Balancing the 2 Hemispheres in Simple Calculation: Evidence From Direct Cortical Electrostimulation.

How do the parietal lobes contribute to simple calculation? Clinical and neuroimaging methods, which are based mainly on correlational evidence, have provided contrasting results so far. Here we used direct cortical electrostimulation during brain surgery to causally infer the role of the left and right parietal lobes in simple calculation. Stimulation provoked errors for addition and multiplication in different parietal areas on both hemispheres. Crucially, an innovative qualitative error analysis unveiled the functional contrast of the 2 parietal lobes. Right or left stimulation led to different types of substitution errors in multiplication, unveiling the function of the more active hemisphere. While inhibition of the left hemisphere led mainly to approximation errors, right hemisphere inhibition enhanced retrieval within a stored repertory. These results highlight the respective roles of each hemisphere in the network: rote retrieval of possible solutions by the left parietal areas and approximation to the correct solution by the right hemisphere. The bilateral orchestration between these functions guarantees precise calculation.

TMS of supplementary motor area (SMA) facilitates mental rotation performance: Evidence for sequence processing in SMA.

In the present study we applied online transcranial magnetic stimulation (TMS) bursts at 10Hz to the supplementary motor area (SMA) and primary motor cortex to test whether these regions are causally involved in mental rotation. Furthermore, in order to investigate what is the specific role played by SMA and primary motor cortex, two mental rotation tasks were used, which included pictures of hands and abstract objects, respectively. While primary motor cortex stimulation did not affect mental rotation performance, SMA stimulation improved the performance in the task with object stimuli, and only for the pairs of stimuli that had higher angular disparity between each other (i.e., 100° and 150°). The finding that the effect of SMA stimulation was modulated by the amount of spatial orientation information indicates that SMA is causally involved in the very act of mental rotation. More specifically, we propose that SMA mediates domain-general sequence processes, likely required to accumulate and integrate information that are, in this context, spatial. The possible physiological mechanisms underlying the facilitation of performance due to SMA stimulation are discussed.

Numerical activities of daily living in adults with neurofibromatosis type 1.

BACKGROUND: This study aimed to identify the mathematical domains affected in adults with neurofibromatosis 1 (NF1) and the impact of the numerical difficulties on the patients' activities of daily living. METHODS: We assessed 28 adult patients with NF1 and 28 healthy control participants. All participants completed the standardised battery of numerical activities of daily living along with clinical batteries of cognitive (Mini-Mental State Examination) and daily functioning (instrumental activities of daily living). The group comparisons of the performance on numerical activities of daily living were carried out using t-test correcting for multiple comparisons. RESULTS: The results showed that the NF1 group performed worse than controls in written subtractions, written multiplication, multiplication principles and digit comprehension (dot counting) tasks. Importantly, no significant differences in numerical ecological tasks were found between patients and controls, suggesting a possible use of compensatory strategies in daily living abilities in spite of calculation deficits. CONCLUSION: The findings indicate that NF1 affects calculation but not the basic comprehension or representation of numbers in adult patients. These data have important implications for designing cognitive interventions tailored to the cognitive profile of individuals with NF1.

Experiences from the implementation of physical therapy via telehealth for individuals with Parkinson disease during the COVID-19 pandemic.

PURPOSE: To (1) determine the characteristics and participation rate of adults with Parkinson disease (PD) in physical therapy (PT) delivered via telehealth, (2) identify the outcome measures and interventions implemented, (3) determine the safety of and (4) patient and therapist satisfaction with PT via telehealth in a clinic specializing in the care of people with PD during the coronavirus pandemic. MATERIALS & METHODS: A retrospective analysis of PT services via telehealth was conducted. Participating patients completed a satisfaction survey. Physical therapists (PTs) who delivered this care were interviewed. Three coders conducted thematic analysis of interviews. Descriptive statistics described the participation rate, demographics, outcome measures, interventions, and safety. RESULTS: There was a 71.4% participation rate. Participants (n = 55) were white (96%), non-Hispanic (100%), older adult (mean = 69.5 years (8.3)) males (65.5%). Non-participants (n = 22) had similar demographics. Therapists selected patient-reported measures more often than performance-based measures. Therapeutic exercise was the most common intervention. All patients (80% response rate) reported satisfaction with their experience. PTs reported the home enhanced specificity of training but impeded evaluation. Therapists endorsed a hybrid model for future practice. CONCLUSIONS: Patients reported satisfaction with PT via telehealth during the pandemic. A hybrid model may support optimal delivery of PT.IMPLICATIONS FOR REHABILITATIONPhysical therapy via telehealth for patients with Parkinson disease was acceptable to patients and physical therapists in our study.Physical therapy via telehealth was safe for people with Parkinson disease in our study, although availability and benefits may not be reaching all populations equitably.Both physical therapists and patients endorse a hybrid model of care (a combination of in-person and remote assessment and treatment) to profit from the strengths of in-person and virtual formats while minimizing barriers to access.

Prism adaptation in patients with unilateral lesion of the parietal or cerebellar cortex: A pilot study on two single cases using a concurrent exposure procedure.

Neuroimaging studies showed that prism adaptation (PA), a widely used tool for the rehabilitation of neglect, involves a wide network of brain regions including the parietal cortex and the cerebellum. In particular, the parietal cortex has been suggested to mediate the initial stage of PA through conscious compensatory mechanisms as a reaction to the deviation induced by PA. The cerebellum, on the other side, intervenes in sensory errors prediction to update internal models in later stages. It has been suggested that two mechanisms may underlie PA effects: recalibration, a strategic cognitive process occurring in the initial stages of PA, and realignment, a fully automatic reorganization of spatial maps emerging later and more slowly in time. The parietal lobe has been proposed to be involved mainly in the recalibration whereas the realignment would be carried over by the cerebellum. Previous studies have investigated the effects of a lesion involving either the cerebellum or the parietal lobe in PA taking into account both realignment and recalibration processes. Conversely, no studies have compared the performance of a patient with a cerebellar lesion to that of a patient with a parietal lesion. In the present study, we used a recently developed technique for digital PA to test for differences in visuomotor learning after a single session of PA in a patient with parietal and a patient with cerebellar lesions, respectively. The PA procedure, in this case, includes a digital pointing task based on a concurrent exposure technique, which allows patients to fully see their arm during the pointing task. This procedure has been shown to be as effective as the terminal exposure condition in neglect rehabilitation albeit different processes take place during concurrent exposure condition compared to the most used terminal exposure (allowing to see only the final part of the movement). Patients' performances were compared to that of a control group. A single session of PA was administered to 1) a patient (BC) with left parieto-occipital lesion involving superior parietal lobe (SPL) and inferior parietal lobe (IPL), 2) a patient (TGM) with a stroke in the territory sub-served by the superior cerebellar artery (SCA) , and 3) 14 healthy controls (HC). The task included three conditions: before wearing prismatic goggles (pre-exposure), while wearing prisms (exposure) and after removing the goggles (post-exposure). Mean deviations were calculated for the following phases: pre-exposure, early-exposure, late-exposure, post-exposure. The presence of after-effect was calculated as the difference between pre-exposure and post-exposure conditions. For each of these conditions, patients' performance was compared to that of the control group by using a modified Crawford t-test. We found that the patient with the parietal lesion had a significantly different performance in the late-exposure and in the post-exposure compared to both HC and the patient with the cerebellar lesion. Conversely, no differences were observed between TGM and HC across all the conditions. Our results show an increase in the magnitude of the adaptation during the late stage of PA in the patient with the parietal lesion whereas no differences in the performance between the cerebellar patient and the controls were found. These results confirm previous studies suggesting that the parietal cortex is an important node of a wider network involved in PA effect. Furthermore, results concerning the cerebellar patient suggest that visuomotor learning is not affected by lesions of the SCA territory when a concurrent exposure is used as, in such case, it less relies on sensory errors prediction to update internal models. Results are discussed considering the novelty of the applied PA technique.

Magnetoencephalography reveals differences in brain activations for fast and slow responses to simple multiplications.

Despite decades of studies, it is still an open question on how and where simple multiplications are solved by the brain. This fragmented picture is mostly related to the different tasks employed. While in neuropsychological studies patients are asked to perform and report simple oral calculations, neuroimaging and neurophysiological studies often use verification tasks, in which the result is shown, and the participant must verify the correctness. This MEG study aims to unify the sources of evidence, investigating how brain activation unfolds in time using a single-digit multiplication production task. We compared the participants' brain activity-focusing on the parietal lobes-based on response efficiency, dividing their responses in fast and slow. Results showed higher activation for fast, as compared to slow, responses in the left angular gyrus starting after the first operand, and in the right supramarginal gyrus only after the second operand. A whole-brain analysis showed that fast responses had higher activation in the right dorsolateral prefrontal cortex. We show a timing difference of both hemispheres during simple multiplications. Results suggest that while the left parietal lobe may allow an initial retrieval of several possible solutions, the right one may be engaged later, helping to identify the solution based on magnitude checking.

Sleep disorders and cognitive dysfunction in acromegaly.

PURPOSE: In the general population, sleep disorders are associated with an increased risk of cognitive impairment. The prevalence of sleep disorders, such as sleep apnea, in acromegalic patients is higher than in the general population, and they may have additional risk of cognitive impairment due to acromegaly treatment and comorbidities. We aim to study the relationship between sleep disturbances and cognitive dysfunction in a group of acromegalic patients. METHODS: We studied 67 consecutive acromegalic patients. We performed a neurocognitive assessment and patients completed the Acromegaly Quality of Life Questionnaire (AcroQoL), Epworth Sleepiness Scale, and Pittsburgh Sleep Quality Index. RESULTS: Of the 67 acromegaly patients in the study, 38.8% were male and median age at the neurological examination was 56 (IQR 48, 65). Approximately 6-10% of patients had impaired cognitive assessment, depending on the test. In linear regression models adjusted for age, sex, BMI, disease duration, and disease activity, poorer sleep quality was associated with lower global cognitive z-score (B = -0.03, 95% CI -0.06, -0.002). Daytime somnolence was associated with poorer physical AcroQoL sub-score (B = -0.04, 95% CI -0.08, -0.002). Sleep quality was associated with poorer overall AcroQoL (B = -0.03, 95% CI -0.05, -0.006), physical AcroQoL (B = -0.04, 95% CI -0.07, -0.005), psychological AcroQoL (B = -0.02, 95% CI -0.04, -0.001), and social AcroQoL (B = -0.02, 95% CI -0.04, -0.0009). CONCLUSIONS: In acromegaly patients, we found robust evidence that poor sleep quality is associated with poorer quality of life, and some evidence that it is associated with poorer cognitive function.

Re-assessing acalculia: Distinguishing spatial and purely arithmetical deficits in right-hemisphere damaged patients.

Arithmetical deficits in right-hemisphere damaged patients have been traditionally considered secondary to visuo-spatial impairments, although the exact relationship between the two deficits has rarely been assessed. The present study implemented a voxelwise lesion analysis among 30 right-hemisphere damaged patients and a controlled, matched-sample, cross-sectional analysis with 35 cognitively normal controls regressing three composite cognitive measures on standardized numerical measures. The results showed that patients and controls significantly differ in Number comprehension, Transcoding, and Written operations, particularly subtractions and multiplications. The percentage of patients performing below the cutoffs ranged between 27% and 47% across these tasks. Spatial errors were associated with extensive lesions in fronto-temporo-parietal regions -which frequently lead to neglect- whereas pure arithmetical errors appeared related to more confined lesions in the right angular gyrus and its proximity. Stepwise regression models consistently revealed that spatial errors were primarily predicted by composite measures of visuo-spatial attention/neglect and representational abilities. Conversely, specific errors of arithmetic nature linked to representational abilities only. Crucially, the proportion of arithmetical errors (ranging from 65% to 100% across tasks) was higher than that of spatial ones. These findings thus suggest that unilateral right hemisphere lesions can directly affect core numerical/arithmetical processes, and that right-hemisphere acalculia is not only ascribable to visuo-spatial deficits as traditionally thought.

Decision-making in obesity: a study using the Gambling Task.

The present study addresses the issue of whether a "decision-making disorder" could account for the behavioral problems of severely obese patients (BMI score >34) who are not classified by traditional psychiatric Eating Disorder tests. The neuropsychological test employed, the Gambling Task (GT), is not directly related to the food domain, but it is sensitive to failure in making long-term advantageous choices. A comparison was made of 20 obese subjects (OS) and 20 normal-weight subjects (NWS) matched in age, education and IQ. The subjects' personalities and food behavior were assessed from psychological questionnaires, and then the Gambling Task was administered. The number of "good" choices made by the two groups during GT performance differed significantly, and the OS did not learn to maximize advantageous choices like the NWS did. OS behavior could be consistent with a prefrontal cortex defect that implies difficulties in inhibition of excessive food intake.

Localization of body parts in brain injured subjects.

The issues which were dealt with in this study were whether the determinants of failure in body part identification differed as a function of modality of stimulus presentation or as a function of response conditions, and whether such differences could be attributed to neurologically determined variables, or to a generalized disorder of awareness of body topology. No evidence was found to support any of these latter factors as an explanation for impaired body part identification. Rather it can be concluded that a common factor underlies success in identifying body parts under all conditions and that this factor is the strength and precision of the conceptual representation of individual body parts.

Generating visual mental images: deficit after brain damage.

This is the first non-retrospective neuropsychological group study using a componential task analysis for the study of imagery. Seventy unilaterally brain damaged patients were tested on a series of tasks with the intent of isolating genuine deficits of the image generation process. The main finding is that the image generation seems to be more frequently disturbed after a left posterior damage. Suggestions are provided for further investigations.

The grammatical properties of mass nouns: an aphasia case study.

A patient (F.A.) is described who, as a consequence of brain damage, shows an isolated deficit concerning the use, across a series of tasks, of the grammatical properties of mass/non-countable nouns. Her use of grammar is otherwise perfect. This behaviour dissociates from that of other patients who have severe grammatical difficulties, but do not show any impairment in the mass nouns tasks that F.A. fails. This case is thought to demonstrate how specific grammatical rules, that are said to be stored at the lemma level of lexical retrieval, are indeed independently represented and accessible.

Hemispheric specialization for sign language.

Most studies on sign lateralization provide inconclusive results about the role of the two hemispheres in sign language processing, whereas the cases reported in the clinical literature show sign language impairment only following left hemisphere damage, suggesting a similar neural organization to spoken languages. By discriminating different levels of processing, a tachistoscopic study found that in deaf subjects matches of sign language handshapes based on equivalence of meaning are processed faster in the right visual field, thus demonstrating a left hemisphere superiority.

Word formation: new evidence from aphasia.

Three aphasic patients are described whose speech contains invented word-forms which are legal combinations of meaningful parts of real words, like "fratellismo" (brother + ness) instead of "fratellanza" (brother + hood), and from combinations of meaningless and meaningful parts, like "terness + ico" (where "ico" is a real adjectival ending). These phenomena are previously unreported. On the assumption that brain-damaged patients use residual rather than novel abilities, these forms, along with the patients' predominant use of real compound words, indicate that speakers have a procedure for composing polymorphemic words online, but this is employed just when trying to find a whole word fails.

Impaired grating discrimination following right hemisphere damage.

We investigated the effect of unilateral brain lesions on visual discrimination of low-, middle- and high-frequency gratings. The performance of patients with right hemisphere lesions was significantly impaired compared with that of both controls and patients with left hemisphere lesions. This impairment was largely limited to patients with right posterior hemispheric lesions and was present with all spatial frequencies. These findings run counter to the hypothesis that high and low spatial frequencies are preferentially processed by different hemispheres.

The role of the right hemisphere in processing negative sentences in context.

Given a pattern consisting of x1, x2,..., xn similar elements and y1, which is perceived as different from the former, it is more plausible to assert that y is not x rather than to assert that x is not y (Wason, J. verb. Learn verb. Behav. 4, 7-11, 1965). In order to appreciate such a difference, the entire set has to be considered. Right-hemisphere brain-damaged patients were submitted to a series of visually presented patterns, each pattern consisting of seven similar items and one dissimilar item. Their task was to complete a statement referring to a single element of each pattern. Statements were either simple affirmative or negative sentences. Errors and reaction times were recorded. Patients with a right-hemisphere injury were found to be insensitive to the plausible-implausible dimension in completing negative sentences. It is hypothesized that right-hemisphere brain-damaged patients are less adequate in this task because they are less capable in putting each element into the visual context.

Anomia for people's names.

The case of an anomia for people's names is reported. The study of this dissociation helps to clarify the difference in processing between proper and common names. Associated deficits in this and previously described cases provide support for the idea that an inability to retrieve arbitrary relations is the basis of the naming difficulty. This would confirm the role of proper names as purely referring expressions.

Anomia for people names in DAT--evidence for semantic and post-semantic impairments.

Proper name anomia is a frequent finding among patients in the early stages of Alzheimer's disease. The present study investigates naming of famous persons in a group of DAT patients, a group of persons with mild cognitive impairment (MCI) and healthy controls. The study is aimed at distinguishing the relative contributions of semantic and post-semantic factors to difficulties in proper name retrieval. As shown by a significantly lower score in answering semantic questions, DAT patients retrieve less biographical knowledge related to famous persons than healthy elderly subjects and persons with mild cognitive impairment. This finding is in line with the frequent observation of semantic deficits in early and moderate DAT. The high number of Tip-of-the-Tongue (TOT) answers in DAT found in relation to few spontaneously named items shows that post-semantic deficits are as important as semantic deficits in determining anomia for people names in DAT. Moreover, DAT patients were less sensitive to phonological cueing than healthy persons or persons with mild cognitive impairment. These findings suggest that proper name anomia in DAT is not only due to semantic deficits, but also to problems in accessing the phonological representation, as well as to a degradation of phonological representations. Thus, naming deficits in DAT differ not only quantitatively, but also qualitatively from the difficulties of healthy elderly persons. No significant differences were found between persons with mild cognitive impairment and healthy controls in proper name retrieval.

Study of the temporal variables in the spontaneous speech of three neologistic jargonaphasics.

Hesitation analysis of spontaneous production from three neologistic jargonaphasics is described. The results appear to differ from patient to patient as far as the relative proportion in the number and length of pauses before correct words and mistakes is concerned. Generalization of the conclusion beyond single cases may not therefore be legitimate.

ERP indexes of functional differences in brain activation during proper and common names retrieval.

Functional neuroimaging and neuropsychological findings suggest that memory retrieval of common and proper names is subserved by different neuro-functional systems but little is known about the topographic localization of neural generators. In the present study brain electrical activity was recorded with a high density electrode montage in healthy young volunteers during lexical retrieval upon written definition. ERPs spatio-temporal mapping showed on one side a strong activation of left anterior temporal and left central-frontal areas for proper names, and on the other side a greater involvement of occipital areas for common names retrieval. The specific pattern of bio-electrical activity recorded during proper names retrieval might index the activation of neural circuits for recalling names of high contextual complexity, poor of sensory-motor associations and dependent on precise spatio-temporal coordinates.