Mutational spectrum of the CHAC gene in patients with chorea-acanthocytosis.

Chorea-acanthocytosis (ChAc) is an autosomal recessive neurological disorder whose characteristic features include hyperkinetic movements and abnormal red blood cell morphology. Mutations in the CHAC gene on 9q21 were recently found to cause chorea-acanthocytosis. CHAC encodes a large, novel protein with a yeast homologue implicated in protein sorting. In this study, all 73 exons plus flanking intronic sequence in CHAC were screened for mutations by denaturing high-performance liquid chromatography in 43 probands with ChAc. We identified 57 different mutations, 54 of which have not previously been reported, in 39 probands. The novel mutations comprise 15 nonsense, 22 insertion/deletion, 15 splice-site and two missense mutations and are distributed throughout the CHAC gene. Three mutations were found in multiple families within this or our previous study. The preponderance of mutations that are predicted to cause absence of gene product is consistent with the recessive inheritance of this disease. The high proportion of splice-site mutations found is probably a reflection of the large number of exons that comprise the CHAC gene. The CHAC protein product, chorein, appears to have a certain tolerance to amino-acid substitutions since only two out of nine substitutions described here appear to be pathogenic.

Accuracy of muscle localization without EMG: implications for treatment of limb dystonia.

Although botulinum toxin is an effective treatment for focal dystonia, the importance of electromyography (EMG) in identifying muscles and guiding injections is unclear. The authors examined the accuracy of muscle localization in 38 muscles in patients with focal hand dystonia without EMG guidance. Only 37% of needle placement attempts reached the target muscles or muscle fascicles. This study demonstrates that EMG guidance is needed for correct localization of desired muscles.

Abnormal neurologic maturation in adolescents with early-onset schizophrenia.

OBJECTIVE: This study evaluated neurologic functioning in adolescents with schizophrenia with onset of psychosis before age 13. METHOD: The authors administered a structured neurologic examination to 21 adolescents with early-onset schizophrenia and 27 healthy age- and sex-matched comparison subjects. RESULTS: The adolescents with schizophrenia had a high frequency of neurologic abnormalities. Neurologic signs decreased with age in the healthy comparison subjects but not in the subjects with schizophrenia. CONCLUSIONS: The adolescents with schizophrenia had a high burden of neurologic impairment and a pattern of abnormalities similar to that of adults with schizophrenia. The persistence of neurologic signs in the adolescents with schizophrenia, which faded with age in the healthy comparison adolescents, supports earlier evidence of a delay in or failure of normal brain development during adolescence.

An open trial of clozapine for dystonia.

Pharmacologic treatment of severe dystonia is often unsatisfactory. The atypical antipsychotic medication clozapine appears to improve tardive dystonia associated with conventional neuroleptic use. We studied the efficacy of clozapine for severe dystonia in five patients in an open trial. The patient cohort included four with generalized dystonia and one with Meige syndrome. All patients were evaluated at baseline and at least weekly while on medication with subjective assessment of response by the patient and physician rating using the Burke-Fahn-Marsden Evaluation Scale for Dystonia. All five subjects had significant improvement detected by the Burke-Fahn-Marsden Evaluation Scale as well as subjective improvement while on clozapine. Side effects, such as sedation and orthostatic hypotension, developed in all patients but was only treatment-limiting in one subject who developed persistent symptomatic orthostatic hypotension and tachycardia. Two of the four remaining patients continued clozapine after completion of the study; an additional patient was uncertain if the benefit outweighed the side effects. One patient discontinued treatment because of difficulty obtaining the FDA-required weekly white blood cell counts for patients on clozapine. We conclude that clozapine appears to be effective for generalized and refractory focal dystonia although its use may be limited by the side effects and need for hematologic monitoring.

Effect of muscle activity immediately after botulinum toxin injection for writer's cramp.

Animal and human studies have shown that nerve stimulation enhances some effects of botulinum toxin (btx A) injection. Voluntary muscle activity might work similarly and would focus the effect of an injection into the active muscles. We studied the effects of exercise immediately after btx A injection in eight patients with writer's cramp with established response to btx A over two injection cycles with a single-blinded, randomized, crossover design. Immediately after the first study injection, they were randomly assigned to write continuously for 30 min or have their hand and forearm immobilized for 30 min. Following the second injection, they were assigned the alternate condition. Patients were assessed just before each injection, and at 2 weeks, 6 weeks, and 3 months post-injection. Assessment included objective strength testing, self-reported rating of benefit and weakness, and blinded evaluation of videotapes and writing samples of the patients writing a standard passage. Strength testing showed that the maximum weakness occurred at 2 weeks post-injection, but the benefit was maximum at 6 weeks post-injection. The "write" condition resulted in greater reduction in strength than the "rest" condition. Btx A treatment led to improvement in self-reported ratings, writer's cramp rating scale scores by blinded raters, and reduction in writing time, but the differences between the "write" and "rest" conditions were not significant. We conclude that voluntary muscle activity immediately after btx A injection leads to greater reduction in muscle strength. Our findings raise the possibility that voluntary muscle activation may allow reduction of btx A doses and favorably alter the balance of benefit and side effects of btx A injections.

Pallidal activity during dystonia: somatosensory reorganisation and changes with severity.

A woman with progressive, medically intractable right upper limb dystonia underwent a pallidotomy with only transient improvement. During the procedure her dystonia became more severe as she repeatedly made a fist to command in order to provoke dystonia transiently (movement provoked dystonia). Comparisons within cells in the internal segment of the globus pallidus (Gpi) disclosed that the firing rate was the same at rest, with making a fist, and during movement provoked dystonia. However, the firing rate compared between cells decreased significantly throughout the procedure as the patient made a fist repeatedly. During the second half of the procedure the firing rate of cells in the Gpi was similar to that in hemiballismus. The proportion of cells in the GPi which responded to sensory stimulation was significantly higher in dystonia (53%) than in hemiballismus (13%). These results suggest that pallidal activity can correlate inversely with the severity of dystonia, perhaps due to activity dependent changes in neuronal function resulting from repeated voluntary movement.

Botulinum toxin type F for treatment of dystonia: long-term experience.

The authors analyzed retrospectively the results of open-labeled botulinum toxin type F (BTXF) treatment for 1 year or longer in 18 BTXA-resistant patients. All patients except one primary nonresponder to BTXA improved initially with BTXF. Most patients continued to respond to BTXF for 1 year or longer, but four patients became resistant to BTXF. BTXF-resistant patients received a higher dose per treatment and a higher cumulative dose than BTXF-responsive patients. BTXF can be used for long-term treatment of dystonia. It seems prudent to limit BTX doses of all serotypes to the lowest necessary for clinical efficacy.

Childhood-onset schizophrenia: an open-label study of olanzapine in adolescents.

OBJECTIVE: Olanzapine, a potent 5-HT2a/2c, dopamine D1D2D4 antagonist with anticholinergic activity, has a profile of known receptor affinity similar to that of clozapine. This pilot study examined the efficacy of olanzapine for treatment-refractory childhood-onset schizophrenia in eight patients who had received 8-week open-label trials. For comparison, data are included from 15 patients who had received 6-week open-label clozapine trials using identical rating instruments (largely by the same raters) in the same treatment setting. METHOD: Twenty-three children and adolescents with an onset of DSM-III-R schizophrenia by age 12 for whom at least two different typical neuroleptics had been ineffective participated in the two separate studies. Some of the patients were intolerant of clozapine, although it had been effective (n = 4). Patients receiving olanzapine were evaluated over 8 weeks with the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, and the Clinical Global Impressions Scale for Improvement. RESULTS: For the eight patients who received olanzapine trials, at week 8 there was a 17% improvement in the BPRS total score, a 27% improvement in the Scale for the Assessment of Negative Symptoms, and a 1% improvement in the Scale for the Assessment of Positive Symptoms, relative to "ideal" admission status on typical neuroleptics. In contrast, the magnitude of the effect sizes for each of the clinical ratings was larger at week 6 of the previous clozapine trial than for an 8-week olanzapine trial, relative to admission status on typical neuroleptics. For the four children who had received both clozapine and olanzapine, BPRS total scores were significantly lower at week 6 of clozapine treatment compared with week 6 of olanzapine treatment (p = .03). CONCLUSION: These data provide preliminary evidence for the efficacy of olanzapine for some children and adolescents with treatment-refractory schizophrenia, but they also suggest the need for a more rigorous double-blind comparison of these two atypical antipsychotics.

Case series: spectrum of neuroleptic-induced movement disorders and extrapyramidal side effects in childhood-onset schizophrenia.

OBJECTIVE: Neuroleptic-treated pediatric patients with childhood-onset schizophrenia (COS) are at risk for developing extrapyramidal side effects and involuntary movement disorders. A preliminary examination of the incidence of withdrawal dyskinesias (WD), tardive dyskinesia (TD), and extrapyramidal side effects in these patients is presented. METHOD: Thirty-four COS patients (mean age +/- SD, 14.2 +/- 2.1 years) were examined for TD using the Abnormal Involuntary Movements Scale and for extrapyramidal side effects using the Simpson-Angus Neurologic Rating Scale, after a 14- to 28-day drug-free period (n = 33), at week 6 of treatment and 2 to 4 years after completion of the study (n = 14). The mean (+/-SD) number of months of prior neuroleptic exposure for the group was 22.4 (15.0) months. RESULTS: Seventeen (50%) of 34 patients were noted to have either WD or TD at some point during their participation in the studies. The majority of patients experienced WD that were mainly in the orofacial region, transient in nature, and diminished with haloperidol and clozapine. Patients with TD/WD had greater levels of premorbid impairment (p = .02), increased severity of positive symptoms of schizophrenia (p < .01), and a trend toward more months of neuroleptic exposure (p = .10, one-tailed). CONCLUSIONS: A high proportion of COS patients were found to have TD/WD. The majority of these abnormal movements were not severe and generally improved over time. TD/WD in COS appears to be associated with greater premorbid impairment, severity of illness, and duration of neuroleptic exposure. J. Am. Acad.

Myelinolysis after correction of hyponatremia.

Myelinolysis is a neurologic disorder that can occur after rapid correction of hyponatremia. Initially named "central pontine myelinolysis," this disease is now known to also affect extrapontine brain areas. Manifestations of myelinolysis usually evolve several days after correction of hyponatremia. Typical features are disorders of upper motor neurons, spastic quadriparesis and pseudobulbar palsy, and mental disorders ranging from mild confusion to coma. Death may occur. The motor and localizing signs of myelinolysis differ from the generalized encephalopathy that is caused by untreated hyponatremia. Experiments have duplicated the clinical and pathologic features of myelinolysis by rapidly reversing hyponatremia in animals. Myelinolysis is more likely to occur after the treatment of chronic rather than acute hyponatremia and is more likely to occur with a rapid rate of correction. The exact pathogenesis of myelinolysis has not been determined. Optimal management of hyponatremic patients involves weighing the risk for illness and death from untreated hyponatremia against the risk for myelinolysis due to correction of hyponatremia. Experiments in animals and clinical experience suggest that correction of chronic hyponatremia should be kept at a rate less than 10 mmol/L in any 24-hour period.

Smooth pursuit eye movements in childhood-onset schizophrenia: comparison with attention-deficit hyperactivity disorder and normal controls.

Abnormalities of the smooth pursuit eye movements of adults with schizophrenia have been well described. We examined smooth pursuit eye movements in schizophrenic children, contrasting them with normal and attention-deficit hyperactivity disorder (ADHD) subjects, to determine whether there is continuity of eye movement dysfunction between childhood- and adult-onset forms of schizophrenia. Seventeen schizophrenic children with onset of illness by age 12, 18 ADHD children, and 22 normal children were studied while engaged in a smooth pursuit eye tracking task. Eye tracking variables were compared across the three groups. Schizophrenic children exhibited significantly greater smooth pursuit impairments than either normal or ADHD subjects. Within the schizophrenic group, there were no significant relationships between eye tracking variables and clinical variables, or ventricular/brain ratio. Childhood-onset schizophrenia is associated with a similar pattern of smooth pursuit abnormalities to that seen in later-onset schizophrenia.

Multiple cerebral lesions complicating therapy with interleukin-2.

We reviewed the records and radiologic studies of eight patients who developed new focal neurologic abnormalities while receiving interleukin-2 (IL2)-based immunotherapy for malignancy or HIV infection. Initial confusion and delirium in the patients evolved into coma, ataxia, hemiparesis, seizures, and cortical syndromes including aphasia, apraxia, and cortical blindness. Imaging studies showed multiple white and gray matter lesions with a predilection for the occipital poles, centrum semiovale, and cerebellum. After cessation of IL2 treatment, seven patients improved to normal or near-normal neurologic function paralleled by resolution of the lesions on scans. One patient improved only minimally. Possible etiologies for the lesions include an IL2-induced cerebral vasculopathy, a direct toxic effect of IL2, or immunologically mediated damage.

Simple motor tics may be preceded by a premotor potential.

Obeso et al reported that simple motor tics in Tourette's syndrome were not associated with premotor potentials, which were present when patients mimicked their tics voluntarily, suggesting that spontaneous tics were not generated in the same manner as voluntary movements. Five patients with simple motor tics were studied using a similar paradigm. Premotor potentials were examined during spontaneous tics and during voluntary imitation of the tics. All patients had premotor negativity with the voluntary movements. As in the study of Obeso et al, spontaneous tics were not preceded by premotor potentials in three patients. However, premotor negativity was present with spontaneous tics in two patients and resembled the NS' segment of the premotor potential seen with self paced, voluntary movements. A similar premotor potential pattern has been reported with voluntary movements performed in response to external triggering stimuli. In patients with Tourette's syndrome, the eliciting signals could be internal sensations.

Extracorporeal 'phantom' tics in Tourette's syndrome.

Some tics are intentional movements made in an attempt to diminish uncomfortable sensations. These sensations, sometimes termed sensory tics, are focal and usually arise in the part of the body involved in the subsequent motor act. We report a patient whose sensations associated with tics were felt in other people and in objects. The discomfort associated with his out-of-body sensations was temporarily relieved by touching or scratching the object involved. The definition of premonitory sensations should be expanded to include extracorporeal sensations, and a history of external sensations should be sought in patients with Tourette's syndrome. Theories on the generation of tics must incorporate an explanation for extracorporeal sensations.

Long-term botulinum toxin treatment of focal hand dystonia.

We treated focal hand dystonia in 53 patients with botulinum toxin injections for up to 6 years. Eighty-one percent of the patients improved with at least one injection session. Sixty-five percent of the injections produced transient weakness. We followed 37 of the patients for at least 2 years from the start of treatment, 24 of whom discontinued treatment because of inadequate response, loss of response, inaccessibility of a treatment provider, or the expense of the toxin. Women, who had a greater extent and longer duration of benefit than men, were more likely to continue treatment. The mean interval between injection sessions was 6 months. In most patients, we injected the toxin into the same combination of muscles at each session. The dose of toxin generally fluctuated within a range of 20 units. Side effects were mild and transient and unrelated to the long-term use of botulinum toxin. Botulinum toxin injection is safe and effective for the long-term management of focal hand dystonia.

Pontine and extrapontine myelinolysis: a neurologic disorder following rapid correction of hyponatremia.

Neurologic disorders developing after correction of severe, symptomatic hyponatremia were studied in 14 patients. None had a hypoxic event or other identifiable cause for the neurologic illness. Neurologic deterioration began about 3 days after correction and often followed a period of improvement in hyponatremic encephalopathy. Although the symptoms were as mild as transient confusion in 1 patient, they were more severe in the others. Typically, spastic quadriparesis, pseudobulbar palsy, and impairment in the level of consciousness progressed for up to 7 days. Improvement generally began 2 weeks after correction and continued for up to a year in some patients. Routine spinal fluid analysis was usually normal, but myelin basic protein concentration was elevated in all patients in whom it was measured. Electroencephalograms commonly showed nonfocal slowing. Brainstem auditory evoked potential latencies were prolonged in some patients. Brain imaging was normal in the initial week of illness, while later scans, obtained in 9 patients, showed central pontine and/or symmetric extrapontine lesions. The clinical manifestations and distribution of lesions seen on imaging demonstrate that neurologic illness following correction of hyponatremia is due to myelinolysis. Although this neurologic disorder typically followed an elevation in serum sodium > 18 mEq/L/24 hr, it sometimes followed a rise as slow as 10 mEq/L/24 hr and 21 mEq/L/48 hr. Whenever possible, the rate of correction of hyponatremia should be kept below these values in order to minimize the risk of myelinolysis.

Mental neuropathy (numb chin syndrome). A harbinger of tumor progression or relapse.

The authors report four patients whose initial symptom of tumor recurrence or progression was unilateral numbness of the chin. Two patients had Hodgkin lymphoma, one had malignant melanoma, and one had prostate cancer. Physical examination was notable only for unilateral anesthesia of the chin and lower lip. Diagnostic evaluation, including computed tomography (CT) scan and magnetic resonance imaging (MRI) of the brain, plain radiographs of the mandible, and cerebrospinal fluid analysis for protein, glucose, and cytology were normal. Bone scans revealed osseous lesions in the axial skeleton of all patients, whereas only two patients had abnormal uptake in the mandible. The authors conclude that in the setting of a negative evaluation for central nervous system (CNS) or local mandibular disease, mental neuropathy is associated with recurrent or progressive skeletal disease. In addition, to document relapsed or progressive cancer, the skeletal system may have to be examined at sites distant from the mandible.