General low alertness in people with obstructive sleep apnea.

STUDY OBJECTIVES: In patients with obstructive sleep apnea (OSA), a previous study using a Go/No-Go task reported an average attention deficit. However, the temporal dynamics of such a deficit are unknown. Here, we investigated whether attention deficits in different subdomains increased as the test progressed. We also investigated the effect of target frequency and speed of stimulus presentation on performance. METHODS: Twenty-seven untreated people with OSA and 27 age- and sex-matched controls underwent a 15-minute Go/No-Go task, divided into 6 blocks. Each block was subdivided into 3 different interstimulus intervals (1, 2, and 4 seconds). Three blocks had a low and three had a high target probability (20% and 80%, respectively). Reaction time (alertness), variability of reaction time (sustained attention), commission errors (response inhibition), and omission errors (focused attention) were measured. RESULTS: Alertness was lower in the group with OSA compared with controls, as evidenced by a significantly higher average reaction time. This effect was seen from the start of the task and continued until the end but did not increase in test progression. The temporal pattern of intrinsic alertness deficits in patients with OSA was found to be independent of target frequency or interstimulus interval. CONCLUSIONS: The primary attention problem in OSA is on the alertness subdomain irrespective of the number of required responses or speed of stimulus presentation. The present results support the notion that OSA is distinct from other neurological and psychiatric conditions, such as depression or chronic pain. The results also suggest significant concerns regarding daily life activities (eg, driving). CITATION: de Souza Bezerra ML, van Duinkerken E, Simões E, Schmidt SL. General low alertness in people with obstructive sleep apnea. J Clin Sleep Med. 2024;20(5):689-698.

The Role of Visual and Auditory Stimuli in Continuous Performance Tests: Differential Effects on Children With ADHD.

Objective: Continuous performance tests (CPTs) usually utilize visual stimuli. A previous investigation showed that inattention is partially independent of modality, but response inhibition is modality-specific. Here we aimed to compare performance on visual and auditory CPTs in ADHD and in healthy controls. Method: The sample consisted of 160 elementary and high school students (43 ADHD, 117 controls). For each sensory modality, five variables were extracted: commission errors (CEs) and omission errors (OEs), reaction time (RT), variability of reaction time (VRT), and coefficient of variability (CofV = VRT / RT). Results: The ADHD group exhibited higher rates for all test variables. The discriminant analysis indicated that auditory OE was the most reliable variable for discriminating between groups, followed by visual CE, auditory CE, and auditory CofV. Discriminant equation classified ADHD with 76.3% accuracy. Conclusion: Auditory parameters in the inattention domain (OE and VRT) can discriminate ADHD from controls. For the hyperactive/impulsive domain (CE), the two modalities are equally important.

A serial SPECT-CT study in a celiac disease patient with cerebellar ataxia and psychiatric symptoms.

Celiac disease (CD) is an immune-mediated systemic disorder triggered by gluten and related prolamins in genetically predisposed individuals. Here, we described a case of a 31-year-old Caucasian woman who exhibited cerebellar and psychiatric dysfunctions. The patient underwent single-photon emission computed tomography (SPECT-CT) before and after a gluten-free diet (GFD). There was an improvement in cerebellar perfusion accompanied by a remission of cerebellar manifestations. The maintenance of the psychiatric manifestations was related to the persistence of the hypoperfusion in the frontal lobes. The patient's psychiatric symptoms did not change after 4 months under a GFD in the hospital. To our knowledge, this is the first case that shows the relationship between improvement in cerebellar perfusion and remission of cerebellar clinical manifestations in a CD patient under a GFD.

Decrease in Attentional Performance After Repeated Bouts of High Intensity Exercise in Association-Football Referees and Assistant Referees.

Referees and assistant referees are submitted to high physical stress during matches. Pressure to make decisions in front of large crowds is another potential stressor. These two stressors can impair attention executive control, depending on physical fitness and individual vulnerability or resilience to situational pressure. Error percentage for referees and assistants may reach around 14% during a soccer match. Although previous studies have suggested that soccer referees and assistants should take cognitive assessments, they are only required by Fédération Internationale de Football Association (FIFA) to demonstrate knowledge of the rules and pass annually in a fitness test (FIFA-Test). This study aimed to assess attention performance in referees and assistants before and after the mandatory FIFA-Test. It is hypothesized that the high physical demands associated with the pressure to pass the FIFA-Test would interfere with attention performance. The sample included 33 referees and 20 assistants. The Continuous Visual Attention Test (CVAT) consisted of a 15-min Go/No-go task. Performance in the CVAT is based on four variables: omission and commission errors, reaction time, and variability of reaction time (VRT). Failure in the CVAT was defined by a performance below the 5th percentile of the age- and sex-matched normative data in at least one variable of the CVAT. Before the FIFA-Test all participants performed the CVAT. The second CVAT began 3-7 min directly following completion of the FIFA-test. Considering only the officials who passed both the FIFA-Test and the first CVAT (19 referees and 15 assistants), 44% (9 referees and 6 assistants) exhibited a performance decline in the second CVAT. A significant increase in VRT was found after the high intensity exercise. As increase in VRT is thought to reflect executive dysfunctions and lapses of attention, we concluded that physical fitness alone may not be enough to help officials cope with the physical and contextual stresses associated with the FIFA-Test. These data suggest that over 35% of soccer referees and their assistants who were considered physically able to referee matches may not be mentally prepared for the attentional demands of refereeing soccer matches.

Association Between Auditory and Visual Continuous Performance Tests in Students With ADHD.

OBJECTIVE: Continuous Performance Tests (CPTs) are known to measure inattention and impulsivity in students with ADHD. Many CPTs utilize a visual format. It is accepted that auditory tasks reflect attentional demand more closely in the classroom. Thus, the association between deficits found by auditory and visual CPTs needs to be studied. We hypothesized that impulsivity would be dependent on sensory modality and inattention would be a unitary cross-modal construct. METHOD: Forty-four students with ADHD performed two CPTs (visual and auditory). We analyzed correlations between the variables examined by the two tasks. RESULTS: There were strong correlations between variables measuring inattention. Correlations between auditory and visual measures of impulsivity were weak. CONCLUSION: Inattention is partially independent of modality. In contrast, response inhibition is modality-specific. Although ADHD is defined regardless of modality, hyperactive students may exhibit deficits in the auditory modality but not in the visual modality or vice versa.

Analysis of Attention Subdomains in Obstructive Sleep Apnea Patients.

Background: Obstructive sleep apnea (OSA) is characterized by apnea-hypopnea during sleep. Overnight polysomnography (PSG) is usually used to detect the frequency of apneic and hypopneic events. Attention and executive deficits are commonly reported in OSA patients. Previous investigations suggested that cognitive impairments were dependent on attention deficits. However, attention is not a unitary domain and consists of different subdomains such as alertness, sustained attention, focused attention, and executive attention (impulsivity/hyperactivity). Little is known about the attention subdomains affected in OSA. Attention is commonly assessed using continuous performance tests, such as the continuous visual attention test (CVAT). Distinct variables can be derived from the CVAT. Each CVAT variable is associated with a specific attention subdomain. Objective: This study aimed to examine the variables of the CVAT that are affected by OSA and to identify the most reliable CVAT variable that distinguishes OSA from controls via discriminant analysis. Method: Patients scheduled to perform a PSG were invited to participate in this study. Immediately before the PSG, they performed the CVAT. Based on the PSG results, 27 treatment-naïve OSA patients were sampled. The same number of healthy controls were selected to match the two groups by age and gender. Five CVAT variables were examined: commission errors, omission errors, reaction time (RT), variability of reaction time (VRT), and coefficient of variability (VRT/RT). Results: ANCOVAs indicated that RT and VRT were affected by OSA. No difference in accuracy (omission and commission errors) was observed between healthy controls and OSA patients. When the VRT measurements were corrected for their respective RT values (VRT/RT), the mean difference on this coefficient did not reach significance. The discriminant analysis indicated that the two groups could be best differentiated by the RT variable. Conclusions: Attention problems, commonly observed in OSA patients, may reflect a primary problem on the alertness subdomain. The CVAT was able to detect the primary (alertness-RT parameter) and the secondary deficits (sustained attention-VRT parameter) associated with OSA. As there is no learning effect in the condition of retests, the CVAT can be used to assess the cognitive recovery in OSA patients during treatment.

Effect of handedness on auditory attentional performance in ADHD students.

The relationship between handedness and attentional performance is poorly understood. Continuous performance tests (CPTs) using visual stimuli are commonly used to assess subjects suffering from attention deficit hyperactivity disorder (ADHD). However, auditory CPTs are considered more useful than visual ones to evaluate classroom attentional problems. A previous study reported that there was a significant effect of handedness on students' performance on a visual CPT. Here, we examined whether handedness would also affect CPT performance using only auditory stimuli. From an initial sample of 337 students, 11 matched pairs were selected. Repeated ANOVAs showed a significant effect of handedness on attentional performance that was exhibited even in the control group. Left-handers made more commission errors than right-handers. The results were interpreted considering that the association between ADHD and handedness reflects that consistent left-handers are less lateralized and have decreased interhemispheric connections. Auditory attentional data suggest that left-handers have problems in the impulsive/hyperactivity domain. In ADHD, clinical therapeutics and rehabilitation must take handedness into account because consistent sinistrals are more impulsive than dextrals.

What does handedness reveal about ADHD? An analysis based on CPT performance.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder. Continuous performance Tests (CPTs) aid the diagnosis. Handedness is linked to disabilities. OBJECTIVES: 1-To study the association between handedness and ADHD; 2-To verify the usefulness of the CPT in school settings; 3-To exam the relationship between handedness and CPT performance. METHOD: Each child was classified as right-consistent, left-consistent, or non-consistent. From the sample, 171 controls and 68 ADHDs fulfilled the inclusion criteria. The effect of handedness on the CPT was studied using a paired-sample that matched handedness by age, grade, gender, and ADHD. RESULTS: Left-handed students had a probability of suffering from ADHD 2.88 greater than right-handers. ANOVAs on standardized scores indicated that the ADHD students exhibited higher number of errors and higher variability of reaction times as compared to the controls. Discriminant analysis indicated that these CPT parameters could discriminate ADHD from controls. Repeated ANOVAs showed a significant effect of handedness on commission errors (CE) because left-handers made more CEs than right-handers. CONCLUSIONS: 1-The association between ADHD and handedness reflects that left-handers are less lateralized and have decreased interhemispheric connections; 2-The CPT can be used to measure different attention domains in school settings; 3- Left-handers have problems in the impulsive/hyperactivity domain.

Cholangiocarcinoma associated with limbic encephalitis and early cerebral abnormalities detected by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography: a case report.

BACKGROUND: Limbic encephalitis was originally described as a rare clinical neuropathological entity involving seizures and neuropsychological disturbances. In this report, we describe cerebral patterns visualized by positron emission tomography in a patient with limbic encephalitis and cholangiocarcinoma. To our knowledge, there is no other description in the literature of cerebral positron emission tomography findings in the setting of limbic encephalitis and subsequent diagnosis of cholangiocarcinoma. CASE PRESENTATION: We describe a case of a 77-year-old Caucasian man who exhibited persistent cognitive changes 2 years before his death. A cerebral scan obtained at that time by 2-deoxy-2-[fluorine-18]fluoro- D -glucose integrated with computed tomography-positron emission tomography showed low radiotracer uptake in the frontal and temporal lobes. Cerebrospinal fluid analysis indicated the presence of voltage-gated potassium channel antibodies. Three months before the patient's death, a lymph node biopsy indicated a cholangiocarcinoma, and a new cerebral scan obtained by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography showed an increment in the severity of metabolic deficit in the frontal and parietal lobes, as well as hypometabolism involving the temporal lobes. Two months before the patient's death, cerebral metastases were detected on a contrast-enhanced computed tomographic scan. Postmortem examination revealed a cholangiocarcinoma with multiple metastases including the lungs and lymph nodes. The patient's brain weighed 1300 g, and mild cortical atrophy, ex vacuo dilation of the ventricles, and mild focal thickening of the cerebellar leptomeninges, which were infiltrated by neoplastic epithelial cells, were observed. CONCLUSIONS: These findings support the need for continued vigilance in malignancy surveillance in patients with limbic encephalitis and early cerebral positron emission tomographic scan abnormalities. The difficulty in early diagnosis of small tumors, such as a cholangiocarcinoma, is discussed in the context of the clinical utility of early cerebral hypometabolism detected by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography in patients with rapidly progressive dementia.