Luis Ruano

The Global Epidemiology of Hereditary Ataxia and Spastic Paraplegia: A Systematic Review of Prevalence Studies

Background: Hereditary cerebellar ataxias (HCA) and hereditary spastic paraplegias (HSP) are two groups of neurodegenerative disorders that usually present with progressive gait impairment, often leading to permanent disability. Advances in genetic research in the last decades have improved their diagnosis and brought new possibilities for prevention and future treatments. Still, there is great uncertainty regarding their global epidemiology. Summary: Our objective was to assess the global distribution and prevalence of HCA and HSP by a systematic review and meta-analysis of prevalence studies. The MEDLINE, ISI Web of Science and Scopus databases were searched (1983-2013) for studies performed in well-defined populations and geographical regions. Two independent reviewers assessed the studies and extracted data and predefined methodological parameters. Overall, 22 studies were included, reporting on 14,539 patients from 16 countries. Multisource population-based studies yielded higher prevalence values than studies based primarily on hospitals or genetic centres. The prevalence range of dominant HCA was 0.0-5.6/105, with an average of 2.7/105 (1.5-4.0/105). Spinocerebellar ataxia type 3 (SCA3)/Machado-Joseph disease was the most common dominant ataxia, followed by SCA2 and SCA6. The autosomal recessive (AR) HCA (AR-HCA) prevalence range was 0.0-7.2/105, the average being 3.3/105 (1.8-4.9/105). Friedreich ataxia was the most frequent AR-HCA, followed by ataxia with oculomotor apraxia or ataxia-telangiectasia. The prevalence of autosomal dominant (AD) HSP (AD-HSP) ranged from 0.5 to 5.5/105 and that of AR-HSP from 0.0 to 5.3/105, with pooled averages of 1.8/105 (95% CI: 1.0-2.7/105) and 1.8/105 (95% CI: 1.0-2.6/105), respectively. The most common AD-HSP form in every population was spastic paraplegia, autosomal dominant, type 4 (SPG4), followed by SPG3A, while SPG11 was the most frequent AR-HSP, followed by SPG15. In population-based studies, the number of families without genetic diagnosis after systematic testing ranged from 33 to 92% in the AD-HCA group, and was 40-46% in the AR-HCA, 45-67% in the AD-HSP and 71-82% in the AR-HSP groups. Key Messages: Highly variable prevalence values for HCA and HSP are reported across the world. This variation reflects the different genetic make-up of the populations, but also methodological heterogeneity. Large areas of the world remain without prevalence studies. From the available data, we estimated that around 1:10,000 people are affected by HCA or HSP. In spite of advances in genetic research, most families in population-based series remain without identified genetic mutation after extensive testing.

Hereditary ataxia and spastic paraplegia in Portugal: a population-based prevalence study.

IMPORTANCE Epidemiological data on hereditary cerebellar ataxia (HCA) and hereditary spastic paraplegia (HSP) are scarce. OBJECTIVE To present the prevalence and distribution of HCA and HSP in Portugal. DESIGN AND SETTING Population-based, nationwide, systematic survey, from January 1, 1994, through April 15, 2004, in Portugal. PARTICIPANTS Multiple sources of information were used (review of clinical files, active collaboration of neurologists and geneticists, and investigation of affected families), but the main source was active collaboration of general practitioners. Patients were examined by the same team of neurologists, using homogeneous inclusion criteria. The clinical data were registered, and all families were genetically tested. RESULTS Overall, 1336 patients from a population of 10,322 million were diagnosed as having HCA or HSP, a prevalence of 12.9 per 100,000 population. Hereditary cerebellar ataxia was more prevalent (prevalence, 8.9 per 100,000 population; 5.6 for dominant and 3.3 for recessive ataxias) than HSP (prevalence, 4.1 per 100,000 population; 2.4 for dominant and 1.6 for recessive). Machado-Joseph disease (spinocerebellar ataxia type 3) (prevalence, 3.1 per 100,000 population), Friedreich ataxia (prevalence, 1.0 per 100,000 population), and ataxia with oculomotor apraxia (prevalence, 0.4 per 100,000 population) were the most frequent HCAs. Spastic paraplegia types 4 (prevalence, 0.91 per 100,000 population), 3 (prevalence, 0.14 per 100,000 population), and 11 (prevalence, 0.26 per 100,000 population) were the most prevalent HSPs. CONCLUSIONS AND RELEVANCE This population-based survey covered all the Portuguese territory and mobilized most general practitioners and health centers. To our best knowledge, this survey was the largest ever performed for HCA and HSP. Prevalence of autosomal dominant ataxias was high, particularly for Machado-Joseph disease (spinocerebellar ataxia type 3). The genetic cause has not been identified in 39.7% of the patients studied.

Age and disability drive cognitive impairment in multiple sclerosis across disease subtypes

Background: There is limited and inconsistent information on the clinical determinants of cognitive impairment (CI) in multiple sclerosis (MS). Objective: The aim of this study was to compare the prevalence and profile of CI across MS disease subtypes and assess its clinical determinants. Methods: Cognitive performance was assessed through the Brief Repeatable Battery and the Stroop test in consecutive patients with MS referred to six Italian centers. CI was defined as impairment in ⩾ 2 cognitive domains. Results: A total of 1040 patients were included, 167 with clinically isolated syndrome (CIS), 759 with relapsing remitting (RR), 74 with secondary progressive (SP), and 40 with primary progressive (PP) disease course. The overall prevalence of CI was 46.3%; 34.5% in CIS, 44.5% in RR, 79.4% in SP, and 91.3% in PP. The severity of impairment and the number of involved domains were significantly higher in SP and primary progressive multiple sclerosis (PPMS) than in CIS and RR. In multivariable logistic regression analysis, the presence of CI was significantly associated with higher Expanded Disability Status Scale (EDSS) and older age. Conclusion: CI is present in all MS subtypes since the clinical onset and its frequency is increased in the progressive forms, but these differences seem to be more associated with patient age and physical disability than to disease subtype per se.

Autosomal Dominant Spastic Paraplegias: A Review of 89 Families Resulting From a Portuguese Survey

IMPORTANCE Hereditary spastic paraplegias (HSPs) are a group of diseases caused by corticospinal tract degeneration. Mutations in 3 genes (SPG4, SPG3, and SPG31) are said to be the cause in half of the autosomal dominant HSPs (AD-HSPs). This study is a systematic review of families with HSP resulting from a population-based survey. Novel genotype-phenotype correlations were established. OBJECTIVE To describe the clinical, genetic, and epidemiological features of Portuguese AD-HSP families. DESIGN Retrospective medical record review. SETTING A population-based systematic survey of hereditary ataxias and spastic paraplegias conducted in Portugal from 1993 to 2004. PARTICIPANTS Families with AD-HSP. MAIN OUTCOME MEASURE Mutation detection in the most prevalent genes. RESULTS We identified 239 patients belonging to 89 AD-HSP families. The prevalence was 2.4 in 100 000. Thirty-one distinct mutations (26 in SPG4, 4 in SPG3, and 1 in SPG31) segregated in 41% of the families (33.7%, 6.2%, and 1.2% had SPG4, SPG3 and SPG31 mutations, respectively). Seven of the SPG4 mutations were novel, and 7% of all SPG4 mutations were deletions. When disease onset was before the first decade, 31% had SPG4 mutations and 27% had SPG3 mutations. In patients with SPG4 mutations, those with large deletions had the earliest disease onset, followed by those with missense, frameshift, nonsense, and alternative-splicing mutations. Rate of disease progression was not significantly different among patients with SPG3 and SPG4 mutations in a multivariate analysis. For patients with SPG4 mutations, disease progression was worst in patients with later-onset disease. CONCLUSIONS AND RELEVANCE The prevalence of AD-HSP and frequency of SPG3 and SPG4 mutations in the current study were similar to what has been described in other studies except that the frequency of SPG4 deletions was lower. In contrast, the frequency of SPG31 mutations in the current study was rare compared with other studies. The most interesting aspects of this study are that even in patients with early-onset disease the probability of finding a SPG4 mutation was higher than for patients with SPG3 mutations; there was no difference in disease progression with genotype but an association with the age at onset; 7 new SPG4 mutations were identified; and for the first time, to our knowledge, the nature of the SPG4 mutations was found to predict the age at onset.

Web-based cognitive training: patient adherence and intensity of treatment in an outpatient memory clinic.

Background Cognitive training has been playing an increasing role in the treatment of patients with cognitive deficits. This type of intervention, namely its intensity, can be optimized by incorporating information technology-based systems. Objective The intent of the study was to determine the treatment intensity and patient adherence to home-based cognitive training strategies (Web-based cognitive training). Methods A cohort of 45 patients with neurologic and psychiatric diseases attending an outpatient memory clinic (average age 50.7 years, SD 17.0; average education 7.8 years, SD 4.9) was followed over 18 months. Participants were challenged to use a Web-based cognitive training system, “COGWEB”, on a daily basis, and fulfilled at least four weeks of training supervised remotely. Additionally, 11 patients attended face-to-face sessions. Results The average duration of continuous cognitive training was 18.8 weeks (SD 18.9). Each patient performed on average 363.5 minutes/week (SD 136.6). At 6-month follow-up, 82.8% complied with their treatment plan. The average proportion of complete weeks was 0.75 (SD 0.22). Patients with dementia trained more intensively (444.6 minutes/week), followed by patients with static brain lesion (414.5 minutes/week; P=.01). The group that held face-to-face sessions performed more training overall (481.4 vs 366.9 minutes/week), achieving a stronger expression and statistical significance in the last week of training (652.6 versus 354.9 minutes/week, P=.027). Conclusions Overall, the weekly training intensity was high. Patients with dementia and static lesions performed more cognitive training. Face-to-face sessions were associated with higher intensities. The combination of classical methods with information technology systems seems to ensure greater training intensity.

Development of a self-administered web-based test for longitudinal cognitive assessment.

Sequential testing with brief cognitive tools has been recommended to improve cognitive screening and monitoring, however the few available tools still depend on an external evaluator and periodic visits. We developed a self-administered computerized test intended for longitudinal cognitive testing (Brain on Track). The test can be performed from a home computer and is composed of several subtests, expected to evaluate different cognitive domains, all including random elements to minimize learning effects. An initial (A) and a refined version of the test (B) were applied to patients with mild cognitive impairment or early dementia (n = 88) and age and education-matched controls. A subsample of a population-based cohort (n = 113) performed the test at home every three months to evaluate test-retest reliability. The test’s final version Cronbach’s alpha was 0.90, test scores were significantly different between patients and controls (p = 0.001), the area under the receiver operating characteristic curve was 0.75 and the smallest real difference (43.04) was lower than the clinical relevant difference (56.82). In the test-retest reliability analysis 9/10 subtests showed two-way mixed single intraclass consistency correlation coefficient >0.70. These results imply good internal consistency, discriminative ability and reliability when performed at home, encouraging further longitudinal clinical and population-based studies.

Patients with paediatric-onset multiple sclerosis are at higher risk of cognitive impairment in adulthood: An Italian collaborative study

Background: Patients with paediatric-onset multiple sclerosis (POMS) could be at an increased risk for cognitive impairment (CI), given the potential harmful effects of disease activity in neurodevelopment. However, there is scarce information on their long-term cognitive outcomes. Objective: To compare the prevalence and profile of CI between adults with a history of POMS and those with classic, adult-onset multiple sclerosis (AOMS). Methods: Cognitive performance was assessed through the Brief Repeatable Battery (BRB) and the Stroop Test in consecutive patients referred to six Italian MS centres. CI was defined as impairment in ⩾2 cognitive domains. Results: In all, 119 patients with POMS and 712 with AOMS were included in this analysis. The prevalence of CI was 48.0% in AOMS, 44.5% in POMS; with similar neuropsychological profile between the two groups. However, when adjusting for current age, we found a significantly increased risk for CI (odds ratio (OR) = 1.71; p = 0.02) and for impairment in information processing speed (OR = 1.86; p < 0.01) in patients with POMS. A higher Expanded Disability Status Scale (EDSS) was also identified in POMS (p = 0.03) compared with AOMS patients. Conclusion: Patients with a history of POMS appear to be at higher risk of physical and cognitive disability than AOMS patients, after correcting for age effects, with particular involvement of information processing speed.

Ischemic vagus nuclei lesions and hyperglycemia: a study in 26 patients with lateral medullary infarction and matched controls.

Background: Hyperglycemia is common after stroke in diabetic and nondiabetic patients. Furthermore, it has been associated with infarct expansion, worse functional outcomes and higher mortality. In a previous study, infarction of the insular region was related to higher poststroke glucose levels than infarcts in other cortical areas. Experimental studies in animal models suggested that the lower brainstem nuclei of the vagus nerve modulate insulin secretion. These nuclei are usually affected in lateral medullary infarction (LMI). We evaluated whether patients with lateral medullary stroke have worse poststroke glycemic control than other stroke patients. Methods: A hospital-based stroke registry was used to identify 26 patients from the years 2000 to 2010 who fulfilled the following inclusion criteria: (1) a first-ever stroke; (2) neurological deficits compatible with LMI; (3) MRI confirmation of an ischemic lesion of the lateral medulla involving the vagus nerve nuclei, and (4) no simultaneous infarcts. Patients were excluded if they were admitted to the hospital more than 24 h after stroke onset or died in the first 24 h after hospital admission. A control group of other stroke patients was randomly selected from the same stroke registry and over the same time period, matching for the age and gender of the LMI group. The average glycemia was compared between the two groups using a linear regression model adjusted for confounders. Glycated hemoglobin at admission was used to estimate prestroke glycemic control. Prestroke glycemic averages were then compared with poststroke glycemia for the two groups using the Wilcoxon signed test for related samples. Results: The average glycemia of the LMI patients in the first 24 h after stroke was 9.4 mmol/l (SD 3.2), and from 24 to 72 h it was 7.6 mmol/l (SD 2.8). In the comparison group, these values were 7.7 (SD 2.8) and 7.1 mmol/l (SD 2.7), respectively. As expected, diabetic patients had a significantly higher glycemia than nondiabetic patients (p < 0.0001). The adjusted linear regression model showed the average glycemia differences to be significant for the first 24 h (p = 0.001; R2 = 55.6%) but not for the 24– 72 h period. The frequency of previous diabetes mellitus was similar in both groups. As compared to prestroke glycemic estimates, glycemia in lateral medullary stroke patients increased significantly more than in controls during the first 24 h after stroke (p = 0.01), but again there were no significant differences for the 24–72 h period. Conclusions: This study suggests that ischemic lesions of the vagus nerve nuclei are associated with worse early poststroke glycemic control than stroke in other locations. Confirmation of this hypothesis and the long-term implications of glucose control impairment warrant further prospective studies.

Superficial Siderosis and Anticoagulation Therapy: Different Presentations, Different Outcomes

Superficial siderosis is a potentially manageable neurodegenerative disorder, caused by chronic subarachnoid haemorrhage and iron deposition along the central nervous system surfaces. Association with oral anticoagulant therapy is well known, but its definite role as a causative agent is yet to be clarified. Two Caucasian women, both under long-term oral anticoagulation: a 74 year old woman with slowly progressive hearing loss and mild cerebellar ataxia; a 72 year old woman suffering from behavioural changes, rapidly progressive cognitive decline and latter developing paraparesis. Magnetic resonance imaging showed striking hypointensities along the surfaces of cerebellum, brainstem, frontotemporal cortices, spinal cord, and lumbar arachnoid therefore suggesting superficial siderosis. No specific bleeding source was found in any of the patients. Anticoagulation could not be stopped in the first patient due to a mechanic valve and slowly progressive worsening occurred. In contrast, for the second patient anticoagulation withdrawal was feasible and marked motor and cognitive improvement ensued. Superficial siderosis is associated with unvarying progression, mostly when no direct source of bleeding is identified. Nonetheless, we verified striking motor and cognitive improvement after anticoagulants withdrawal in one of the patients. This may reinforce the need to consider such modifiable factor in future patient management.

Motor task performance under vibratory feedback early poststroke: single center, randomized, cross-over, controled clinical trial

Stroke rehabilitation is far from meeting patient needs in terms of timing, intensity and quality. This study evaluates the efficacy and safety of an innovative technological tool, combining 3D motion analysis with targeted vibratory feedback, on upper-limb task performance early poststroke (<4 weeks). The study design was a two-sequence, two-period, randomized, crossover trial (NCT01967290) in 44 patients with upper-limb motor deficit (non-plegic) after medial cerebral artery ischemia. Participants were randomly assigned to receive either the experimental session (repetitive motor task under vibratory feedback and 3D motor characterization) or the active comparator (3D motor characterization only). The primary outcome was the number of correct movements per minute on a hand-to-mouth task measured independently. Vibratory feedback was able to modulate motor training, increasing the number of correct movements by an average of 7.2/min (95%CI [4.9;9.4]; P < 0.001) and reducing the probability of performing an error from 1:3 to 1:9. This strategy may improve the efficacy of training on motor re-learning processes after stroke, and its clinical relevance deserves further study in longer duration trials.