PD). However, there is a lack of conclusive evidence regarding the etiologic role of LINGO2 genetic variants. We investigated the association of LINGO2 variants with ET and PD in two independent Asian countries. A total of 1,262 subjects comprising 499 controls, 436 PD patients, and 327 ET patients were included. Eight LINGO2 variants, including four single-nucleotide polymorphisms (SNPs) and four coding variants, were initially analyzed in one Asian population. SNPs that showed positive association were then replicated in the second independent Asian population, and a pooled analysis was carried out. Out of the eight variants, two SNPs (rs7033345 and rs10812774) revealed significant or strong positive trend in the first Asian population, and these were analyzed in the second Asian population. In the pooled analysis, the CC genotype at rs7033345 had a higher risk of developing PD (OR = 1.67, 95% CI = 1.18, 2.35, p = 0.003) and ET (OR = 1.50, 95% CI = 1.02, 2.20, p = 0.04) under a recessive model. The C allele at rs10812774 increased the risk of ET (OR = 1.56 95% CI = 1.10, 2.22, p = 0.01) via a recessive model. The effect size and direction of trend were in the same direction in each of the two populations. Our study demonstrated for the first time that rs7033345 is associated with PD and ET and rs10812774 with ET among Asians, suggesting that LINGO2 might act as a susceptibility gene for both conditions.

Analysis of GWAS-linked loci in Parkinson disease reaffirms PARK16 as a susceptibility locus

OBJECTIVE

A genome-wide association study (GWAS) in the Japanese population identified 2 new Parkinson disease (PD) susceptibility loci on 1q32 (PARK16) (OMIM 613164) and BST1. We analyzed single nucleotide polymorphism (SNPs) located at the GWAS-linked loci (PARK16, PARK8, PARK1, and BST1) in a Chinese population and also conducted a meta-analysis in Asians by pooling 2 independent replication studies from Japan.

METHODS

We conducted an analysis of 13 SNPs associated with PD GWAS-linked loci in 2 case-control cohorts comprised of 1,349 ethnic Chinese subjects.

RESULTS

PARK16, PARK8, and PARK1 loci but not BST1 were found to be associated with PD. PARK16 SNPs were associated with a decreased risk while PARK1 and PARK8 SNPs were associated with an increased risk of PD. A pooled analysis of our Chinese cohorts and 2 Japanese replication cohorts involving 1,366 subjects with PD and 16,669 controls revealed robust association with these 3 loci and also BST1. There was a trend toward a stronger protective effect of SNPs at the PARK16 locus in sporadic PD compared to familial cases and in older compared to younger subjects.

CONCLUSIONS

Our study reaffirms the role of GWAS-linked loci in PD in Asian subjects and the strength of association is similar between Chinese and Japanese subjects. Efforts to elucidate the associated gene within PARK16 locus are warranted.

Validity of family history in essential tremor

In this study, we found the sensitivity and specificity of family history data given by essential tremor (ET) patients to be 43.3% and 94.4%. Compared to relatives with less severe tremor (tremor score <24), those with more severe tremor (tremor score 24) were more likely to be identified by the ET probands (8/8 vs. 5/22, p=0.001, chi2 14.3). Our study suggests that family history information reported by ET patients was inaccurate, and poorly validated. Clinical and genetic studies in ET should take the limitation of family history data into consideration.

Mycophenolate mofetil – as an adjunctive immunosuppressive therapy in refractory myasthenia gravis: The Singapore experience

We report our experience, using mycophenolate mofetil (MyM) as an adjunctive immunosuppressive therapy in patients with severe, refractory and high dose steroid-dependent myasthenia gravis (MG). Five patients were commenced on MyM in addition to other immunosuppressive therapies. All had significant clinical improvement and no subsequent myasthenic crisis requiring intensive care unit admission. MyM was well tolerated and no serious adverse effects were observed. MyM is an effective adjunctive therapy for the treatment of severe, refractory and steroid-dependent MG in our experience.

Clinical features of childhood onset essential tremor

Childhood onset essential tremor (ET) is uncommon. It is not clear as to whether ethnicity-specific differences may influence the phenotypic features. To determine the frequency and clinical characteristics of childhood ET in a tertiary referral center. In a prospective evaluation of 120 consecutive ET patients in a movement disorders clinic, we found a 15.5% (19) frequency of childhood onset ET patients. The mean age of onset and mean age was 10.8 +/- 4.1 (6-16) years and 25.7 +/- 15.0 (16-73) years consisting of 73.6% (14/19) men and 26.4% (5/19) women. A positive family history of ET was present in 11 of 19 (52.6%). Presence of a head tremor was observed in 2/19 (10.5%). We highlighted a relatively high frequency (15,5%) of childhood ET in our Asian cohort. In addition, we drew attention to the male preponderance and the low frequency of head tremor in childhood ET corroborating study findings in white ET patients. These observations appear to transcend ethnic and cultural differences and lend further support that gender difference may play a role in the pathogenesis and expression of ET.

Knowledge about the genetics of essential tremor in patients and their relatives

In a face-to-face questionnaire-based survey involving a total of 111 essential tremor (ET) patients and their relatives, we demonstrated a general lack of genetic insight amongst our study subjects. There was no significant correlation between genetic knowledge of ET and age, level of education, disease duration or severity. A proactive effort is needed to encourage physicians managing ET patients to incorporate genetic information and education into their practice.

Exploring the relationship between caffeine intake and essential tremor

BACKGROUND

It has been suggested that environmental factors may be associated with essential tremor (ET). This study was carried out to evaluate the association of caffeine intake with ET.

METHOD

In a case control study, patients diagnosed with ET and healthy controls underwent a standardized questionnaire interview to evaluate the exposure to coffee and tea intake. A multivariate logistic regression analysis was carried out to evaluate the association of caffeine intake and other environmental factors with risk of ET.

RESULTS

179 subjects including 79 ET patients and 100 controls matched for age, gender and ethnicity were included in the analysis. Univariate analysis revealed that caffeine consumption in ET patients was higher than control group (median and 90th percentile range: 2300 (0, 9000) mg-years versus 1500 (0, 6090) mg-years, p=0.01). However, the multivariate logistic regression analysis demonstrated that caffeine was no longer a significant factor associated with ET (p=0.119). There was no significant correlation between amount of caffeine intake and disease duration (Spearman's r=0.194; p=0.202) or total tremor score (Spearman's r=0.045; p=0.771) in ET patients.

CONCLUSION

Caffeine consumption was not associated with risk of ET in our study population. Further studies are needed to investigate the significance of gene-environmental interaction in ET.

Non-motor manifestations in essential tremor: use of a validated instrument to evaluate a wide spectrum of symptoms

INTRODUCTION

Recent studies suggest an association between non-motor symptoms and essential tremor (ET). Few studies have assessed psychological symptoms in ET. These studies were limited to western white populations and utilized scales that were specific to only one or two psychiatric domains. By contrast, the Symptom Checklist-90R (SCL-90R) is a validated clinical scale to screen for symptoms related to a spectrum of nine different psychological domains.

OBJECTIVE

To determine whether a wide spectrum of non-motor manifestations is associated with ET in patients in an Asian cohort.

METHODS

Consecutive ET patients and a group of control subjects were evaluated using the SCL-90R, which is comprised of items in nine major symptom dimensions and three global indices, including the positive symptom distress index.

RESULTS

ET patients (N = 84) and controls (N = 78) were similar in age (50.0+/-18.0 vs 46.0+/-14.4 years), gender and other demographic variables. ET patients had higher scores in three of nine major symptom dimensions: anxiety, phobic anxiety (p < 0.0005) and psychoticism (p = 0.005). In multivariate analysis, the anxiety (p < 0.0005) and the positive symptom distress index scores (p < 0.0005) were greater in ET patients compared to controls after adjusting for sex, age, marital status and educational level. The severity, but not duration of ET was correlated with the severity of anxiety symptoms.

CONCLUSIONS

Utilizing the SCL-90R, we highlighted that ET patients reported more non-motor symptoms than healthy controls. The more frequent occurrence of anxiety symptoms in our Asian cohort extends the observation that such non-motor manifestations should be considered in the clinical management of ET.

The role of clinical neurophysiology in bioterrorism

Chemical and biological agents have been used as weapons of mass destruction for a long time and presents as a serious threat to mankind. They have been used in many great wars and terrorist attacks with devastating results. The knowledge about these weapons of mass destruction is crucial to health care providers. Early recognition of the clinical characteristics of poisoning as a result of these chemical and biological agents is important to initiate appropriate therapy and minimizing casualties. Neurophysiological investigations when integrated with clinical features are helpful in early identification of some of these agents, especially when serological confirmation is not rapidly available. In this review, we have focused on chemical and biological weapons, which affect the nervous system and the role of clinical neurophysiology in such conditions.

Posterior antebrachial cutaneous nerve conduction study in radial neuropathy

Radial neuropathy most commonly occurs as a result of external compression at the spiral groove region. The posterior antebrachial cutaneous nerve (PACN) conduction study was performed in 15 consecutive patients with radial palsy. Unilateral PACN abnormalities were present in 11 patients. A normal PACN study was correlated with clinical improvement at 3 months. Conversely, PACN abnormality was correlated with radial motor axon loss and a poorer prognosis. The PACN study is a simple adjunct which provides additional information relating to the diagnosis and prognosis of radial lesions.

SUNCT syndrome in association with persistent Horner syndrome in a Chinese patient

This is the first case report of a chinese patient with SUNCT (shortlasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing) presenting with persistent Horner's syndrome. She had episodic, brief, right periorbital pain in association with ipsilateral eye injection, lacrimation and rhinorrhea as well as persistent ipsilateral miosis and ptosis. She had partial response to a combination of indomethacin and carbamazepine therapy.

Posterior antebrachial cutaneous nerve conduction studies in normal subjects

OBJECTIVE

The posterior antebrachial cutaneous (PABC) nerve is a sensory nerve that branches out from the radial nerve at the level of the spiral groove. Thus it can be affected in a radial nerve lesion at or proximal to its origin in the spiral groove. However, there has been limited knowledge about the normal values of PABC nerve conduction studies. This study was done to determine these normal values.

METHODS

Sixty-three healthy adults (23 males) with a mean age of 41.5+/-10.6 (range, 20-90) years were recruited with informed consent. A total of 126 nerves were studied. The nerve conduction studies were performed using a Dantec Counterpoint EMG machine (Dantec, Skovlunde, Denmark).

RESULTS

The mean+/-standard deviation values for the onset as well as peak latency, conduction velocity, amplitude and side-to-side amplitude ratio were 2.07+/-0.16 (range, 1.80-2.60) ms, 2.35+/-0.15 (range, 2.05-2.90) ms, 58.21+/-4.29 (range, 46.15-66.67) m/s, 6.10+/-2.11 (range, 2.90-13.00) microV and 0.83+/-0.12 (range, 0.60-0.99), respectively. There was a significant correlation between the subject age and the PABC onset and peak latencies as well as the amplitudes.

CONCLUSIONS

The PABC nerve is assessable for nerve conduction studies and these normal values may be useful in evaluation of patients with suspected radial nerve lesions.

The use of nerve conduction studies in determining the short-term outcome of Bell's palsy

Bell's palsy is a common neurological problem causing considerable loss of self-esteem among patients. A prospective observational study was conducted to determine the short-term outcome of Bell's palsy at 1 month and 2 months after the onset and the relationship between these outcomes with facial nerve degeneration. We also determined if gender, age, diabetes, systolic and diastolic blood pressure influence the severity of facial nerve degeneration and the clinical outcome at 2 months after the onset. After clinically grading the newly diagnosed unilateral Bell's palsy patients using the House-Brackmann facial nerve grading system, nerve conduction studies of the facial nerve were done to determine the severity of facial nerve degeneration. The recovery of the facial paralysis was clinically graded again at the end of 1 month and 2 months from the onset. A total of 37 patients were recruited. There was a strong positive correlation between facial nerve degeneration and the clinical outcome of Bell's palsy at 1 month (r = 0.794; p < 0.0005) and 2 months (r = 0.732; p < 0.0005) after the onset. There was no significant correlation between either the facial nerve degeneration or the clinical outcome at 2 months with the patients' age (p = 0.288 and p = 0.799 respectively), systolic blood pressure (p = 0.425 and p = 0.933 respectively) or diastolic blood pressure (p = 0.243 and p = 0.579 respectively). Neither the severity of facial nerve degeneration nor the clinical outcome at 2 months were significantly different between male and female patients (p = 0.460 and p = 0.725 respectively) or diabetic and non-diabetic patients (p = 0.655 and p = 0.655 respectively).

Clinical and immunological studies on persons exposed to Parthenium hysterophorus L

Studies on 300 persons subjected by occupational hazard to the allergenic weed, Parthenium hysterophorus L. for periods ranging from 3 to 12 months revealed that 4% of them developed contact dermatitis of the exposed parts of the body, while 56% of them got sensitized to the weed without apparently exhibiting any dermatitis. None of them suffered from allergic manifestations like rhinitis or bronchial asthma during the period of study which extended for 2 years.