Outcome prediction value of nerve conduction studies for endoscopic carpal tunnel surgery.

OBJECTIVE: Carpal tunnel syndrome is the most common entrapment neuropathy. We explore the clinical use of nerve conduction study in the outcome prediction and preoperative selection for endoscopic carpal tunnel syndrome surgery. METHODS: Sixty-seven patients with carpal tunnel syndrome were prospectively enrolled. Each patient's clinical symptomatic score at baseline and 3 months postsurgery was compared with nerve conduction study parameters of distal motor latency, motor amplitude, motor conduction velocity, distal sensory latency, sensory amplitude, and sensory conduction velocity. A statistical logistic regression model was used to ascertain outcomes. RESULTS: Endoscopic surgery resulted in significant improvement for all four major symptoms pain, numbness, paresthesia, and weakness. From multivariate logistic regression, a shorter distal sensory latency is associated with a higher likelihood of a good outcome (P = 0.058; odds ratio, 0.912; 95% confidence interval, 0.828-1.0) only for paresthesia. The other factors were not found to be significant (all P > 0.10). The area under the curve (AUC) was 0.69 (95% confidence interval for AUC, 0.50-0.88). A cutoff of 6.0 ms or lower for sensory latency predicts for good outcome (in terms of paresthesia score) with the sensitivity/certainty of 84.6% and positive predictive value of 86.8%. A receiver operating characteristic analysis of baseline paresthesia score for good outcome of the paraesthesia domain showed that the AUC was 0.967 (95% confidence interval for AUC, 0-1.0). At a cutoff of baseline paraesthesia score of 4 or above, prediction for good outcome achieved a sensitivity of 87.2% and positive predictive value of 97.1%. CONCLUSIONS: A shorter distal sensory latency is associated with a higher likelihood of a good outcome for paraesthesia. In addition, patients with baseline of 4 or above had correlated with better surgical outcome than those with less severe symptoms. Our data thus suggest that surgical benefit is best seen in patients with moderate symptoms, in combination with electrophysiological evidence of early demyelination, as a possible therapeutic window.

Treatment outcome correlates with knowledge of disease in hemifacial spasm.

OBJECTIVES: Hemifacial spasm (HFS), a potentially disabling facial condition affects quality of life (QOL) and botulinum toxin is an effective treatment. No studies have examined whether a better level of knowledge of the disease would lead to an improved quality of life and treatment response in HFS. We examined the relationship between knowledge of disease with improvement in QOL following botulinum toxin treatment in HFS patients. PATIENTS AND METHODS: A total of 106 HFS patients (mean age of 56.8+/-9.9 years) were prospectively included. A baseline knowledge questionnaire and a validated disease-specific quality of life scale (HFS-7) were administered before and after botulinum toxin treatment. RESULTS: A better educational level was an independent predictor of high knowledge of HFS (p=0.02). Multivariate analysis using improvement in HFS-7 (total and subscore) as outcomes, and adjusting for age, gender, education, severity and duration of HFS, showed that high knowledge was predictive of a bigger improvement in HFS-7 total (p=0.03) and HFS-7 subscore (p=0.03). CONCLUSIONS: HFS patients with high knowledge of disease reported better improvement in QOL following botulinum toxin treatment. Better educational efforts will augment current medical and surgical treatments in improving QOL in HFS. Our findings could potentially be extended to many other medical conditions.

Evidence of increased odds of essential tremor in Parkinson's disease.

In a case control study using a standardized protocol, 600 subjects were evaluated for essential tremor (ET). We demonstrated that ET was significantly more frequent in patients with Parkinson's disease (PD) (12/204, 5.9%) compared to diseased controls (2/206, 1%) and healthy controls (1/190, 0.5%). A regression analysis with ET as outcome and group (either PD or healthy controls or diseased controls) as independent variable (adjusting for age and sex) revealed that PD had higher odds of having ET than diseased controls (OR = 5.43, 95% CI = 1.16, 25.39, P < 0.001) and healthy controls (OR = 10.87, 95% CI = 1.39, 85.15, P < 0.001). The low frequency of ET in our controls was further confirmed in a follow-up study in a group of age and gender matched general medical patients who attended an outpatient clinic (0% frequency). Eight of 204 PD (3.9%) compared to none of diseased (0%) (P = 0.004) and healthy controls (0%) (P = 0.008) had a prior diagnosis of ET. The duration of ET symptoms in patients with PD was 25.1 +/- 19.6 (range 3-60) years. A multivariate analysis demonstrated that a lower dose of levodopa (OR = 0.993, 95%CI for OR = 0.988, 0.997, P < 0.001) and a higher age of onset of disease (OR = 1.108, 95%CI for OR = 1.035, 1.187, P < 0.001) were associated with increased odds of PD with ET, compared to patients with PD without ET. In our Asian population, patients with PD were 5 to 10 times more likely to have ET compared to diseased and healthy controls, suggesting that the association of ET and PD is unlikely to be ethnicity-specific.

Case-control study of anxiety symptoms in hemifacial spasm.

In a case-control study, we evaluated symptoms in nine different psychological domains in hemifacial spasm (HFS; using the Symptom Checklist-90R [SCL-90R]) and found the anxiety score to be significantly greater in HFS compared to healthy controls in both the univariate (P = 0.004) and multivariate analysis (adjusted for sex, age, marital status, and educational level; P = 0.002). Similar findings were obtained when comparison was made with an independent group of outpatient controls. Compared to outpatient controls, the HFS patients had a higher mean Hamilton Anxiety Rating Score (HAM-A; 10.0 +/- 8.0 [range, 0 to 28] vs. 5.0 +/- 5.0 [range, 0 to 25]; P = 0.004), and 19.5% had HAM-A score of 18 or above compared to 3.8% in controls (P = 0.02). Among the HFS patients, the mean anxiety score in SCL-90R was significantly higher in those defined with mild to severe anxiety under HAM-A compared to those without anxiety (74.0 +/- 6.0 vs. 48.0 +/- 13.0) (P < 0.0005). There was good correlation of the anxiety score with the HAM-A in HFS patients (r = 0.915; P < 0.0001). HFS patients with anxiety reported significant improvement of their symptoms (mean HAM-A score 19.0 +/- 5.0 vs. 11.0 +/- 6.0; P = 0.001) following appropriate management. As stress and anxiety can aggravate HFS, diagnosis and early management of anxiety symptoms can improve quality of life in these patients.

Functional COMT variant predicts response to high dose pyridoxine in Parkinson's disease.

Pyridoxal-5-phosphate, the biological active form of pyridoxine, is a cofactor for dopa-decarboxylase (DDC) enzyme. Pyridoxine may augment the conversion of levodopa to dopamine in the periphery and therefore decrease availability of levodopa to the brain. However, this effect can be negated in the presence of a DDC inhibitor, which potentiates plasma levodopa level. A single nucleotide polymorphism at the nucleotide 1947 in the catechol-O-methyltransferase (COMT) gene encodes the high (COMT(H)) and low activity (COMT(L)) forms of the enzyme. In this study, we examined the effect of the COMT(L) allele on the clinical response to pyridoxine in Parkinson's disease (PD) patients. PD patients who were on stable and optimized dose of levodopa were included in this study. Their mean motor and activities of living score improved after high dose pyridoxine (P = 0.09, P = 0.04), and worsened after a washout period (P = 0.005, P = 0.001). Using a multivariate model, the presence of the COMT(L) allele predicted response to pyridoxine, with the best outcome observed in COMT(L/L) homozygotes. Our observational study suggests that the status the functional COMT(L) variant may be potentially useful to select PD patients for high dose pyridoxine therapy.

Behind the facial twitch: depressive symptoms in hemifacial spasm.

BACKGROUND: Depression impairs psychosocial and occupational functioning and contributes to significant morbidity and mortality. Hemifacial spasm (HFS) causes social embarrassment and visual and verbal disability. OBJECTIVE: We examined; (1) the prevalence and predictive factors of depressive symptoms (Becks Depression Inventory (BDI) and clinical assessment) in HFS and (2) the sensitivity and specificity of BDI as a screening and diagnostic tool in HFS. METHODS: A large cohort of HFS patients in a movement disorders clinic was clinically evaluated and the BDI self-administered by patients. Univariate analysis and multivariate logistic regression were undertaken to investigate the effect of age, gender, body-mass index, duration and severity of HFS on the outcome of BDI score. ROC (receiver operating characteristics) analysis was utilized to evaluate the sensitivity and specificity and discriminative property of the scale. RESULTS: There were 90 HFS patients with a mean age of 54.4+11.1 (35-79) years, comprising of 58.9% women and with a mean severity HFS score of 2.9+0.8 (range 1-4). The mean BDI score was higher in depressed HFS than in non-depressed HFS (19.7+6.7 vs 4.2+4.9, p<0.0001). Female gender and a younger age were risk factors (p=0.07). In the multivariate analysis, the severity of HFS was an independent predictor of BDI scores (p<0.0001). The AUC was 97.1% suggesting excellent discriminative property of BDI. For cut-off score of 12/13, the sensitivity was 93.3%, specificity 94.7%, Positive Predictive Value 77.8% and Negative Predictive Value 98.6%. CONCLUSIONS: The prevalence of depressive disorder in HFS was 16.7%, with younger women at greater risk. The severity of HFS was positively correlated with the severity of depressive symptoms. The BDI can be a complimentary screening and/or diagnostic instrument for depressive disorder in HFS. Early diagnosis of at-risk patients will prevent unnecessary morbidity and mortality.

Botulinum toxin improves quality of life in hemifacial spasm: validation of a questionnaire (HFS-30).

BACKGROUND: Hemifacial spasm (HFS) can be disabling and affect quality of life. There is a lack of a validated scale for evaluating botulinum toxin (BTX) response in HFS. OBJECTIVE: We examined the validity and reliability of a self-rating health-related quality of life (HRQOL) questionnaire (HFS-30) in HFS and investigated the correlation of this questionnaire with the neurologists' assessment of severity of HFS and response to botulinum toxin (BTX) treatment. METHODS: HFS patients were asked to answer a total of 30 self-rating questions divided into seven subscales: Mobility; Activities of Daily Living (ADL); Emotional Well-being; Stigma; Social support; Cognition; and Communication. All of the items were scored on a 5-point scales ranging from 0 ("never") to 4 ("always"). They were also asked to assess their response to the BTX treatment based on a similar questionnaire at 6-8 weeks after BTX. The validity, reliability and sensitivity of the questionnaire were analyzed statistically. RESULTS: There were 80 HFS patients with mean age of 56.3+/-11.1 (S.D.) years (range 35 to 81), consisting of 54 (67.5%) females, 26 (32.5%) males. The intraclass correlation coefficient (ICC) and Cronbach's alpha were more than 0.7 for the majority of the items and subscales, respectively. There was a good positive correlation of severity of HFS with the subscale scores. Regression analysis of physicians' assessment of response to BTX on change in scores from baseline as rated by patients demonstrated a significant correlation. CONCLUSIONS: We demonstrated validity, reliability and sensitivity of the HFS-30 questionnaire. BTX improves quality of life in HFS.

Dopamine D2 receptor TaqIA and TaqIB polymorphisms in Parkinson's disease.

In a case control study, we examined the association of DRD2 Taq1A and Taq1B polymorphisms and risk of PD, and evaluated the strength of linkage disequilibrium of the polymorphisms. The Taq1A and Taq1B polymorphisms were in strong linkage disequilibrium. There was, however, no significant association of the two polymorphisms with PD.

Alpha synuclein promoter and risk of Parkinson's disease: microsatellite and allelic size variability.

Polymorphism of the alpha synuclein promoter region (non-amyloid component of plaques (NACP)-Rep1) is associated with an increased risk of Parkinson's disease (PD) in three separate studies. We studied NACP-Rep1 polymorphism in two independent case control studies in our population. In study one, 104 PD and 104 age, gender and race matched controls; and in study two, 102 PD and 102 age, gender and race matched controls were examined separately. The results of both studies were analyzed independent of one another. We found three polymorphic alleles (designated 0, 1, 2). In study one, the frequency of allele 2 was significantly higher in PD patients as compared to healthy controls (0.37 versus 0.23, P=0.01, X(2)=9.98). In study two, the frequency of allele 2 was similar between PD and controls (0.31 versus 0.33, P=1.00, X(2)=0.30). There was a non-significant higher allele 2 frequency in PD when both studies were analyzed together (0.34 versus 0.28, P=0.20, X(2)=3.4). No significant differences of the various genotypes between PD and controls were found. However there were differences of the mixed dinucleotide repeats sequences for similar homozygous genotypes. Variability of the microsatellite region and potential interacting factors that could affect alpha synuclein gene transcription should be further examined.