TDP-43 pathology occurs infrequently in multiple system atrophy

AIMS AND METHODS

The α-synucleinopathy multiple system atrophy (MSA) and diseases defined by pathological 43-kDa transactive response DNA-binding protein (TDP-43) or fused in sarcoma (FUS) aggregates such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration show overlapping clinico-pathological features. Consequently, we examined MSA for evidence of TDP-43 or FUS pathology utilizing immunohistochemical studies in autopsy material from 29 MSA patients.

RESULTS

TDP-43 pathology was generally rare, and there were no FUS lesions. The TDP-43 lesions were located predominantly in medio-temporal lobe and subcortical brain areas and were comprised mainly of dystrophic processes and perivascular (and subpial) lesions.

CONCLUSIONS

The multisystem clinical symptoms and signs of MSA, and in particular the neurobehavioural/cognitive and pyramidal features, appear not to result from concomitant TDP-43 or FUS pathology, but rather from widespread white matter α-synuclein positive glial cytoplasmic inclusions and neurodegeneration in keeping with a primary α-synuclein-mediated oligodendrogliopathy. The gliodegenerative disease MSA evidently results from different pathogenetic mechanisms than neurodegenerative diseases linked to pathological TDP-43.

A phase 2 randomized trial of ELND005, scyllo-inositol, in mild to moderate Alzheimer disease

OBJECTIVE

This randomized, double-blind, placebo-controlled, dose-ranging phase 2 study explored safety, efficacy, and biomarker effects of ELND005 (an oral amyloid anti-aggregation agent) in mild to moderate Alzheimer disease (AD).

METHODS

A total of 353 patients were randomized to ELND005 (250, 1,000, or 2,000 mg) or placebo twice daily for 78 weeks. Coprimary endpoints were the Neuropsychological Test Battery (NTB) and Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scale. The primary analysis compared 250 mg (n =84) to placebo (n =82) after an imbalance of infections and deaths led to early discontinuation of the 2 higher dose groups.

RESULTS

The 250 mg dose demonstrated acceptable safety. The primary efficacy analysis at 78 weeks revealed no significant differences between the treatment groups on the NTB or ADCS-ADL. Brain ventricular volume showed a small but significant increase in the overall 250 mg group (p =0.049). At the 250 mg dose, scyllo-inositol concentrations increased in CSF and brain and CSF Aβx-42 was decreased significantly compared to placebo (p =0.009).

CONCLUSIONS

Primary clinical efficacy outcomes were not significant. The safety and CSF biomarker results will guide selection of the optimal dose for future studies, which will target earlier stages of AD.

CLASSIFICATION OF EVIDENCE

Due to the small sample sizes, this Class II trial provides insufficient evidence to support or refute a benefit of ELND005.

Cerebral cortical and subcortical cholinergic deficits in parkinsonian syndromes

OBJECTIVES

Cholinergic projections to cerebral cortical and subcortical regions are decreased in Parkinson disease (PD), but not evaluated in the parkinsonian syndromes of multiple system atrophy (MSA-P) and progressive supranuclear palsy (PSP). We studied cholinergic innervation in these disorders as compared to age-appropriate normal control subjects.

METHODS

We used PET with [(11)C]PMP to measure acetylcholinesterase (AChE) activity in multiple cerebral cortical and subcortical regions. We studied 22 normal controls, 12 patients with PD, 13 patients with MSA-P, and 4 patients with PSP.

RESULTS

We found significantly decreased AChE activity in most cerebral cortical regions in PD and MSA-P, and a similar but nonsignificant decrease in PSP. No differences were found between PD and MSA-P. Significantly decreased AChE activity was found in PD in striatum, cerebellum, and thalamus, with a marginally significant decrease in mesencephalon and no change in pons. Significantly greater declines in AChE activity in all subcortical regions were seen in MSA-P and PSP vs in PD. Decreased AChE activity in brainstem and cerebellum of all 3 disorders correlated with disturbances of balance and gait.

CONCLUSIONS

Cerebral cortical cholinergic activity is decreased to a similar level in Parkinson disease (PD), parkinsonian syndromes of multiple system atrophy (MSA-P), and progressive supranuclear palsy (PSP) as compared to normal controls. Subcortical cholinergic activity is significantly more decreased in MSA-P and PSP than in PD. The more substantial decrease reflects greater impairment in the pontine cholinergic group, which is important in motor activity, particularly gait. These differences may account for the greater gait disturbances in the early stages of MSA-P and PSP than in PD.

A phase 2 multiple ascending dose trial of bapineuzumab in mild to moderate Alzheimer disease

BACKGROUND

Bapineuzumab, a humanized anti-amyloid-beta (Abeta) monoclonal antibody for the potential treatment of Alzheimer disease (AD), was evaluated in a multiple ascending dose, safety, and efficacy study in mild to moderate AD.

METHODS

The study enrolled 234 patients, randomly assigned to IV bapineuzumab or placebo in 4 dose cohorts (0.15, 0.5, 1.0, or 2.0 mg/kg). Patients received 6 infusions, 13 weeks apart, with final assessments at week 78. The prespecified primary efficacy analysis in the modified intent-to-treat population assumed linear decline and compared treatment differences within dose cohorts on the Alzheimer's Disease Assessment Scale-Cognitive and Disability Assessment for Dementia. Exploratory analyses combined dose cohorts and did not assume a specific pattern of decline.

RESULTS

No significant differences were found in the primary efficacy analysis. Exploratory analyses showed potential treatment differences (p < 0.05, unadjusted for multiple comparisons) on cognitive and functional endpoints in study "completers" and APOE epsilon4 noncarriers. Reversible vasogenic edema, detected on brain MRI in 12/124 (9.7%) bapineuzumab-treated patients, was more frequent in higher dose groups and APOE epsilon4 carriers. Six vasogenic edema patients were asymptomatic; 6 experienced transient symptoms.

CONCLUSIONS

Primary efficacy outcomes in this phase 2 trial were not significant. Potential treatment differences in the exploratory analyses support further investigation of bapineuzumab in phase 3 with special attention to APOE epsilon4 carrier status.

CLASSIFICATION OF EVIDENCE

Due to varying doses and a lack of statistical precision, this Class II ascending dose trial provides insufficient evidence to support or refute a benefit of bapineuzumab.

Immigration to the USA and risk for mood and anxiety disorders: variation by origin and age at immigration

BACKGROUND

Risk for mood and anxiety disorders associated with US-nativity may vary across immigrant groups.

METHOD

Using data from the National Epidemiological Study of Alcohol and Related Conditions (NESARC), we examined the association of lifetime risk for mood and anxiety disorders with US-nativity and age at immigration across seven subgroups of the US population defined by country or region of ancestral origin: Mexico, Puerto-Rico, Cuba, Central and South America, Western Europe, Eastern Europe, and Africa and the Caribbean. Discrete time survival models were used to compare lifetime risk between the US-born, immigrants who arrived in the USA prior to the age of 13 years and immigrants who arrived in the USA at the age of 13 years or older.

RESULTS

The association of risk for mood and anxiety disorders with US-nativity varies significantly across ancestral origin groups (p<0.001). Among people from Mexico, Eastern Europe, and Africa or the Caribbean, risk for disorders is lower relative to the US-born among immigrants who arrived at the age of 13 years or higher (odds ratios in the range 0.34-0.49) but not among immigrants who arrived prior to the age of 13 years. There is no association between US-nativity and risk for disorder among people from Western Europe and Puerto Rico.

CONCLUSIONS

Low risk among immigrants relative to the US-born is limited to groups among whom risk for mood and anxiety disorder is low in immigrants who spent their pre-adolescent years outside of the USA.

Second consensus statement on the diagnosis of multiple system atrophy

BACKGROUND

A consensus conference on multiple system atrophy (MSA) in 1998 established criteria for diagnosis that have been accepted widely. Since then, clinical, laboratory, neuropathologic, and imaging studies have advanced the field, requiring a fresh evaluation of diagnostic criteria. We held a second consensus conference in 2007 and present the results here.

METHODS

Experts in the clinical, neuropathologic, and imaging aspects of MSA were invited to participate in a 2-day consensus conference. Participants were divided into five groups, consisting of specialists in the parkinsonian, cerebellar, autonomic, neuropathologic, and imaging aspects of the disorder. Each group independently wrote diagnostic criteria for its area of expertise in advance of the meeting. These criteria were discussed and reconciled during the meeting using consensus methodology.

RESULTS

The new criteria retain the diagnostic categories of MSA with predominant parkinsonism and MSA with predominant cerebellar ataxia to designate the predominant motor features and also retain the designations of definite, probable, and possible MSA. Definite MSA requires neuropathologic demonstration of CNS alpha-synuclein-positive glial cytoplasmic inclusions with neurodegenerative changes in striatonigral or olivopontocerebellar structures. Probable MSA requires a sporadic, progressive adult-onset disorder including rigorously defined autonomic failure and poorly levodopa-responsive parkinsonism or cerebellar ataxia. Possible MSA requires a sporadic, progressive adult-onset disease including parkinsonism or cerebellar ataxia and at least one feature suggesting autonomic dysfunction plus one other feature that may be a clinical or a neuroimaging abnormality.

CONCLUSIONS

These new criteria have simplified the previous criteria, have incorporated current knowledge, and are expected to enhance future assessments of the disease.

Systemic lupus erythematosus in men: a retrospective analysis in a Veterans Administration Healthcare System population

Systemic lupus erythematosus (SLE), a connective tissue disease of unknown etiology, is generally considered to occur in women of child-bearing age and to be uncommon among men . Because of the female predominance in most studies, less is known about the disease in men. To begin to better understand lupus in men, we retrospectively analyzed all the SLE patients from all the hospitals in the Department of Veterans Affairs (VA) system, a population that is predominantly male. Between 1987 and 1996, 2614 SLE patients were retrieved from the VA databank; 2144 were male, making this the largest group of male patients with SLE reported in United States of America. Age, racial and geographic distribution, comorbidities, and mortality of the SLE patients are reported. This study suggests that SLE men in this population are older at onset of disease, have different comorbidities, and have a higher mortality at 1 year than women with SLE. These findings suggest that men with SLE have a more complex clinical course than women, although the data do not illuminate whether the comorbidities are due to or coincident with SLE. On the basis of these data, practitioners are reminded to consider SLE in the differential diagnosis for older men and be attentive to the frequent presence of comorbidities such as cardiac ischemia and neoplasms. Because of the identified regional variations in demographics, comorbidities, and mortality, this study suggests the need for future SLE studies to include data from multiple geographic areas.

Lack of effect of rifalazil on ethinyl estradiol pharmacokinetics in healthy postmenopausal women

Rifalazil, a second-generation rifamycin, is being evaluated for the treatment of sexually transmitted disease and gastrointestinal infections. We determined whether rifalazil influences CYP3A4 metabolism by studying the effect of a single oral, 25 mg dose of rifalazil administered to healthy postmenopausal women, on the steady-state pharmacokinetics (PK) of ethinyl estradiol (EE) during administration of Ortho-Novum 1/35 (EE/NET). Noncompartmental PK and sequential statistical analyses were performed to establish if and when subjects achieved steady-state EE plasma concentrations and to determine whether this steady state was altered by rifalazil administration. The geometric mean ratios for the difference between EE alone and following rifalazil for EE Cmax, AUC(0-24) and Cmin were 105.9, 104.4 and 105.0, respectively. The 90% confidence intervals for each ratio fell within 80 - 125% of the reference treatment indicating no significant difference in the PK of EE before or after rifalazil administration. The posterior probabilities for the true treatment differences of Cmax or AUC(0-24) being less than 20% were > 99.99% in both cases. Based on the results of this study, there is no CYP3A4-metabolic interaction between a single oral, 25 mg dose of rifalazil and EE for either induction or inhibition. Consequently, there is minimal threat of contraceptive failure when single doses of rifalazil are administered with EE/NET. A single dose of rifalazil 25 mg was well tolerated when administered concomitantly with a combination oral contraceptive (EE/NET) by healthy postmenopausal females.

The North American Multiple System Atrophy Study Group

The North American Multiple System Atrophy Study Group involves investigators in 12 US medical centers funded by a grant from the National Institutes of Health. The objectives are to examine the environmental and genetic risk factors for MSA; elucidate pathogenic mechanisms underlying the disorder; and refine evaluations used for assessment. During its first year, the group enrolled 87 patients, implemented four cores, and initiated four scientific projects. Most patients among the 87 had parkinsonian features, which frequently began asymmetrically and remained asymmetrical; one-third responded to levodopa and many developed levodopa complications; almost two-thirds of the patients had cerebellar dysfunction, of these 90% had ataxia; urinary incontinence occurred commonly, and sleep disorders affected most. The investigators studied the effects of oxidative and nitrative stress upon the formation of alpha-synuclein inclusions; generated transgenic models of alpha-synuclein accumulation that recapitulate several behavioral and neuropathological features of MSA; and compared the severity of the autonomic features of MSA, Parkinson's disease and dementia with Lewy bodies.

Clinical effects of Abeta immunization (AN1792) in patients with AD in an interrupted trial

BACKGROUND

AN1792 (beta-amyloid [Abeta]1-42) immunization reduces Abeta plaque burden and preserves cognitive function in APP transgenic mice. The authors report the results of a phase IIa immunotherapy trial of AN1792(QS-21) in patients with mild to moderate Alzheimer disease (AD) that was interrupted because of meningoencephalitis in 6% of immunized patients.

METHODS

This randomized, multicenter, placebo-controlled, double-blind trial of IM AN1792 225 microg plus the adjuvant QS-21 50 microg (300 patients) and saline (72 patients) included patients aged 50 to 85 years with probable AD, Mini-Mental State Examination (MMSE) 15 to 26. Injections were planned for months 0, 1, 3, 6, 9, and 12. Safety and tolerability were evaluated, and pilot efficacy (AD Assessment Scale-Cognitive Subscale [ADAS-Cog], MRI, neuropsychological test battery [NTB], CSF tau, and Abeta42) was assessed in anti-AN1792 antibody responder patients (immunoglobulin G titer > or = 1:2,200).

RESULTS

Following reports of meningoencephalitis (overall 18/300 [6%]), immunization was stopped after one (2 patients), two (274 patients), or three (24 patients) injections. Of the 300 AN1792(QS-21)-treated patients, 59 (19.7%) developed the predetermined antibody response. Double-blind assessments were maintained for 12 months. No significant differences were found between antibody responder and placebo groups for ADAS-Cog, Disability Assessment for Dementia, Clinical Dementia Rating, MMSE, or Clinical Global Impression of Change, but analyses of the z-score composite across the NTB revealed differences favoring antibody responders (0.03 +/- 0.37 vs -0.20 +/- 0.45; p = 0.020). In the small subset of subjects who had CSF examinations, CSF tau was decreased in antibody responders (n = 11) vs placebo subjects (n = 10; p < 0.001).

CONCLUSION

Although interrupted, this trial provides an indication that Abeta immunotherapy may be useful in Alzheimer disease.

Functional imaging with positron emission tomography in multiple system atrophy

Although the current guidelines for the clinical diagnosis of multiple system atrophy (MSA) do not require structural or functional brain imaging, investigations utilizing positron emission tomography (PET) have been helpful diagnostically in differentiating between MSA and primary autonomic failure; idiopathic Parkinson's disease; and sporadic olivopontocerebellar atrophy. These investigations have demonstrated different patterns of cerebral glucose utilization and of nigrostriatal projection abnormalities among these disorders and between the cerebellar and parkinsonian forms of MSA. Most of the studies have focused upon patients with well-established disease and none have examined the utility of PET imaging in early stage patients with follow-up of clinical course and autopsy verification to ensure accuracy of diagnosis and to determine the sensitivity and specificity of PET techniques for diagnosis. Recent PET studies have revealed denervation of myocardial post-ganglionic sympathetic neurons in some MSA patients, indicating that this disorder can affect the peripheral autonomic as well as the central nervous system. Investigations utilizing ligands to quantify central nervous system dopaminergic and cholinergic terminals have begun to provide insight into the neurochemical disorders that may underlie two of the sleep disturbances common in MSA, rapid eye movement sleep behavior disorder and obstructive sleep apnea.

Effects of A immunization (AN1792) on MRI measures of cerebral volume in Alzheimer disease

BACKGROUND

Alzheimer disease (AD) is characterized by progressive cerebral atrophy that may be measured using MRI. Reported are MRI findings of a Phase IIa immunotherapy trial in AD prematurely terminated owing to meningoencephalitis in a subset of patients.

OBJECTIVE

To assess cerebral volume changes in patients immunized with AN1792 (beta-amyloid [Abeta] 1 to 42) who were antibody responders (anti-AN1792 IgG titer of > or =1:2,200) compared with placebo patients.

METHODS

This randomized, multicenter, placebo-controlled, double-blind trial of AN1792 225 mug plus QS-21 50 mug included 372 patients with probable AD. Patients received one to three injections of AN1792/QS-21 or saline and were assessed for 12 months. Volumetric MRI was performed pre dose and at month 12 or early termination. Brain, ventricular, and hippocampal volume changes were measured from registered scan pairs.

RESULTS

Two hundred eighty-eight patients had paired scans (mean interval 10.9 months). Antibody responders (n = 45) had greater brain volume decrease (3.12 +/- 1.98 vs 2.04 +/- 1.74%; p = 0.007), greater ventricular enlargement as a percentage of baseline brain volume (1.10 +/- 0.75 vs 0.48 +/- 0.40%; p < 0.001), and a nonsignificant greater hippocampal volume decrease (3.78 +/- 2.63 vs 2.86 +/- 3.19%; p = 0.124) than placebo patients (n = 57). Increased losses in brain volume were not reflected in worsening cognitive performance; a composite z score across a Neuropsychological Test Battery showed differences favoring antibody responders over placebo (0.03 +/- 0.39 vs -0.24 +/- 0.45; p = 0.008).

CONCLUSIONS

A dissociation between brain volume loss and cognitive function was observed in AN1792/QS-21 antibody responders. The reasons for this remain unclear but include the possibility that volume changes were due to amyloid removal and associated cerebral fluid shifts.

REM sleep behavior disorder is related to striatal monoaminergic deficit in MSA

OBJECTIVE

To explore the neurochemical basis of REM sleep behavior disorder (RBD) in multiple-system atrophy (MSA).

METHODS

In 13 patients with probable MSA, nocturnal, laboratory-based polysomnography was used to rate the severity of REM atonia loss by the percentage of REM sleep with tonically increased electromyographic (EMG) activity and the percentage of REM sleep with phasic EMG bursts. PET with (+)-[11C]dihydrotetrabenazine ([11C]DTBZ) was employed to measure the density of striatal monoaminergic terminals and SPECT with (-)-5-[123I]iodobenzovesamicol ([123I]IBVM) to measure the density of 123I]IBVM.

RESULTS

Age and gender distributions were similar in patient and normal control groups. The MSA subjects showed decreased mean [11C]DTBZ binding in the striatum (p < 0.0001) and decreased [123I]IBVM binding in the thalamus (p < 0.001). Moreover, in the MSA group, striatal [11C]DTBZ binding was inversely correlated with the severity of REM atonia loss (p = 0.003). Thalamic [123I]IBVM binding, however, was not correlated to the severity of REM atonia loss.

CONCLUSION

Decreased nigrostriatal dopaminergic projections may contribute to RBD in MSA.

Obstructive sleep apnea is related to a thalamic cholinergic deficit in MSA

OBJECTIVE

To explore the neurochemical basis of obstructive sleep apnea (OSA) in multiple-system atrophy (MSA).

METHODS

In 13 patients with probable MSA, nocturnal, laboratory-based polysomnography was used to rate the severity of OSA using the apnea-hypopnea index during sleep. SPECT with (-)-5-[123I]iodobenzovesamicol ([123I]IBVM) was utilized to measure the density of thalamic cholinergic terminals, which project from the brainstem pedunculopontine and laterodorsal tegmental nuclei. PET with (+)-[11C]dihydrotetrabenazine ([11C]DTBZ) was also used to measure the density of striatal monoaminergic terminals, which project from the brainstem. Findings in the patient group were compared with data from 12 normal control subjects scanned utilizing [123I]IBVM and 15 normal control subjects utilizing [11C]DTBZ.

RESULTS

Age and gender distributions were similar in patient and control groups. The MSA subjects showed decreased [123I]IBVM binding in the thalamus (p < 0.001) and decreased mean [11C]DTBZ binding in the striatum (p < 0.0001) in comparison with the control subjects. In the MSA group, thalamic [123I]IBVM binding was inversely correlated with the severity of OSA (p = 0.011). Striatal [11C]DTBZ binding was not correlated with the severity of OSA (p = 0.19).

CONCLUSION

Decreased pontine cholinergic projections may contribute to OSA in MSA.

Subacute meningoencephalitis in a subset of patients with AD after Abeta42 immunization

BACKGROUND

AD is characterized by cerebral deposition of beta-amyloid plaques with amyloid beta-peptide (Abeta) 42 as the major peptide constituent, along with neurofibrillary tangles and neuronal loss. In transgenic mice, active immunization against Abeta42 removes these plaques and improves cognitive function. A Phase I study in AD patients demonstrated good safety and tolerability of multiple injections of aggregated Abeta42 (AN1792) with QS-21 as adjuvant.

METHODS

Three hundred seventy-two patients with mild to moderate AD were randomized to receive IM injections of AN1792 or placebo (4:1) at baseline and at months 1, 3, 6, 9, and 12 in a multicenter Phase II safety, tolerability, and pilot efficacy study. Dosing was terminated after four early reports of meningoencephalitis, but follow-up continued. The study remains blinded, and further results will be reported after its termination.

RESULTS

Symptoms and laboratory findings consistent with meningoencephalitis occurred in 18 of 298 (6%) patients treated with AN1792 compared with 0 of 74 on placebo (p = 0.020). Sixteen of the 18 had received two doses, one had received one dose, and one had received three doses of the study drug before symptoms occurred. The median latency from the first and last injections to symptoms was 75 and 40 days. No case occurred later than 6 months after the first immunization. Anti-Abeta42 antibody titers were not correlated with the occurrence or severity of symptoms or relapses. Twelve patients recovered to or close to baseline within weeks, whereas six remain with disabling cognitive or neurologic sequelae. All 18 patients remain alive to date (December 31, 2002), 6 months to >1 year after symptom onset.

CONCLUSIONS

Postvaccination meningoencephalitis occurred without clear relation to serum anti-Abeta42 antibody titers. Potential mechanisms such as T-cell and microglial activation may be responsible and are under consideration to develop a safer anti-Abeta immunotherapy for AD.

Joint position sense and vibration sense: anatomical organisation and assessment

Clinical examination of joint position sense and vibration sense can provide important information concerning specific cutaneous sensory receptors, peripheral nerves, dorsal roots, and central nervous system pathways and should be included as a regular component of the neurological examination. Although these sensory modalities share a spinal cord and brainstem pathway, they arise in different receptors and terminate in separate distributions within the thalamus and cerebral cortex. Consequently, both modalities should be tested as part of the neurological examination. Clinical testing of these modalities requires simultaneous stimulation of tactile receptors; hence this review will include information about the receptors and pathways responsible for tactile sensation.

Patterns of neuropsychological performance in multiple system atrophy compared to sporadic and hereditary olivopontocerebellar atrophy

Although neuropsychological symptoms are associated with multiple system atrophy (MSA), sporadic olivopontocerebellar atrophy (sOPCA), and dominantly inherited olivopontocerebellar atrophy (dOPCA), the differences between these groups have not been explored. We compared 28 MSA patients on psychiatric rating scales and neuropsychological measures to 67 sOPCA patients, 42 dOPCA patients, and 30 normal controls. Patients with dOPCA, sOPCA, and MSA all exhibited significant deficits on motor-related tasks, as well as relatively mild deficits in cognitive functioning. Patients with MSA had greater neuropsychological dysfunction, particularly in memory and other "higher order" cognitive processes, than patients with either sOPCA or dOPCA.

Biochemical changes in multiple system atrophy detected with positron emission tomography

Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder manifested by parkinsonism and dysfunction of autonomic, cerebellar, urinary, and pyramidal systems. The most frequent presentation is with a combination of parkinsonism and autonomic dysfunction, but cerebellar ataxia with autonomic failure occurs frequently as well. Striatonigral degeneration (SND) and sporadic olivopontocerebellar atrophy (sOPCA) can progress to include autonomic failure and thus may be forms of MSA, but it is not known whether all such cases progress to MSA. Utilizing positron emission tomography (PET) with various ligands, my colleagues and I have investigated the biochemical changes in sOPCA and MSA to understand the relationship between these disorders. An initial study revealed decreased local cerebral metabolic rates for glucose in the brainstem, cerebellum, putamen, thalamus and cerebral cortex in both MSA and sOPCA, suggesting that many sOPCA patients would evolve to develop MSA. Later studies confirmed this by demonstrating decreased monoaminergic nigrostriatal terminals in both sOPCA and MSA patients. The studies suggest that the ligand used might be helpful in determining the risk that an individual patient with sOPCA will progress to develop MSA. An investigation of the course of sOPCA patients observed clinically over several years revealed that approximately one-fourth of them progress to MSA within five years. Studies of gamma-aminobutyric acid type A/benzodiazepine neurotransmitter receptors revealed that these sites are largely preserved in sOPCA and MSA, indicating that symptomatic pharmacological therapy may be possible in these disorders.

Sensory disturbances after focal extirpations of the human "motor" cortex

From the late 1800s until approximately the middle of the 20th century, neurosurgeons made discrete motor cortex lesions in humans in attempts to reduce or eliminate a variety of involuntary movements, resulting mainly from epilepsy. In some cases, the neurosurgeons tested and recorded their patients' ability to perform various movements and to perceive various types of sensory stimuli after the operation. Although these studies have been largely forgotten, they have an immense advantage over primate lesion studies for understanding the function of the motor cortex because the patients were able to attempt to perform complex movements upon request, and to describe their perceptions of cutaneous stimuli, including integrated sensations (e.g., recognition of objects by palpation alone). We provide here a table containing the results of these studies pertaining to sensory deficits. The most consistent and persistent sensory deficits reported relate to object recognition and position sense. This finding is in keeping with recent electrophysiological studies in primates. Our analysis suggests that the "motor" cortex serves important sensory functions; hence, the term sensorimotor cortex, remains appropriate for the primate precentral (and postcentral) cortex.

Neuropathological correlates of dysarthria in progressive supranuclear palsy

BACKGROUND

The dysarthria of progressive supranuclear palsy consists of prominent hypokinetic and spastic components with less prominent ataxic components.

OBJECTIVE

To correlate the types of dysarthria with neuropathological changes in patients with progressive supranuclear palsy.

DESIGN AND METHODS

In 14 patients with progressive supranuclear palsy, we correlated the perceptual speech findings with the neuropathological findings. A dysarthria assessment was performed a mean +/- SD of 31 +/- 15 months (range, 10-53 months) before death. The deviant speech dimensions were rated on a scale of 0 (normal) to 3 (severe). The neuropathological examination consisted of semiquantitative analysis of neuronal loss and gliosis by investigators (A.A.F.S., and L.A.B.) blinded to the clinical findings. Correlation and linear regression analysis were used to correlate the severity of the hypokinetic, spastic, and ataxic components with the degree of neuronal loss and gliosis in predetermined anatomical sites.

RESULTS

All patients had hypokinetic and spastic dysarthria, and 9 also had ataxic components. The severity of the hypokinetic components was significantly correlated with the degree of neuronal loss and gliosis in the substantia nigra pars compacta (r = 0.61, P =.02) and pars reticulata (r = 0.64, P =.01) but not in the subthalamic nucleus (r = 0.51, P =.07) or the striatum or globus pallidus (/r/<0.34, P>.20). The severity of the spastic and ataxic components was not significantly correlated with the neuropathological changes in the frontal cortex (r = 0.20, P =.50) and cerebellum (/r/<0.28, P>.33), respectively.

CONCLUSION

The hypokinetic dysarthria of progressive supranuclear palsy may result from degenerative changes in the substantia nigra pars compacta and pars reticulata and not from changes in the striatum or globus pallidus.

Integrating the work of D. Denny-Brown and some of his contemporaries into current studies of the primate motor cortex

Most contemporary investigators who study the behavioral effects of lesions of the primate motor cortex evaluate their findings in comparison to those of other recent investigators, but not in relation to the experimental neurologists who dominated this field around the mid-part of the 20th century. Utilizing selected recent reports, we demonstrate that these earlier papers, primarily those by D. Denny-Brown, provide valuable insights into the interpretation of some modern studies. Thus, we suggest that contemporary investigators of the primate motor cortex thoroughly review articles by the mid-20th century experimental neurologists. In addition, Denny-Brown and his contemporaries studied the effects of lesions in many other parts of the primate nervous system, and the associated reports are presumably also relevant to current investigations of these areas of the CNS.

The spinocerebellar ataxias

The spinocerebellar ataxias (SCAs) are diseases characterized by the progressive degeneration and subsequent loss of neurons accompanied by reactive gliosis, degeneration of fibers from the deteriorating neurons, and clinical symptoms reflecting the locations of the lost neurons. The degenerative changes affect specific neuronal groups while others remain preserved, and these diseases can therefore be viewed as system degenerations. The SCAs result from either genetically transmitted diseases with dominant inheritance or unknown causes with sporadic occurrence. Most of these disorders affect the cerebellum and its pathways, resulting in progressive deterioration of cerebellar function manifested by increasing unsteadiness of gait, incoordination of limb movements with impairment of skilled movements such as handwriting, and a distinctive dysarthria. Other neuronal systems are affected in some of these disorders, notably the corticospinal pathway, basal ganglia, and autonomic nuclei of the brain stem and spinal cord.

Evolution of sporadic olivopontocerebellar atrophy into multiple system atrophy

OBJECTIVE

To determine the percentage of sporadic olivopontocerebellar atrophy (sOPCA) patients who later develop multiple system atrophy (MSA).

METHODS

Observations of the course of 51 sOPCA patients 20 years of age or older initially evaluated in an ataxia clinic over 14 years and followed at 3- to 6-month intervals for 3 months to 10 years (median 2.5 years, interquartile range 5 months to 4 years).

RESULTS

Seventeen patients evolved to develop MSA, whereas the remaining 34 manifested only progressively worsening cerebellar ataxia. The features of the MSA cases included autonomic failure and parkinsonism in 10 patients, autonomic failure without parkinsonism in six, and parkinsonism without autonomic failure in one. Using survival analysis methods, the authors estimated that 24% of subjects in this population will evolve to MSA within 5 years of the onset of sOPCA symptoms (95% CI 10% to 36%). An older age at onset of symptoms and a shorter time from onset of symptoms to first presentation in a neurology specialty clinic were both highly predictive of evolution to MSA. Six of the 17 patients who evolved to MSA died 4 months to 5 years after they had met diagnostic criteria for MSA. The estimated median survival time from time of transition was 3.5 years. In contrast, death occurred in only one of the 34 patients with sOPCA who did not evolve to MSA. Autopsy examination of all six patients with MSA who died confirmed the diagnosis.

CONCLUSIONS

Approximately one-fourth of sporadic olivopontocerebellar atrophy patients will evolve to multiple system atrophy within 5 years, and this transition carries a poor prognosis for survival. Older age at onset of ataxia and earlier presentation in a neurologic specialty clinic predicted transition to MSA.

PET measures of benzodiazepine receptors in progressive supranuclear palsy

OBJECTIVE

To evaluate the integrity of neurons containing benzodiazepine receptors in metabolically affected regions of the brain in patients with clinically diagnosed progressive supranuclear palsy (PSP).

METHODS

The cerebral distribution of [11C]flumazenil (FMZ), a ligand that binds to the gamma-aminobutyric acid A (GABAA) receptor, and [18F]fluorodeoxyglucose (FDG), a measure of local cerebral glucose metabolism, was determined with PET in 12 patients with PSP and 10 normal control subjects. Tracer kinetic analysis was applied to quantify data and analysis was performed using three-dimensional stereotactic surface projections and stereotactically determined volumes of interest.

RESULTS

There was a global reduction in FMZ binding of 13%, with a reduction in the anterior cingulate gyrus of 20% (p = 0.004), where glucose metabolic rates also showed the greatest reduction.

CONCLUSIONS

PSP causes loss of benzodiazepine receptors in the cerebral cortex. Consistent with postmortem studies, the authors did not find significant changes in FMZ binding in subcortical nuclei that exhibit the most pathologic change. This study suggests that both loss of intrinsic neurons containing benzodiazepine receptors and deafferentation of the cerebral cortex from distant brain regions contribute to cerebral cortical hypometabolism in PSP.

Hereditary ataxias

There are many causes of hereditary ataxia. These can be grouped into categories of autosomal recessive, autosomal dominant, and X-linked. Molecularly, many of them are due to trinucleotide repeat expansions. In Friedreich ataxia, the trinucleotide repeat expansions lead to a "loss of function." In the dominant ataxias, the expanded repeats lead to a "gain of function," most likely through accumulation of intranuclear (and less commonly cytoplasmic) polyglutamine inclusions. Channelopathies can also lead to ataxia, especially episodic ataxia. Although phenotypic characteristics are an aid to the clinician, a definitive diagnosis is usually made only through genotypic or molecular studies. Genetic counseling is necessary for the testing of symptomatic and asymptomatic individuals. No effective treatment is yet available for most ataxic syndromes, except for ataxia with isolated vitamin E deficiency and the episodic ataxias.

An autosomal genomic screen for autism. Collaborative linkage study of autism

Autism is a severe neurodevelopmental disorder defined by social and communication deficits and ritualistic-repetitive behaviors that are detectable in early childhood. The etiology of idiopathic autism is strongly genetic, and oligogenic transmission is likely. The first stage of a two-stage genomic screen for autism was carried out by the Collaborative Linkage Study of Autism on individuals affected with autism from 75 families ascertained through an affected sib-pair. The strongest multipoint results were for regions on chromosomes 13 and 7. The highest maximum multipoint heterogeneity LOD (MMLS/het) score is 3.0 at D13S800 (approximately 55 cM from the telomere) under the recessive model, with an estimated 35% of families linked to this locus. The next highest peak is an MMLS/het score of 2.3 at 19 cM, between D13S217 and D13S1229. Our third highest MMLS/het score of 2.2 is on chromosome 7 and is consistent with the International Molecular Genetic Study of Autism Consortium report of a possible susceptibility locus somewhere within 7q31-33. These regions and others will be followed up in the second stage of our study by typing additional markers in both the original and a second set of identically ascertained autism families, which are currently being collected. By comparing results across a number of studies, we expect to be able to narrow our search for autism susceptibility genes to a small number of genomic regions. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:609-615, 1999.

[Consensus on the diagnosis of multi-system atrophy]

We report the results of a consensus conference on the diagnosis of multiple system atrophy. We describe the clinical features of the disease, which include four domains: autonomic failure/urinary dysfunction, parkinsonism and cerebellar ataxia, and corticospinal dysfunction. We set criteria to define the relative importance of these features. The diagnosis of possible multiple system atrophy requires one criterion plus two features from separate domains. The diagnosis of probable multiple system atrophy requires the criterion for autonomic failure/urinary dysfunction plus poor levodopa responsive parkinsonism or cerebellar ataxia. The diagnosis of definite multiple system atrophy requires pathological confirmation.