Circadian rhythm studies in neuronal ceroid-lipofuscinosis (NCL)

Current Considerations in the Diagnosis and Treatment of Circadian Rhythm Sleep-Wake Disorders in Children

Circadian Rhythm Sleep-Wake Disorders (CRSWDs) are important sleep disorders whose unifying feature is a mismatch between the preferred or required times for sleep and wakefulness and the endogenous circadian drives for these. Their etiology, presentation, and treatment can be different in pediatric patients as compared to adults. Evaluation of these disorders must be performed while viewed through the lens of a patient's comorbid conditions. Newer methods of assessment promise to provide greater diagnostic clarity and critical insights into how circadian physiology affects overall health and disease states. Effective clinical management of CRSWDs is multimodal, requiring an integrated approach across disciplines. Therapeutic success depends upon appropriately timed nonpharmacologic and pharmacologic interventions. A better understanding of the genetic predispositions for and causes of CRSWDs has led to novel clinical opportunities for diagnosis and improved therapeutics.

Early postnatal administration of an AAV9 gene therapy is safe and efficacious in CLN3 disease

CLN3 disease, caused by biallelic mutations in the CLN3 gene, is a rare pediatric neurodegenerative disease that has no cure or disease modifying treatment. The development of effective treatments has been hindered by a lack of etiological knowledge, but gene replacement has emerged as a promising therapeutic platform for such disorders. Here, we utilize a mouse model of CLN3 disease to test the safety and efficacy of a cerebrospinal fluid-delivered AAV9 gene therapy with a study design optimized for translatability. In this model, postnatal day one administration of the gene therapy virus resulted in robust expression of human CLN3 throughout the CNS over the 24-month duration of the study. A range of histopathological and behavioral parameters were assayed, with the therapy consistently and persistently rescuing a number of hallmarks of disease while being safe and well-tolerated. Together, the results show great promise for translation of the therapy into the clinic, prompting the launch of a first-in-human clinical trial (NCT03770572).

Workshop report. Circadian rhythm sleep-wake disorders: gaps and opportunities

This White Paper presents the results from a workshop cosponsored by the Sleep Research Society (SRS) and the Society for Research on Biological Rhythms (SRBR) whose goals were to bring together sleep clinicians and sleep and circadian rhythm researchers to identify existing gaps in diagnosis and treatment and areas of high-priority research in circadian rhythm sleep-wake disorders (CRSWD). CRSWD are a distinct class of sleep disorders caused by alterations of the circadian time-keeping system, its entrainment mechanisms, or a misalignment of the endogenous circadian rhythm and the external environment. In these disorders, the timing of the primary sleep episode is either earlier or later than desired, irregular from day-to-day, and/or sleep occurs at the wrong circadian time. While there are incomplete and insufficient prevalence data, CRSWD likely affect at least 800,000 and perhaps as many as 3 million individuals in the United States, and if Shift Work Disorder and Jet Lag are included, then many millions more are impacted. The SRS Advocacy Taskforce has identified CRSWD as a class of sleep disorders for which additional high-quality research could have a significant impact to improve patient care. Participants were selected for their expertise and were assigned to one of three working groups: Phase Disorders, Entrainment Disorders, and Other. Each working group presented a summary of the current state of the science for their specific CRSWD area, followed by discussion from all participants. The outcome of those presentations and discussions are presented here.

Neuronal ceroid lipofuscinosis: genetic and phenotypic spectrum of 14 patients from Turkey

INTRODUCTION AND PURPOSE

Neuronal ceroid lipofuscinoses (NCLs) is a group of congenital metabolic diseases where the neurodegenerative process with the accumulation of ceroid and lipofuscin autofluorescent storage materials is at the forefront. According to the age of presentation, NCLs are classified as congenital, infantile (INCL), late infantile (LINCL), juvenile (JNCL), and adult (ANCL) NCLs. In our study, it was aimed to discuss the clinical and molecular characteristics of our patients diagnosed with NCL.

MATERIAL AND METHOD

This is a descriptive cross-sectional study which was conducted in 14 patients from 10 unrelated families who were diagnosed with different types of NCL based on clinical presentation, neuroimaging, biochemical measurements, and molecular analyses, at the department of pediatric metabolism between June 2015 and June 2020.

RESULTS

A total of 14 patients were diagnosed with different types of NCL. Of those, 4 patients were diagnosed with NCL7 (4/14; 30%), 3/14 (23%) with NCL1, 3/14 (23%) with NCL2, 2/14 (14.2%) with NCL13, and 1/14 (7.1%) with NCL10. Eleven pathogenic variants were detected, 5 of which are novel (c.721G>T [p.Gly241Ter] and c.301G>C [p.Ala146Pro] in MFDS8 gene; c.316C>T [p.Gln106Ter] in PPT1 gene; c.341C>T [p.Ala114Val] in TPP1 gene; c.686A>T [p.Glu229Val] in CTSD gene) CONCLUSION: This study is one of the pioneer comprehensive researches from Turkey that provides information about disease-causing variants and clinical presentation of different and rare types of NCLs. The identification of novel variants and phenotypic expansion is important for genetic counselling in Turkey and expected to improve understanding of NCLs.

Juvenile neuronal ceroid lipofuscinosis (Batten disease): current insights

The present review is focused on juvenile neuronal ceroid lipofuscinosis (JNCL; Batten disease) due to a mutation in CLN3. Functional vision impairment occurring around 5-6 years of age is the first symptom in more than 80% of patients. Approximately 2 years later (though sometimes simultaneously), obvious signs of cognitive impairment appear. Behavior problems can occur in advance, especially in boys. These include anxious and depressed mood, aggressive behavior, and hallucinations, and even psychotic symptoms. Following the teens, severe dementia is present, including loss of memory, attention, and general reasoning abilities, as well as loss of independent adaptive skills such as mobility, feeding, and communicating. Sleep abnormalities, such as settling problems, nocturnal awakenings, and nightmares, are reported in more than half of patients. The vast majority, if not all, patients develop seizures, starting at approximately 10 years of age. Generalized tonic-clonic seizure occurs as the only type of seizure in approximately half of patients, and in combination with partial seizures in a third of patients. There seems to be no difference in seizure severity according to sex or genotype, and there is great variation in seizure activity among patients. Soon after diagnosis, patients begin to have slight ataxic symptoms, and at adolescence extrapyramidal symptoms (rigidity, bradykinesia, slow steps with flexion in hips and knees) occur with increasing frequency. Chewing and swallowing difficulties emerge as well, and food intake is hampered in the late teens. Disabling periodically involuntary movements may occur as well. A progressive cardiac involvement with repolarization disturbances, ventricular hypertrophy, and sinus-node dysfunction, ultimately leading to severe bradycardia and/or other conduction abnormalities, starts in the mid-teens. Patients are usually bedridden at 20 years of age, and death usually occurs in the third decade of life.

Neuronal Ceroid Lipofuscinosis and Associated Sleep Abnormalities

PURPOSE

The aims of this study were to evaluate sleep difficulties in children with neuronal ceroid lipofuscinosis and to determine the association between the sleep difficulties and the onset of seizures and loss of vision.

METHOD

We recruited individuals with a confirmed diagnosis of neuronal ceroid lipofuscinosis. We obtained information from the caregiver using the validated Children's Sleep Habits Questionnaire which is a sleep instrument for both behaviorally and medically based problems. Additional information was collected including onset of symptoms, treatment trials, and screen for restless leg syndrome symptoms.

RESULTS

In our cohort of 54 individuals, 96.3% had sleep scores consistent with a sleep disturbance. Sleep subscale analysis provided additional insight into the characteristics of the sleep disturbance. Fifty two of the 54 patients had at least one abnormal sleep subscale. The onset of sleep disturbance was associated with the onset of both seizures (ρ = 0.5834, P < 0.0001) and loss of vision (ρ = 0.3840, P = 0.0084). Restless leg syndrome symptoms were reported in 35.2%.

CONCLUSION

Children with neuronal ceroid lipofuscinosis have a high burden of sleep disturbances. Using the results of a sleep disturbance screening tool can help to identify the most disturbing symptoms. Targeted treatment of sleep disturbance may improve the quality of life for the patient and family.

Moving towards effective therapeutic strategies for Neuronal Ceroid Lipofuscinosis

The Neuronal Ceroid Lipofuscinoses (NCLs) are a family of autosomal recessive neurodegenerative disorders that annually affect 1:100,000 live births worldwide. This family of diseases results from mutations in one of 14 different genes that share common clinical and pathological etiologies. Clinically, the diseases are subcategorized into infantile, late-infantile, juvenile and adult forms based on their age of onset. Though the disease phenotypes may vary in their age and order of presentation, all typically include progressive visual deterioration and blindness, cognitive impairment, motor deficits and seizures. Pathological hallmarks of NCLs include the accumulation of storage material or ceroid in the lysosome, progressive neuronal degeneration and massive glial activation. Advances have been made in genetic diagnosis and counseling for families. However, comprehensive treatment programs that delay or halt disease progression have been elusive. Current disease management is primarily targeted at controlling the symptoms rather than "curing" the disease. Recognizing the growing need for transparency and synergistic efforts to move the field forward, this review will provide an overview of the therapeutic approaches currently being pursued in preclinical and clinical trials to treat different forms of NCL as well as provide insight to novel therapeutic approaches in development for the NCLs.

Mice heterozygous for cathepsin D deficiency exhibit mania-related behavior and stress-induced depression

Mutations in cathepsin D (CTSD), an aspartic protease in the endosomal-lysosomal system, underlie congenital neuronal ceroid-lipofuscinosis (cNCL, also known as CLN10), a devastating neurodegenerative disease. CLN10 patients die within the first few days of life, and in the few patients who live into adulthood psychopathological symptoms have not been reported. Extensive neuropathology and altered neurotransmission have been reported in CTSD-deficient mice; however signs of neuropsychiatric behavior in these mice are not well characterized due to the severe movement disorder and premature death of the animal. In the present study, we show that heterozygous CTSD-deficient (CTSD HET) mice display an overall behavioral profile that is similar to human mania, including hyperlocomotion, d-amphetamine-induced hyperactivity, sleep-disturbance, and reduced anxiety-like behavior. However, under stressful conditions CTSD HET mice manifest depressive-like behavior, including anhedonia, behavioral despair, and enhanced learned helplessness. Chronic administration of lithium chloride or valproic acid, two clinically effective mood stabilizers, reverses the majority of these behavioral abnormalities. In addition, CTSD HET mice display stress-induced hypersecretion of corticosterone. These findings suggest an important role for CTSD in the regulation of mood stabilization.

Irregular Sleep-Wake Rhythm Disorder

Irregular sleep-wake rhythm disorder is a circadian rhythm disorder characterized by multiple bouts of sleep within a 24-hour period. Patients present with symptoms of insomnia, including difficulty either falling or staying asleep, and daytime excessive sleepiness. The disorder is seen in a variety of individuals, ranging from children with neurodevelopmental disorders, to patients with psychiatric disorders, and most commonly in older adults with neurodegenerative disorders. Treatment of irregular sleep-wake rhythm disorder requires a multimodal approach aimed at strengthening circadian synchronizing agents, such as daytime exposure to bright light, and structured social and physical activities. In addition, melatonin may be useful in some patients.

Use of actigraphy for assessment in pediatric sleep research

The use of actigraphs, or ambulatory devices that estimate sleep-wake patterns from activity levels, has become common in pediatric research. Actigraphy provides a more objective measure than parent-report, and has gained popularity due to its ability to measure sleep-wake patterns for extended periods of time in the child's natural environment. The purpose of this review is: 1) to provide comprehensive information on the historic and current uses of actigraphy in pediatric sleep research; 2) to review how actigraphy has been validated among pediatric populations; and 3) offer recommendations for methodological areas that should be included in all studies that utilize actigraphy, including the definition and scoring of variables commonly reported. The poor specificity to detect wake after sleep onset was consistently noted across devices and age groups, thus raising concerns about what is an "acceptable" level of specificity for actigraphy. Other notable findings from this review include the lack of standard scoring rules or variable definitions. Suggestions for the use and reporting of actigraphy in pediatric research are provided.

Children with infantile neuronal ceroid lipofuscinosis have an increased risk of hypothermia and bradycardia during anesthesia

BACKGROUND

Neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative diseases characterized by lysosomal accumulation of autofluorescent material in neurons and other cell types. The infantile NCL (INCL) subtype is rare (1 in >100,000 births), the most devastating of childhood subtypes, and is caused by mutations in the gene CLN1, which encodes palmitoyl-protein thioesterase-1.

METHODS

To investigate the incidence of hypothermia and bradycardia during general anesthesia in patients with INCL, we conducted a case-control study to examine the perianesthetic course of patients with INCL and of controls receiving anesthesia for diagnostic studies.

RESULTS

Eight children with INCL (mean age 25 mo [range, 10-32] at first anesthetic) and 25 controls (mean age 44 mo [range, 18-92]) underwent 62 anesthetics for nonsurgical procedures. Patients with INCL had neurologic deficits including developmental delay, myoclonus, and visual impairment. Patients with INCL had lower baseline temperature (36.4 +/- 0.1 vs 36.8 +/- 0.1, INCL versus controls, P < 0.007), and during anesthesia, despite active warming techniques, had significantly more hypothermia (18 vs 0 episodes, P < 0.001) and sinus bradycardia (10 vs 1, P < 0.001) compared with controls. INCL diagnosis was significantly associated with temperature decreases during anesthesia (P < 0.001), whereas age, sex, and duration of anesthesia were not (P = NS).

CONCLUSIONS

We report that patients with INCL have lower baseline body temperature and during general anesthesia, despite rewarming interventions, are at increased risk for hypothermia and bradycardia. This suggests a previously unknown INCL phenotype, impaired thermoregulation. Therefore, when anesthetizing these children, careful monitoring and routine use of warming interventions are warranted.

A randomized, placebo-controlled trial of controlled release melatonin treatment of delayed sleep phase syndrome and impaired sleep maintenance in children with neurodevelopmental disabilities

The purpose of this study was to determine the efficacy of controlled-release (CR) melatonin in the treatment of delayed sleep phase syndrome and impaired sleep maintenance of children with neurodevelopmental disabilities including autistic spectrum disorders. A randomized double-blind, placebo-controlled crossover trial of CR melatonin (5 mg) followed by a 3-month open-label study was conducted during which the dose was gradually increased until the therapy showed optimal beneficial effects. Sleep characteristics were measured by caregiver who completed somnologs and wrist actigraphs. Clinician rating of severity of the sleep disorder and improvement from baseline, along with caregiver ratings of global functioning and family stress were also obtained. Fifty-one children (age range 2-18 years) who did not respond to sleep hygiene intervention were enrolled. Fifty patients completed the crossover trial and 47 completed the open-label phase. Recordings of total night-time sleep and sleep latency showed significant improvement of approximately 30 min. Similarly, significant improvement was observed in clinician and parent ratings. There was additional improvement in the open-label somnolog measures of sleep efficiency and the longest sleep episode in the open-label phase. Overall, the therapy improved the sleep of 47 children and was effective in reducing family stress. Children with neurodevelopmental disabilities, who had treatment resistant chronic delayed sleep phase syndrome and impaired sleep maintenance, showed improvement in melatonin therapy.

Endogenous melatonin predicts efficacy of exogenous melatonin in consolidation of fragmented wrist-activity rhythm of adult patients with developmental brain disorders: A double-blind, placebo-controlled, crossover study

OBJECTIVE

: We studied whether the endogenous melatonin patterns in adult patients with developmental brain disorders have any role in response to exogenous melatonin given as a sleep-promoting medicine.

METHODS

: Participants included 15 adults (18-60 years, five females) with developmental brain disorders of varying etiologies, motor handicaps, and long-term history of sleep problems. According to the 24-h patterns of serum melatonin, patients were divided into two subgroups: lower and higher secretors. The pretreatment sleep disorder was characterized by a structured interview, 24-h ambulatory polysomnography and 7-day wrist actigraphy. Patients received 1, 3, or 6mg fast-release melatonin tablets, each for 4 weeks in increasing order, at a constant time of 30min before the desired sleep onset. Similarly, placebos with different codes were given during 3x4 weeks. The 7-day actigraphy was repeated at the end of each drug period. Outcome measures were six different parameters of non-parametric circadian rhythm analysis. Drug effects and 40 confounding/modulating factors were evaluated by applying two-level regression analyses with co-variables.

RESULTS

: Exogenous melatonin decreased the fragmentation of the rest-activity rhythm, increased the day/night ratio of activity and advanced the onset of rest period. The effects on fragmentation and day/night ratio were more pronounced in the lower than higher secretors of melatonin. Other contributing factors in the drug effects were blindness and some features of the original sleep disorder (disrupted cyclicity of the sleep architecture in polysomnography or reported daytime somnolence).

CONCLUSIONS

: Exogenous melatonin consolidated the fragmented rest-activity in about half of the patients. Low endogenous serum melatonin levels at night predicted improvement by the drug. Higher doses were not more effective than the lowest dose.

Wrist actigraphy in estimation of sleep and wake in intellectually disabled subjects with motor handicaps

BACKGROUND AND PURPOSE

We studied the applicability of wrist actigraphy to sleep-wake estimation in patients with motor handicaps.

PATIENTS AND METHODS

Concomitant polysomnographic and actigraphic recordings (16-24 h) were compared in three groups: normally moving subjects with normal sleep (n=10), sleep-disordered subjects without motor handicaps (n=13) and sleep-disordered patients with different motor disabilities (n=16). The motor abilities of the subjects were determined by clinical evaluation using a grading scale from 0 to 10. Their actual daily activity was calculated from the recordings as average activity scores.

RESULTS

In the healthy subjects, the mean difference between actigraphic and polysomnographic total sleep estimation was negligible (-1 min), while in both sleep-disordered groups, sleep was highly overestimated by actigraphy. There was a significant correlation between the motor ability score and the discrepancy between actigraphy and polysomnography, but individual data points were highly scattered. A more consistent correlation was found between the average activity score/min in actigrams and the discrepancy of actigraphic with polysomnographic total sleep estimation (Spearman's r=-0.58, P=0.0001, n=39). When the recordings with very low average activity score were rejected from the analyses (two patients without and six with motor handicaps), the overestimation of sleep by actigraphy was reduced but it still remained in both sleep-disordered groups. The mean differences of total sleep between actigraphy and polysomnography were 72 and 121 min and the rank order correlation coefficients 0.80 and 0.71 in patients without and with motor handicaps, respectively. The median discrepancy in total sleep estimation was 6% in both sleep-disordered groups.

CONCLUSIONS

In subjects with rudimentary motor abilities, a standard actigraphy can produce a signal, which is related to the amount of sleep scored in polysomnograms. The sleep parameters obtained by the two methods are not equal, however. The inspection of actigrams is more reliable than the clinical scaling of motor abilities in predicting the applicability of wrist actigraphy.

Anesthetic management for a patient with Jansky-Bielschowsky disease

PURPOSE

To describe the anesthetic management of a patient with Jansky-Bielschowsky disease (JBD), the late infantile form of neuronal ceroid lipofuscinosis, characterized by dementia, severe and drug resistant grand mal, myoclonic seizures, and blindness.

CLINICAL FEATURES

A 14-yr-old girl with JBD was scheduled for resection of a gingival tumour and an infected sinus in the sacral area. Her preanesthetic examination revealed extreme muscle atrophy and dementia. Grand mal, myoclonic seizures, and upper airway obstruction were frequent. Following iv induction with thiamylal, anesthesia was maintained with sevoflurane, N(2)O and O(2). Her trachea was intubated without using muscle relaxants. Muscle relaxants were not used during the operation. Apart from an intractable hypothermia, the intraoperative course was uneventful. The emergence of anesthesia was smooth, except for persisting seizures.

CONCLUSION

General anesthesia using thiamylal and sevoflurane provided satisfactory conditions during operation in a patient with JBD. Intraoperative hypothermia required particular attention.

Sleep and its disturbance in a variant form of late infantile neuronal ceroid lipofuscinosis (CLN5)

To examine the nature of sleep disturbance in patients with a variant form of late infantile neuronal ceroid lipofuscinosis (CLN5), we studied 12 patients (age range 7-32 years). We used a sleep questionnaire to assess sleep and its disturbances quantitatively. To identify the periodicity in the diurnal rest-activity rhythms, the motor activity level was recorded by activity monitors continuously for a 1-week period with concomitant sleep logs. In addition, whole-night polysomnographic recordings were performed. The patients under 20 years of age had an excess of nocturnal sleep (the mean of the usual duration of nighttime sleep was 10.0 hours) and frequent daytime naps. Frequent shifts of the longest sleep period into the daytime hours and fragmented diurnal rest-activity patterns with no distinct rhythm occurred in the older patients. The progressive disease may damage the internal circadian timing system and also impair the ability of patients with variant late infantile neuronal ceroid lipofuscinosis to use external time cues for synchronization of their sleep and environmental time.

Circadian rhythms: interactions with seizures and epilepsy

Circadian rhythms are endogenously-mediated 24 h cycles of behavioral or physiological activity. The interactions among the mammalian circadian clock, acute seizures, and chronic epilepsy are not well-characterized. Evidence suggests that seizures are susceptible to circadian modulation, and that this modulation varies with epilepsy syndrome and location of seizure foci. The circadian timing system and secondary circadian cycles of hormone secretion, sleep and wakefulness, and recurrent environmental factors are discussed as potential systems that effect spontaneous seizure recurrence. Experimental designs should take into account time-of-day effects on seizure threshold and occurrence. Further work is required to determine what mechanisms account for daily variation in seizure susceptibility.

Sleep alterations in juvenile neuronal ceroid-lipofuscinosis

In juvenile neuronal ceroid-lipofuscinosis (JNCL), sleep disorders are common. The purpose of this study was to investigate the sleep structure of 28 patients with JNCL compared with healthy controls subjects and to clarify the pathophysiology underlying the sleep disturbances in these patients. Each of 28 patients with JNCL (age range = 6-27 years), with or without sleep complaints, underwent one night of polysomnography. Electroencephalographic, electro-oculographic, electromyographic, and electrocardiographic findings were recorded. Sleep was scored and analyzed visually. The sleep parameters of the patients were compared with those of healthy control subjects. In most of the patients, the total sleep time, sleep efficiency, and percentages of rapid eye movement (REM) and non-REM (NREM) stage 2 sleep were significantly decreased, and the percentages of NREM stage 1 and slow-wave sleep and the number of nocturnal awakenings significantly increased. The percentage of NREM stage 1 and the number of awakenings increased with age and clinical stage. Paroxysmal epileptiform activity during light sleep (NREM stages 1-2) and high-amplitude delta-wave activity with intermingled sharp waves during slow-wave sleep were characteristic of the recordings. The present study revealed that in patients with JNCL, sleep is consistently altered.

Spectrum of clinical and electrophysiologic features in HNPP patients with the 17p11.2 deletion

OBJECTIVE

To study the clinical and electrophysiologic features of a large series of carriers of the 17p11.2 deletion.

BACKGROUND

The 17p11.2 deletion is associated in most patients with recurrent acute nerve palsies, which is the typical presentation of hereditary neuropathy with liability to pressure palsies (HNPP). Nevertheless, a few other phenotypes have been reported.

METHODS

On the basis of clinical and electrophysiologic data, the authors conducted a retrospective study of 99 individuals with the 17p11.2 deletion referred to their neurogenetic department between 1993 and 1997.

RESULTS

In addition to the typical presentation of HNPP, they describe five other phenotypes in 15 patients: recurrent positional short-term sensory symptoms, progressive mononeuropathy, Charcot-Marie-Tooth disease-like polyneuropathy, chronic sensory polyneuropathy, and chronic inflammatory demyelinating polyneuropathy-like, recurrent subacute polyneuropathy; and 14 asymptomatic patients. In all the deletion carriers, regardless of their phenotype and by the second decade, the authors found a characteristic, multifocal electrophysiologic neuropathy consisting of a diffuse increase in distal motor latencies contrasting with normal or moderately reduced motor nerve conduction velocities, a diffuse reduction in sensory nerve action potential, and multiple focal slowing of nerve conduction at the usual sites of entrapment. The key diagnostic criterion is a bilateral slowing of sensory and motor nerve conduction at the carpal tunnel with at least one abnormal parameter for motor conduction in one peroneal nerve.

CONCLUSION

The authors confirm the clinical phenotypic heterogeneity of the 17p11.2 deletion and suggest that electrophysiologic examination is a reliable tool for screening suspected HNPP patients in its various clinical presentations.

Melatonin ineffective in neuronal ceroid lipofuscinosis patients with fragmented or normal motor activity rhythms recorded by wrist actigraphy

Melatonin was tested as a sleeping pill in five patients with neuronal ceroid lipofuscinoses. The single-blind, placebo-controlled study consisted of motor activity recordings, sleep logs, and administration of placebo or melatonin (2.5 or 5 mg). Daily motor activity rhythms were measured by wrist actigraphy during four 7-day periods (baseline, placebo, melatonin 2.5 mg, and melatonin 5 mg). The placebo or melatonin was administered in the evenings for 3 weeks, and the recordings were made during the last week of the 3-week treatment. Sleep logs were kept by the caregivers during the recordings. Based on period analyses, the activity recordings were evaluated to display a normal (24-h) or fragmented rhythm. Three patients had normal motor activity patterns during the baseline recordings, and administration of placebo or melatonin did not affect their rest/activity rhythms. Two patients had abnormally fragmented activity rhythms during the baseline periods, and administration of placebo or melatonin did not induce synchronization. According to the actigraphic data, there were no changes in activity rhythms resulting from administration of melatonin. However, based on the observations, three families reported that melatonin slightly improved the sleep quality of the patients. These controversial findings show the difficulties involved in specifying the role of melatonin in modulating sleep. Thus, we conclude that more evidence is required before the significance of melatonin as a sleeping pill is defined.

EEG and evoked potentials in infantile neuronal ceroid-lipofuscinosis

Sixteen children with infantile neuronal ceroid-lipofuscinosis (INCL), age range 0.5 to 5.4 years, were studied using EEG, electroretinograms (ERG), visual evoked potentials (VEP) and somatosensory evoked potentials (SEP). Electroencephalography was the first of these examinations to reveal abnormalities, however the EEG may be normal at the preclinical stage. The first abnormality to appear was an attenuated reaction to passive eye opening and closing which was followed by disturbances in background activity and diminution in amplitude, and by disappearance of sleep spindles. The gradual disappearance of posterior rhythm reactivity and of sleep spindles suggests that thalamic dysfunction progresses with time. EEG inactivity appeared by the age of 3 years. Evoked potentials were normal in the early stages of the disease. SEP showed abnormalities at Stage 2 (1.7 years), while ERG and VEP abnormalities appeared at Stage 3 (by the age of 2.5 years). All neurophysiological reactions examined were abolished by the age of 4 years. Follow-up EEG gives important hints as to the early diagnosis of INCL. Progression of the disease can be followed by evoked potentials which may also be helpful in the differential diagnostics.