Objective:To investigate the correlation between macular cherry red spot (CS) and severity of neurological manifestations in Chinese children with sialidosis (SD) type I.Methods:A evidence-based medical study. "China", "Sialidosis" and "Sialidoses" were used as Chinese and English search terms. The literature was searched in CNKI, Wanfang and PubMed. The cases were all from China and matched the diagnostic criteria. According to the presence or absence of CS in the fundus, the SD children were divided into a group with CS (+) and a group without CS (-), and the correlation between the occurrence of ocular CS and neurological manifestations was compared with meta-analysis by RevMan 5.3 software.Results:Sixty-eight studies were initially retrieved according to the search strategy, and 17 studies were finally included, and 5 studies with CS+ and CS- were meta-analyzed. Among the 43 patients, 28 were male and 15 were female, with a median age of 12 years. Visual impairment was observed in 37 cases (90.2%, 37/41, 2 cases not recorded), and CS was present in 24 cases (55.8%, 24/43). The most common neurological manifestation was myoclonus (97.7%, 42/43), followed by cerebellar ataxia (95.1%, 39/41, 2 cases not recorded) and seizures (91.4%, 32/35, 8 cases not recorded). Pathogenic NEU1 gene mutations were detected in 42 cases and one case was undocumented. The incidence of seizure in group CS+ (100%, 20/20) was higher than that in group CS- (80%, 12/15). Meta-analysis showed that there was no statistically significant difference between the incidence of myoclonus or ataxia [relative risk ( RR)=1.13, 95% confidence interval ( CI) 0.79-1.63, P=0.49] and seizure ( RR=1.13, 95% CI 0.84-2.06, P=0.24) among the children in the CS+ and CS- groups. Conclusions:The incidence of ocular CS in Chinese children with type I SD was 55.8%. There was no correlation with neurological manifestations, however the incidence of seizure was significantly higher in patients with CS than in others without CS.

Objective:To summarize the clinical and prognostic features of children with opsoclonus-myoclonus-ataxia syndrome (OMAS).Methods:A total of 46 patients who met the diagnostic criteria of OMAS in the Department of Neurology, Beijing Children′s Hospital from June 2015 to June 2023 were retrospectively analyzed. Centralized online consultations or telephone visits were conducted between June and August 2023. The data of the children during hospitalization and follow-up were collected, including clinical manifestations, assistant examination, treatment and prognosis. According to the presence or absence of tumor, the patients were divided into two groups. The chi-square test or Mann-Whitney U test was used to compare the differences between the two groups. Univariate Logistic regression was used to analyze the factors related to OMAS recurrence and prognosis. Results:There were 46 patients, with 25 males and the onset age of 1.5 (1.2, 2.4) years. Twenty-six (57%) patients were diagnosed with neuroblastoma during the course of the disease, and no patients were categorized into the high-risk group. A total of 36 patients (78%) were followed up for≥6 months, and all of them were treated with first-line therapy with glucocorticoids, gammaglobulin and (or) adrenocorticotrophic hormone. Among the 36 patients, 9 patients (25%) were treated with second-line therapy for ≥3 months, including rituximab or cyclophosphamide, and 17 patients (47%) received chemotherapy related to neuroblastoma. At the follow-up time of 4.2 (2.2, 5.5) years, 10 patients (28%) had relapsed of OMAS. The Mitchell and Pike OMS rating scale score at the final follow-up was 0.5 (0, 2.0). Seven patients (19%) were mildly cognitively behind their peers and 6 patients (17%) were severely behind. Only 1 patient had tumor recurrence during follow-up. The history of vaccination or infection before onset was more common in the non-tumor group than in the tumor group (55%(11/20) vs. 23%(6/26), χ2=4.95, P=0.026). Myoclonus occurred more frequently in the non-tumor group (40%(8/20) vs. 4%(1/26), χ2=7.23, P=0.007) as the onset symptom. Univariate Logistic regression analysis showed that the tumor group had less recurrence ( OR=0.19 (0.04-0.93), P=0.041). The use of second-line therapy or chemotherapy within 6 months of the disease course had a better prognosis ( OR=11.64 (1.27-106.72), P=0.030). Conclusions:OMAS in children mostly starts in early childhood, and about half are combined with neuroblastoma. Neuroblastoma in combination with OMAS usually has a low risk classification and good prognosis. When comparing patients with OMAS with and without tumors, the latter have a more common infection or vaccination triggers, and myoclonus, as the onset symptom, is more common. Early addition of second-line therapy is associated with better prognosis in OMAS.

Objective:To summarize the clinical and genetic characteristics of mental retardation disorder (MRD) with TRIO gene variant in children.Methods:Case series study. The data of 9 children with TRIO gene variants were collected retrospectively from August 2019 to March 2024 in Department of Neurology, Beijing Children′s Hospital, Capital Medical University and Department of Pediatrics, the Third Affiliated Hospital of Zhengzhou University. The data included gender, age, intellectual and motor development, appearance, seizures, neuroimaging and genetic results. The clinical features and genotype-phenotype correlations were summarized.Results:Of the 9 children, 6 boys and 3 girls, 4 MRD63 children presented with moderate to severe developmental delays accompanied by macrocephaly; 5 MRD44 children had mild to moderate developmental delays with microcephaly. A total of 5 children had dysmorphic facial features (flat occiput, thick eyebrows, unibrow, large ears, short fingers, pale skin, yellow hair, and strabismus), 2 children experienced seizures (1 child with myoclonic seizure and 1 with absence seizure), 4 children had feeding difficulties, 1 child had congenital cataracts, 1 child had congenital heart disease, 1 child had recurrent infections, and 1 child had tiger-striped changes in the fundus examination. TRIO gene variants carried by the 9 children were all de novo, involving 8 variant sites, including 7 missense variants and 1 frameshift variant, c.3232C>T/p.R1078W (2 cases), c.3920A>G/p.Y1307C, c.4112A>T/p.H1371L, c.4283G>T/p.R1428L, c.4394A>G/p.N1465S, c.6041T>C/p.I2014T, c.6821G>A/p.R2274H, c.7027delC/p.Q2343Sfs*70. Among them, 2 sites are located in the Spectrin domain, 4 sites are in the GEFD1 domain, 2 sites are in the GEFD2 domain, and 1 site (frameshift variant) is in the PH2-SH3 domain. The individual with frameshift variant exhibit absence seizures, mild developmental delay, and the mildest phenotype. The child with myoclonic seizures was treated with valproic acid and levetiracetam for seizure control, while the child with absence epilepsy was treated with valproic acid and lamotrigine for seizure control. All 9 children underwent regular rehabilitation exercises, making slow progress.Conclusions:TRIO gene related MRD is characterized by varying degrees of developmental delay, and often accompanied by macrocephaly or microcephaly, dysmorphic facial features, and with or without seizures. The main variant types are missense variants, which are mostly concentrated in the Spectran domain and GEFD domain. p. R1078W may be a relative hotspot variant. The phenotype caused by the frameshift variant is relatively milder.

Objective:To investigate the clinical characteristics, laboratory characteristics and genetic diagnosis of aromatic L-amino acid decarboxylase deficiency (AADCD), and to improve the understanding of this disease.Methods:Four children diagnosed with AADCD from the Department of Neurology, Beijing Children′s Hospital Affiliated to Capital Medical University from August 2016 to June 2020 were collected, and their clinical manifestations, laboratory and imaging data, and genetic test results were retrospectively analyzed.Results:All the 4 cases were diagnosed in early infancy, with the first symptom of feeding difficulties. They developed paroxysmal dyspraxia accompanied by eye movement crisis, movement regression, hypotonia, growth retardation, sleep disorders and autonomic nervous symptoms such as ptosis, excessive sweating and nasal congestion at the age of 2-4 months, respectively. The 4 children were siblings from 2 families with healthy parents. The dihydroxyphenylalanine decarboxylase ( DDC) gene mutations in cases 1 and 2 were derived from the maternal missense mutation c.1040G>A(P.RG347gln), and from the paternal deletion of exons 11 and 12, respectively. The DDC gene mutation in case 3 was derived from the maternal mutation c.419G>A(p.G140E) and the paternal mutation c.1375C>T(p.H459Y), respectively. Case 4 did not undergo genetic testing. Blood amino acid and acylcarnitine profiles and urine organic acid analyses were performed in 3 cases, and no specific abnormalities were found. In case 3, the results of 3-O-methyldopa (3-OMD) screening by blood dry filter paper increased significantly. Cerebrospinal fluid neurotransmitter detection results showed that the concentrations of 3-methoxy-4-hydroxyphenyldiol, vanillic acid and 5-hydroxyindoleacetic acid were significantly decreased, while the levels of 5-hydroxytryptophan and 3-OMD were increased in case 3. Blood aromatic L-amino acid decarboxylase (AADC) activity decreased significantly in case 3. Cranial magnetic resonance imaging (MRI) and electroencephalogram (EEG) examinations were performed in cases 1, 3, and 4, among which the cranial MRI in case 1 was normal, while the cranial MRI in cases 3 and 4 suggested that myelination was slightly backward. The EEG was normal in all the 3 cases. Cases 1 and 2 died of pneumonia and respiratory failure at the age of 1 year and 10 months. Case 3 was given clonazepam, benxel hydrochloride tablets and vitamin B6 tablets orally after diagnosis at the age of 4 months, and then treated with selegiline hydrochloride tablets and pramexol hydrochloride tablets. At the follow-up of 1 year and 6 months, the frequency of eye movement crisis and movement disorder was reduced, sleep was improved and autonomic nervous symptoms were alleviated, but there was no improvement in developmental delay. Case 4 was diagnosed with cerebral palsy and epilepsy, but failed various antiepileptic drugs and rehabilitation training, and died at the age of 10 due to heart failure and kidney failure. Conclusions:The clinical manifestations of AADCD are complicated and the misdiagnosis rate is high. Infants with early-onset hypotonia, developmental retardation, eye movement crisis, and movement disorders should be screened with dry filter paper as soon as possible for 3-OMD level, and suspicious cases should be diagnosed by cerebrospinal fluid neurotransmitter detection, plasma AADC activity determination, and gene examination. Early diagnosis of AADCD in children and gene mutation carriers can guide treatment and provide genetic counseling to reduce the incidence of the offspring.

Objective:To describe the clinical features of pediatric biotinase deficiency (BTD) manifested as spinal cord disease.Methods:The clinical data of a child with spinal cord lesions due to biotinase deficiency, diagnosed in Beijing Children′s Hospital in 2020, were collected. The cases with complete clinical data retrieved on literature reported in China National Knowledge Infrastructure, Wanfang Data knowledge Service Platform and PubMed (up to August 2021) by using search terms of biotinase deficiency, pediatric, spinal cord, myelopathy and myelitis were summarized.Results:The patient was a 3 years and 5 months old boy with the main clinical manifestations of subacute progressive limb weakness and wheezing. Physical examination showed sparse hair, rough skin, spastic paraparesis and developmental delay. Cerebrospinal lactic acid was increased (5.67 mmol/L). Cranial magnetic resonance imaging (MRI) showed diffuse T 2/fluid attenuated inversion recovery hyperintensity of the midbrain, dorsal pons, edulla, periacqueductal grey and optic tracts. Spinal cord lesions were extended from the medulla up to the level of the conus. Urineketone bodies and 3-hydroxyisurate were increased. The activity of biotinidase was 0.27 pmol/min (3 mm disc), being 7% of mean normal serum activity. Genetic studies revealed homozygous mutation in the BTD gene [c.284T>A (p.I95N)]. After biotin supplementation for 6 months, the only evident abnormality was residual spasticity of lower limbs. Fourteen English literatures and 2 Chinese literatures including 18 cases were collected. The onset age was from 2 months to 15 years (median age was 4 years). Among them, 11 cases had cranial MRI abnormalities, of which all involved brain stem, 6 cases involved optic tracts and (or) optic chiasm. All 18 cases had spinal cord MRI abnormalities with longitudinally extensive lesion, mostly involved cervical and thoracic spinal segments, and 3 cases involved all spinal segments. Twelve cases received immunotherapy, and 6 were partially improved, 6 were completely invalid. After biotin supplementation, 12 patients had neurological disability. Conclusions:BTD should be included in the differential diagnosis of subacute myelopathy, regardless of the onset age. Early diagnosis and treatment can prevent irreversible neurological damage.

Objective:To summarize the clinical characteristics of children with dystonia 28 (DYT28) caused by KMT2B gene variations so as to improve clinicians′ understanding of the disease. Methods:The clinical manifestations, treatment and gene variation data of 11 children with DYT28 caused by KMT2B gene variations were retrospectively collected and analyzed.The subjects were recruited from the Department of Neurology, Beijing Children′s Hospital, Capital Medical University from March 2018 to January 2021.The patients were followed up. Results:There were 8 males and 3 females.The age at onset was ranging from 1 month to 6 years without inducement.Eight cases were gene-ralized dystonia and 3 cases were multifocal dystonia.The initial symptoms of 7 cases were unilateral or bilateral lower limbs tiptoeing.Four cases presented dysarthria, retching or swallowing difficulties at onset.As the disease progressed, all the cases had laryngeal dystonia, 10 cases had lower limbs dystonia, and 8 cases had upper limbs dystonia.Six cases were complicated with other dyskinesia symptoms.Ten cases had varying degrees of short stature, microcephalus, micrognathia, musculoskeletal abnormalities, intellectual disability, endocrinopathies and sleep difficulties.The brain magnetic resonance imaging showed abnormal in only 1 case.Eleven KMT2B gene pathogenic variants were found, including 8 frameshift variants, 1 in-frame variant and 2 missense variants.Four variants were novel.Eleven cases were followed up at the age of 1 year and 7 months to 17 years and 9 months.One case wasn′t given therapy.The dystonia in 3 cases was mildly improved after medication.Dysfunction of urination and defecation was disappeared in 1 case after medication.The symptom of 6 cases had no improvement after drug therapy.Among the above 6 cases, 5 drug refractory cases had deep brain stimulation, and their dystonia symptoms are all obviously improved; 2 cases had normal control of urination and defecation after deep brain stimulation.The motor scores in the Burke-Fahn-Marsden dystonia rating scale were improved by 55.8%-90.7%, and the disability scores were improved by 14.8%-69.6%. Conclusions:DYT28 caused by KMT2B gene variations is one of the most common and early-onset genetic dystonia in children.The dystonia symptom progresses from local parts to the whole body, prominently involving laryngeal muscles and lower limbs.Control of urination and defecation requires attention.Patients with mild dystonia symptoms can be effectively treated by drugs.However, patients with severe dystonia symptoms were drug refractory, and their dystonia symptoms can be effectively improved by deep brain stimulation.

Objective:To observe and analyze the clinical characteristics and correlation between the eye and nervous system in children with infantile gangliosideosis.Methods:From November 2018 to January 2021, 3 children with infantile ganglion lipidosis diagnosed by genetic examination in the Department of Ophthalmology and Neurology, Beijing Children's Hospital of Capital Medical University, and through China National Knowledge Infrastructure and Wanfang database and The National Library of Medicine of the United States (PubMed) were searched, and 53 cases of Chinese infantile gangliosideosis diagnosed by gene, enzyme activity or pathological examination were selected and a total of 56 cases were included in the study. The searching time was from the establishment of the database to February 2021, and the search keywords are"gangliosideosis", "cherry-spot" macula and "Chinese". The demographic characteristics of 56 cases of children and other system manifestations were analyzed such as eyes, nervous system, skin, bones. According to the presence or absence of cherry-spot (CS) on the fundus examination, the children were divided into a fundus CS group (group A) and a fundus without CS group (group B), with 20 and 27 cases, respectively. The age of onset, gender, different types and neurological manifestations of the two groups of children were compared and analyzed. The non-parametric rank sum test was used for age comparison between groups; the χ2 test or Fisher's exact test were used for the comparison of gender, disease type and incidence between groups. Results:Among the 56 children, 27 were males and 29 were females; the median age of onset was 7.0 months. There were 33 and 23 cases of GM1 and GM2, respectively. Among 44 children with visual function examination records, 41 cases (93.2%, 41/44) were unable to follow the visual object. Of 47 children who underwent ocular fundus examination, 20 cases (42.6%, 20/47) had CS on the fundus. The main manifestations of the nervous system are neuromotor development regression or retardation (100%, 56/56), convulsions (58.1%, 25/43), and "startle" phenomena (89.7%, 26/29). Among 42 patients with brain magnetic resonance imaging examination records, 39 cases (92.9%) were abnormal. The incidence of "startle" and seizures in group A was higher than that in group B, and the difference was statistically significant ( χ2=5.815, 6.182, P=0.021, 0.013). Conclusios:Chinese infantile gangliosideosis is more common in GM1 type. Ocular visual impairment is the visual object as the main manifestation, the incidence of fundus CS is 42.6%, and the symptoms of neurological damage in children with CS are more severe.

Objective:To summarize the clinical characteristics and genetic features of tyrosine hydroxylase deficiency(THD) caused by TH gene variants for the improvement of the understanding of the disease. Methods:The clinical and genetic data of 33 children with THD caused by TH gene variants were diagnosed in the Department of Neurology of Beijing Children′s Hospital, Capital Medical University from May 2011 to January 2020 and their data were retrospectively collected and analyzed. Results:There were 19 females and 14 males.The age at onset was ranged from 0 to 6.3 years.13 patients developed diseases, accompanied with fever after infection, and 1 patient suffered from hypoxia, 19 patients suffered from no predisposing factors.There were 7 mild TH-deficient dopa-responsive dystonia cases, 16 severe TH-deficient infantile parkinsonism with motor delay cases and 10 very severe TH-deficient progressive infantile encephalopathy cases.Clinical symptoms were fluctuating, including 26 cases of diurnal fluctuation, 22 cases of infection aggravation, and 30 cases of fatigue aggravation.The initial symptoms included tiptoeing and numbness in the limbs(7 cases), motor development retardation or degression (26 cases), fremitus (8 cases), ptosis (2 cases), and status dystonicus (3 cases). Other clinical features had hypermyotonia (23 cases), hypomyotonia (27 cases), decreased movement (27 cases), decreased facial expression (24 cases), fremitus (18 cases), tiptoeing (20 cases), talipes equinovarus (7 cases), ptosis (8 cases), oculogyric crisis (10 cases), salivation (21 cases), dysphagia (12 cases), dysarthria (16 cases), dyspnea (3 cases), increased sleep (10 cases), decreased sleep (5 cases), irritable mood (15 cases), apathetic mood (2 cases), profuse sweating (8 cases), and status dystonicus (6 cases). A total of 6 patients′ right limbs were more severe, and 14 patients′ lower limbs were more severe.Eight patients had family history, and Levodopa treatment was effective for all patients.Ten patients suffered side effects, including dyskinesia and irritability.Four patients were lost follow-up, and 29 patients were followed up between 0.8 and 13.2 years old until Ja-nuary 2020.Totally, 22 patients almost had no such symptoms.Twenty-five TH gene pathogenic variants were discovered in 33 patients.There were 13 novel variants (c.1160T>C, c.1303T>C, c.887G>A, c.1084G>A, c.1097A>T, c.734G>T, c.907C>G, c.588G>T, c.992T>G, c.755G>A, c.184-6C>T, c.1510C>T, c.910G>A) and 2 patients had c. 910G>A variant.Meanwhile, there were 5 hot variants [c.698G>A(13 cases), c.457C>T(9 cases), c.739G>A(6 cases), c.1481C>T(4 cases), c.694C>T(3 cases)]. c.910G>A(2 cases) may be the foun-der variant of Chinese population. Conclusions:THD caused by TH gene variant mostly onsets from infant, with complex clinical features.Most of these patients were severe, and only a few were very severe and mild.Very severe and mild symptoms were easily misdiagnosed.Levodopa treatment was obviously effective.A possible founder variant of Chinese population (c.910G>A) was found.c.698G>A and c. 457C>T mutations mainly appeared in patients with severe and extremely severe THD, while c. 739G>A mainly appeared in patients with mild THD.

Objective:To investigate the clinical features and prognosis of pediatric autoimmune encephalitis associated with anti-glutamic acid decarboxylase 65 (GAD65) antibody.Methods:Clinical data of 2 patients diagnosed as autoimmune encephalitis associated with anti-GAD65 antibody at Department of Neurology, Beijing Children′s Hospital in 2019 were analyzed retrospectively. A literature search with “anti-GAD65 antibody”“encephalitis”“epilepsy” or “cerebellar ataxia” as key words was conducted at China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform and PubMed (up to January 2020). The clinical features and prognosis of pediatric cases with complete clinical data were retrieved and summarized.Results:Two patients with positive anti-GAD65 antibody of serum and cerebrospinal fluid were both females. The onset age of case 1 was 57 months and her main clinical manifestations were fever and unconsciousness. The cranial magnetic resonance imaging (MRI) showed diffuse T2 weighted imaging (T2WI) abnormal signals, and the electroencephalogram (EEG) showed slow waves. The onset age of case 2 was 80 months and her main clinical manifestations of were recurrent focal seizures, memory loss, and headache. The MRI showed high T2WI signal in bilateral hippocampus, and the EEG showed abnormal discharge involving the temporal area. Both cases were treated with methylprednisolone and intravenous immunoglobulin, the short-term symptoms of them were both improved. They were followed up for 6 months and 1 year respectively, the case 1 recovered completely, and the case 2 still had focal seizures. Six English reports which included 6 cases were retrieved. Together with these 2 cases, a total of 8 cases were analyzed. The clinical symptoms included seizures (6 cases), memory loss (4 cases), loss of consciousness (3 cases), behavioral abnormalities (3 cases), cognitive impairment (2 cases), headache (2 cases), autonomic symptoms (1 case), ataxia (1 case), dysphagia (1 case), and aphasia (1 case). There were 5 cases with cranial MRI abnormalities in the acute phase or sub-acute phase, of whom 3 cases had the limbic system involvement, and 2 cases were mainly had extra limbic area involvement. Three cases had hippocampal atrophy or sclerosis during follow-up. All 8 patients were treated with immunotherapy. After immunotherapy, all patients had short-term improvement. Follow-up for 6 months to 6 years showed that 3 cases with extra limbic encephalitis improved to baseline levels, and 5 limbic encephalitis cases had poor outcomes, including 1 death and 4 cases still had focal epilepsy.Conclusions:Pediatric anti-GAD65 antibody associated autoimmune encephalitis is a rare but treatable disease, including limbic encephalitis and extra limbic encephalitis. The most common clinical manifestations are seizures and memory impairment. Early diagnosis and immunotherapy can improve the symptoms in a short time. But patients with limbic encephalitis often had refractory epilepsy in the chronic phase, and have a poor long-term outcome.

Objective:To summarize the clinical characteristics of SYNGAP1-related epilepsy in children.Methods:Data of 13 patients with SYNGAP1 gene variants diagnosed with epilepsy at Department of Neurology, Beijing Children's Hospital were collected retrospectively from March 2017 to October 2020 and the patients were followed up. The clinical features, electroencephalogram(EEG), brain imaging, gene results and treatment were summarized.Results:Twelve patients were followed up successfully among the 13 patients with SYNGAP1 variants. The last follow-up age was 5 years and 7 months (3 years and 1 month to 9 years).The onset age of seizures was 2 years (4 months to 3 years). Seizure types included eyelid myoclonia with or without absence (9 cases), myoclonic seizure (5 cases), atypical absence (4 cases), suspicious atonic seizures(4 cases),unclassified fall attack (6 cases), and the frequency of seizures varied from several times to more than 100 times per day. Four cases had the mimic phenotype of myoclonic astatic epilepsy. The seizures of 10 cases could be triggered by eating (5 cases), emotion (5 cases), fever (3 cases), voice (2 cases), fatigue (2 cases), etc. Electroencephalography (10 cases) showed interictal generalized or focal epileptiform discharges (9 cases), and atypical aphasia (4 cases), myoclonic seizure (2 cases) and eyelid myoclonic seizure (1 case) were monitored. Of the 12 cases, 9 were added with valproate, all of which were effective (the frequency of seizures reduced>50%). Five cases received combined levetiracetam, in 3 the treatments were effective. To last follow-up, 3 cases were seizure free from 6 months to 1 year and 1 month, but the remaining 7 cases still had seizures, one or several times per day. All 13 cases had developmental retardation (speech ability impaired mostly), 2 cases were severe, 10 cases were moderate, 1 case was mild. The SYNGAP1 gene variants of 13 patients were all de novo, including 12 variants. Among them, 4 were frameshift variants, 4 were nonsense variants, 2 were missense variants and 2 were splice site variants.Conclusions:Patients with SYNGAP1-related epilepsy have an early onset age and many seizure types. The main seizure type is eyelid myoclonia with or without absence, and other seizure types include myoclonic seizure, atypical absence, unclassified fall attack, etc. Valproate is effective in most patients, but seizures in some patients might be intractable. Most patients have developmental delay (mainly moderate and severe), speech ability impaired mostly.