Social Cognition and Cognitive Decline in Patients with Parkinson's Disease.

Social cognition (SC) comprises an array of cognitive and affective abilities such as social perception, theory of mind, empathy, and social behavior. Previous studies have suggested the existence of deficits in several SC abilities in Parkinson disease (PD), although not unanimously. OBJECTIVE: The aim of this study is to assess the SC construct and to explore its relationship with cognitive state in PD patients. METHOD: We compare 19 PD patients with cognitive decline, 27 cognitively preserved PD patients, and 29 healthy control (HC) individuals in social perception (static and dynamic emotional facial recognition), theory of mind, empathy, and social behavior tasks. We also assess processing speed, executive functions, memory, language, and visuospatial ability. RESULTS: PD patients with cognitive decline perform worse than the other groups in both facial expression recognition tasks and theory of mind. Cognitively preserved PD patients only score worse than HCs in the static facial expression recognition task. We find several significant correlations between each of the SC deficits and diverse cognitive processes. CONCLUSIONS: The results indicate that some components of SC are impaired in PD patients. These problems seem to be related to a global cognitive decline rather than to specific deficits. Considering the importance of these abilities for social interaction, we suggest that SC be included in the assessment protocols in PD.

Pattern of neurocognitive function in patients receiving boosted protease inhibitor monotherapy: a detailed neuropsychological study.

It is unknown if, compared to a triple drug antiretroviral therapy, boosted protease inhibitor monotherapy leads to worse results in specific neuropsychological processes. In our study, we included patients virologically suppressed (≥1 year), on antiretroviral therapy, without concomitant major neurocognitive confounders, receiving boosted lopinavir or darunavir as monotherapy (n = 96) or as triple therapy with two nucleoside reverse transcriptase inhibitors (n = 95). All patients underwent a comprehensive neuropsychological test battery (14 neuropsychological measures, covering seven domains). Both groups were compared in average score distributions and rates of neuropsychological deficits. Similar comparisons were conducted only for patients with neurocognitive impairment. In the adjusted analysis, we found only small differences between groups in the entire sample: better verbal learning (p = 0.02; d = 0.28) and verbal recall scores (p < 0.01; d = 0.25) in patients on boosted protease inhibitor monotherapy and slightly better motor skills with dominant hand (p = 0.02; d = 0.23) scores in patients on triple therapy. No greater proportion of deficits in the protease inhibitor monotherapy group was found in any neuropsychological measure. In neurocognitively impaired patients, we found similar outcomes in verbal learning, verbal recall, and motor skills with dominant hand but with larger effect sizes. Close similarities in the neurocognitive pattern between groups question the clinical relevance of the number of neuroactive drugs included in the regimen. These results also suggest that peripheral viral load control may be a good indicator of brain protection.

Is a neutral expression also a neutral stimulus? A study with functional magnetic resonance.

Although neutral faces do not initially convey an explicit emotional message, it has been found that individuals tend to assign them an affective content. Moreover, previous research has shown that affective judgments are mediated by the task they have to perform. Using functional magnetic resonance imaging in 21 healthy participants, we focus this study on the cerebral activity patterns triggered by neutral and emotional faces in two different tasks (social or gender judgments). Results obtained, using conjunction analyses, indicated that viewing both emotional and neutral faces evokes activity in several similar brain areas indicating a common neural substrate. Moreover, neutral faces specifically elicit activation of cerebellum, frontal and temporal areas, while emotional faces involve the cuneus, anterior cingulated gyrus, medial orbitofrontal cortex, posterior superior temporal gyrus, precentral/postcentral gyrus and insula. The task selected was also found to influence brain activity, in that the social task recruited frontal areas while the gender task involved the posterior cingulated, inferior parietal lobule and middle temporal gyrus to a greater extent. Specifically, in the social task viewing neutral faces was associated with longer reaction times and increased activity of left dorsolateral frontal cortex compared with viewing facial expressions of emotions. In contrast, in the same task emotional expressions distinctively activated the left amygdale. The results are discussed taking into consideration the fact that, like other facial expressions, neutral expressions are usually assigned some emotional significance. However, neutral faces evoke a greater activation of circuits probably involved in more elaborate cognitive processing.

Does the Montreal Cognitive Assessment (MoCA) identify cognitive impairment profiles in Parkinson's disease? An exploratory study.

An important proportion of patients with Parkinson's Disease (PD) present signs of cognitive impairment, although this is heterogeneous. In an attempt to classify this, the dual syndrome hypothesis distinguishes between two profiles: one defined by attentional and executive problems with damage in anterior cerebral regions, and another with mnesic and visuospatial alterations, with damage in posterior cerebral regions. The Montreal Cognitive Assessment (MoCA) is one of the recommended screening tools, and one of the most used, to assess cognitive impairment in PD. However, its ability to specifically identify these two profiles of cognitive impairment has not been studied. The aim of this study was, therefore, to analyze the capacity of the MoCA to detect cognitive impairment, and also to identify anterior and posterior profiles defined by the dual syndrome hypothesis. For this purpose, 59 patients with idiopathic PD were studied with the MoCA and a neuropsychological battery of tests covering all cognitive domains. Results of logistic regression analysis with ROC (Receiver Operating Characteristic) curves showed that MoCA detected cognitive impairment and identified patients with a profile of anterior/attentional and executive deficit, with acceptable sensibility and specificity. However, it did not identify patients with a posterior/mnesic-visuospatial impairment. We discuss the reasons for the lack of sensitivity of MoCA in this profile, and other possible implications of these results with regards the usefulness of this tool to assess cognitive impairment in PD.

Emotional Processing in Healthy Ageing, Mild Cognitive Impairment, and Alzheimer's Disease.

Emotional processing, particularly facial expression recognition, is essential for social cognition, and dysfunction may be associated with poor cognitive health. In pathological ageing conditions, such as mild cognitive impairment (MCI) and Alzheimer's disease (AD), in which cognitive impairments are present, disturbed emotional processing and difficulty with social interactions have been documented. However, it is unclear how pathological ageing affects emotional processing and human social behaviour. The aim of this study is to provide insight into how emotional processing is affected in MCI and AD and whether this capacity can constitute a differentiating factor allowing the preclinical diagnosis of both diseases. For this purpose, an ecological emotional battery adapted from five subsets of the Florida Affect Battery was used. Given that emotion may not be separated from cognition, the affect battery was divided into subtests according to cognitive demand, resulting in three blocks. Our results showed that individuals with MCI or AD had poorer performance on the emotional processing tasks, although with different patterns, than that of controls. Cognitive demand may be responsible for the execution patterns of different emotional processing tests. Tasks with moderate cognitive demand are the most sensitive for discriminating between two cognitive impairment entities. In summary, emotional processing tasks may aid in characterising the neurocognitive deficits in MCI or AD. Additionally, identifying these deficits may be useful for developing interventions that specifically target these emotional processing problems.

Neuropsychological profile of adults with Down syndrome and moderate intellectual disability.

BACKGROUND: The neuropsychological profile of individuals with Down syndrome (DS) has been described as being characterized by dissociations between verbal and visual abilities, as well as between verbal comprehension and production abilities (higher visual than verbal abilities and higher verbal comprehension than verbal production abilities). However, the studies that reached these conclusions based these conclusions mainly on inter-group differences in children but not on intra-group differences. AIMS: The study explores dissociations in adults with DS, taking inter-group and intra-group differences into account. METHOD AND PROCEDURES: The sample was composed of 40 adults with DS and 38 adults with moderate intellectual disability (ID) but without DS, matched for chronological age, sex, and intellectual level. OUTCOMES AND RESULTS: The participants with DS, unlike the other group, exhibited similar performance in their verbal and visual abilities, as well as in their verbal comprehension and production abilities (intra-group differences). In addition, they showed worse performance in verbal general measures and verbal comprehension abilities but similar performance in visual general measures and verbal production abilities (inter-group differences) compared with those without DS with similar intellectual levels on standardized measures. CONCLUSIONS AND IMPLICATIONS: The observed intra-group differences highlight that a lack of dissociation between verbal and visual abilities, as well as between verbal comprehension and production abilities, seems to be a specific feature of adults with DS.

Verbal emotional memory laterality effect on amygdalohippocampectomy for refractory epilepsy.

OBJECTIVES: To study the brain lateralization of the verbal emotional memory and the influence of the emotional valence, we investigated a sample composed of patients with medial temporal lobe refractory epilepsy (MTLE) treated with unilateral amygdalohippocampectomy compared to a control group. MATERIALS & METHODS: A new task (Verbal Association) was designed and implemented to assess emotional memory performance. It was applied to 62 patients with MTLE of whom 31 have been subjected to right amygdalohippocampectomy and 31 to left amygdalohippocampectomy. These patients were compared with 31 participants with no cerebral pathology, as a control group. RESULTS: (a) The control group obtained a higher number of recalled words than the rest of the groups, while the MTLE-right group obtained better results than the MTLE-left group. (b) In the case of positive emotional valence words, the MTLE-left group performed significantly worse than the rest of the groups; whereas for negative emotional words, the MTLE-left group presented the lowest average performance and the control group obtained a higher number of recalled words compared to MTLE-right group. In the case of neutral emotional words, no significant differences were found among the groups. (c) The MTLE-left group showed poorer performance on positive and negative words than neutral; the control group demonstrated lower average performance on positive and neutral words compared to negative; the MTLE-right group did not show any significant differences on the recall of different emotional valences. CONCLUSIONS: Patients with MTLE show a deficit in the verbal recall which is exacerbated for information with an affective component. This deficit is more prominent in the case of patients with left unilateral resection (MTLE-left group) since they lose the benefits of the emotional information for the recall.

Perception and recall of faces and facial expressions following temporal lobectomy.

The perception of and memory for faces, with or without emotional content, were studied in 43 patients with temporal lobe epilepsy who had undergone unilateral resection of the hippocampus and the amygdala and in 43 healthy participants for comparison. Each participant performed four tasks from the Florida Affect Battery (Facial Discrimination, Affect Discrimination, Affect Naming, Affect Selection) and two memory tasks (in one case of a face and in the other of a facial expression). Findings indicated that, although patients with unilateral temporal lobectomy (right or left) showed no difficulty in discriminating faces, they were not as good at remembering faces. Also, patients who had had a left temporal lobectomy showed impairment in discriminating facial expressions, in the memory of a facial expression and/or in naming facial expressions.

Impact of Surgical Site Infections on Elective Incisional Hernia Surgery: A Prospective Study.

BACKGROUND: Although incisional hernia repair is classified as a clean surgery, it still has a high incidence of surgical site infection (SSI) (0.7%-26.6%). The presence of an SSI could increase early recurrence rates after incisional hernia repair. PATIENTS AND METHODS: Patients undergoing elective incisional hernia repair with no bowel contamination between January and December 2015 were assessed prospectively. Demographic and surgical data, local post-operative complications, and one-year recurrence rates in patients with and without SSI were compared. The management of SSI was determined. RESULTS: Patients with SSI (16/101) showed more prolonged surgical procedures (91 ± 39 vs. 63 ± 30 min, p = 0.012), more post-operative sero-hematomas (38% vs. 8%, p = 0.001), and a higher one-year recurrence rate (19% vs. 4%, p = 0.047). Multivariable analysis revealed the only identified risk factor for SSI to be post-operative sero-hematomas (p = 0.042; odds ratio [OR] = 4.17 [1.05-16.54]). Patients who developed an SSI required antibiotic agents and daily treatment from one to five months. One of these required the removal of the mesh. CONCLUSIONS: Surgical site infection rates are high for incisional hernia surgery (16%), and associated with local complications. Surgical site infection requires long-term treatments and leads to a higher one-year recurrence rate.

The role of the amygdala in facial emotional expression during a discrimination task.

A total of 50 patients with temporal lobe epilepsy with unilateral resection of the hippocampus and the amygdala were studied: --27 with left lobectomy (LTL group) and 23 with right lobectomy (RTL group)--; and 28 healthy control participants (HC group). The task consisted of identifying the dissimilar photograph from a group of photographs of the same face. The difference could correspond to the identity of the model or the facial expression (happiness, anger, sadness and fear). The results showed that when the difference in the photograph resided in the identity of the model, the RTL group made more mistakes than the HC group. When the facial expression was the distinguishing feature, mean response latency was longer in the LTL group than in the HC group. Comparison of the emotions revealed that the greatest differences were obtained with the fear expression, in all three participant groups. The dissociation of neural circuits responsible for processing facial expressions is discussed and, especially, the role of the left amygdala to discriminate between facial expressions.

Single-incision laparoscopy versus standard laparoscopy for colorectal surgery: A systematic review and meta-analysis.

The aim of this meta-analysis was to evaluate if the advantages of single-incision laparoscopic surgery (SILS) to perform a colorectal resection justify a broad application of this approach. A total of 32 studies including 3863 patients, comparing colorectal procedures performed with SILS or multi-port laparoscopy (LCS) were analyzed after a systematic review. Colorectal SILS had comparable outcomes to multi-port LCS in terms of operating time (P = 0.44), conversion rate (2.0% vs 3.0%; P = 0.52), reoperations (1.1% vs 1.7%; P = 0.26), postoperative complications (14.4% vs 13.6%; P = 0.10) and mortality (0.24% vs 0.68%; P = 0.46). Mean hospital stay was significantly shorter in CSILS group, (MD = -0.88 [-1.33, -0,42], 95% CI, P = 0.0001), but heterogeneity was found (I2 = 65%; P < 0.0001). The oncological results of SILS for colorectal cancer were satisfactory, as demonstrated by similar average lymph node retrieval (P = 0.72) and adequate resection margins (negative in all cases) compared to those obtained with LCS. Nevertheless, there are currently no available long-term follow-up data comparing the survival rates and local recurrence between both approaches. Insufficient data were available for evaluating long-term incisional hernia rates, and other potential benefits associated with colorectal SILS (cosmesis, postoperative pain) remain to be objectively proved. To date there is insufficient evidence to recommend widespread use of SILS instead of LCS for colorectal surgery.

Categorización y revisión de reevaluaciones en tomografía computada en una unidad de telerradiología de urgencia / Categorization and review of reevaluations in computed tomography in an emergency teleradiology unit

INTRODUCCIÓN La telerradiología se basa en el despliegue de radiólogos a distancia para evaluar estudios de dicha especialidad. Actualmente hay evidencia limitada sobre las tasas de error de evaluaciones en telerradiología. Este estudio corresponde a una revisión de las discrepancias entre los informes preliminares y finales de tomografía computada (TC) de una unidad de urgencia telerradiológica. OBJETIVO Determinar las discrepancias de las reevaluaciones (addendum) en los informes radiológicos de TC en una unidad de telerradiología de urgencia. MATERIALES Y MÉTODOS La recolección de datos se planificó a modo de tabla de cotejo, en la cual se tabularon casos de reevaluaciones de urgencia desde el mes de enero hasta mayo del año 2021, en base a la categorización Agrawal. RESULTADOS De una total de 111.599, 836 informes presentaron addendum, que corresponden al 0,74% del total informado, La categoría Agrawal 0 agrupó la mayor cantidad de casos y los exámenes de TC especialidad de cuerpo se encuentran los segmentos con mayores requerimientos de reevaluación. Discusión: Los valores obtenidos permiten establecer una baja incidencia de reevaluaciones y de la gravedad de estas, apuntando a errores asociados a canales de comunicación, redacción y elaboración de informes con especial énfasis en estudios TC Tórax y Abdomen/Pelvis. CONCLUSIÓN El porcentaje de cumplimiento de un 99,26% de exactitud en los informes permite concluir la alta confiabilidad y la calidad del servicio de telerradiología de la empresa en cuestión durante el periodo evaluado y el empleo de medidas correctivas basadas en organización, gestión e instrumentalización tecnológica

HAL-RAR (Doppler guided haemorrhoid artery ligation with recto-anal repair) is a safe and effective procedure for haemorrhoids. Results of a prospective study after two-years follow-up.

PURPOSE: To analyse prospectively results of HAL-RAR technique by evaluating pain, perioperative complications and clinical outcome after two years followup. METHODS: A prospective study design including 30 consecutive patients with haemorrhoids grade III-IV treated from June 2012. After discharge, patients received a specific questionnaire to record postoperative pain, delayed complications, evolution/disappearance of the symptoms that led to the surgical intervention (bleeding, prolapse, itching, pain and soiling). A visual analog scale (VAS) was used to measure pain. Outpatient follow-up was carried out at 7 days, and 1, 6 and 12 months and annually thereafter. Pre, intra and postoperative data (including physical examination) had been recorded prospectively. RESULTS: The median operating time (range) was 40 (26-60) minutes. Average hospital stay (range) was 11 (3-25) hours. No postoperative complications were observed in 29 cases (96.6%). Median follow-up was 26 (12-36) months. All the patients attended the follow-up. Mean postoperative pain was VAS = 1.7 on the seventh day and it was practically non-existent (VAS = 0.7) 1 month after the procedure. 87.5% of patients confirmed complete relief of symptoms after 30 days and 93% of patients feel free of symptoms 6 months after the procedure. No patient has experienced late complications as dyschezia, urgency, soiling or faecal incontinence. After 24 months follow-up, recurrence of bleeding and prolapse was observed in only 1 patient; 93% of patients have considered results of HAL-RAR as very good or excellent. CONCLUSION: HAL-RAR is safe and almost painless technique and it has very good results in the control of haemorrhoidal symptoms. This procedure should be considered as an effective first treatment option for haemorrhoids.

Resolución quirúrgica de escoliosis congénita: reporte de caso / Surgical resolution of congenital scoliosis: case report

Las deformidades congénitas de la columna vertebral, constituyen uno de los trastornos musculoesqueléticos no traumáticos de difícil manejo clínico quirúrgico, por el alto grado de deformidad que producen y porque su incidencia es menor que las idiopáticas. Se presenta el caso de una paciente de 14 años de edad, quien fue valorada en una consulta externa del Hospital Carlos Andrade Marín de la ciudad de Quito, Ecuador, con una deformidad severa toracolumbar, presente desde el nacimiento, que ha ido progresando hasta causar dolor a la movilidad y limitando sus actividades diarias, impidiendo un desarrollo social adecuado, por lo que, se decide su resolución quirúrgica mediante artrodesis posterior instrumentada, osteotomías correctivas y resección de hemivértebra y barra espinal, posterior a lo cual se realizó fisioterapia y un seguimiento por consulta externa de un año. Su evolución fue favorable, mejorando su sintomatología y movilidad.

Congenital deformities of the spine constitute one of the non-traumatic musculoskeletal disorders of difficult clinical surgical management, due to the high degree of deformity they produce and their incidence is lower than idiopathic ones. We present the case of a 14-year-old patient who was evaluated in the outpatient clinic of the Carlos Andrade Marín Hospital in the city of Quito, Ecuador, with a severe thoracolumbar deformity, present from birth, which has progressed to cause pain to mobility, limiting daily activities, preventing an adequate social development, for which, surgical resolution was decided through instrumented posterior arthrodesis, corrective osteotomies, and resection of hemivertebra and spinal rod, after which physiotherapy was performed and follow-up by external consultation for 1 year. Its evolution was favorable, improving its symptomatology and mobility.

A holistic analysis of relationships between executive function and memory in Parkinson's disease.

Apart from motor symptoms, Parkinson's disease is characterized by executive and memory problems that have been observed from early stages of the disease. This study explores the possible relationships between these cognitive impairments in a group of 23 individuals with Parkinson's disease (PD) in comparison to a group of 18 healthy individuals. Compared with young individuals, normal aging is characterized by an increased association between executive function and episodic memory, especially with verbal material. We hypothesize that this association between verbal episodic memory and executive function may be weaker in PD as a consequence of the decline in these two cognitive abilities. To test this hypothesis, three categories of standardized tests were administered to both groups: (a) tests for executive function, (b) tests for visuospatial episodic memory, and (c) tests for verbal episodic memory. Performance outputs were analyzed using factor analysis, canonical regression, and structural equation modeling to obtain a holistic perspective of the linkage of these processes and to compare the differences between groups. In general, PD patients performed worse than controls in both executive function and episodic memory (with verbal and visuospatial material). Moreover, we found that relationships between executive function and visuospatial memory scores were high and quite similar in both groups. However, the relationship between verbal episodic memory and executive function was weaker in PD than in healthy individuals. These results suggest that a different brain mechanism could explain executive and verbal memory impairments in PD.

Efecto del extracto de alcaloides de Berberis darwinii Hook sobre respuestas celulares innatas en fagocitos murinos / Effect of the extract of Berberis darwinii Hook alkaloids on innate cellular responses in murine phagocytes

Berberis darwinii Hook es una especie que habita el sur de Chile y la Patagonia. Siendo utilizada por la etnia mapuche para el tratamiento de procesos inflamatorios, estados febriles, y dolor estomacal. El propósito del siguiente estudio fue evaluar in vitro las propiedades del extracto de alcaloides de raíz de B. darwinii sobre respuestas celulares en monocitos desde sangre periférica de rata. Los resultados de la cuantificación del extracto muestran una concentración de alcaloides totales de 1,67 mg/g y la caracterización por HPLC- MS determinó la presencia de berberina y palmatina. In vitro se observó que los extractos disminuyeron la capacidad de adhesión y la actividad fagocítica de los monocitos e inhibieron la translocación del factor nuclear NF-κB asociado a la modulación de la inflamación, pero no así la producción de anión superóxido. Estos resultados indicarían que los alcaloides totales de B. darwinii inhiben algunos mecanismos específicos de defensa celular.

Berberis darwinii Hook is a species that inhabits southern Chile and Patagonia. This is being used by the Mapuche ethnic group for the treatment of inflammatory processes, febrile states, and stomach pain. The purpose of the following study was to evaluate in vitro the properties of an alkaloid extract of B. darwinii root on cellular responses in monocytes from the rat peripheral blood. The results of the quantification of the extract showed a total alkaloid concentration of 1.67 mg/g and the characterization by HPLC-MS determined the presence of berberine and palmatine. In vitro, it was observed that the extracts decreased the adhesion capacity and phagocytic activity of the monocytes and inhibited the translocation of the nuclear factor NF-κB associated with the modulation of inflammation, but not the production of superoxide anion. These results indicate that the total alkaloids of B. darwinii inhibit some specific mechanisms of cellular defense.

Processing of facial expressions of emotions by adults with Down syndrome and moderate intellectual disability.

The processing of facial expressions of emotions by 23 adults with Down syndrome and moderate intellectual disability was compared with that of adults with intellectual disability of other etiologies (24 matched in cognitive level and 26 with mild intellectual disability). Each participant performed 4 tasks of the Florida Affect Battery and an original task in which they had to match facial expressions after observing the complete face or one of its halves. Adults with Down syndrome did not show any specific difficulties in recognizing facial expressions in spite of showing a poorer discrimination between facial expressions and tended to take more notice of the lower half of the face.

Field evaluation of a self-propelled sprayer and effects of the application rate on spray deposition and losses to the ground in greenhouse tomato crops.

BACKGROUND: In the greenhouses of south-eastern Spain, plant protection products are applied using mainly sprayers at high pressures and high volumes. This results in major losses on the ground and less than uniform spray deposition on the canopy. Recently, self-propelled vehicles equipped with vertical spray booms have appeared on the market. In this study, deposition on the canopy and the losses to the ground at different spray volumes have been compared, using a self-propelled vehicle with vertical spray booms versus a gun sprayer. Three different spray volumes have been tested with a boom sprayer, and two with a spray gun. RESULTS: The vehicle with the vertical spray boom gave similar depositions to those made with the gun, but at lower application volumes. Also, the distribution of the vertical spray boom was more uniform, with lower losses to the ground. CONCLUSIONS: The vertical spray booms used in tomato crops improve the application of plant protection products with respect to the spray gun, reducing the application volumes and the environmental risks of soil pollution.

Judgements of facial and vocal signs of emotion in infants with Down syndrome.

We address how adults perceive facial and vocal signs of emotions in infants with and without Down syndrome. A set of naturalistic data from infants with trisomy 21 and typically developing infants (joy expression of young infants, 3.8-4.4 months, and anger and neutral expressions of older infants, 6.8-12.8 months) was rated by adult judges categorically or dimensionally. Facial signs alone, vocal signs alone, and both facial and vocal signs were presented for each expression. Raters were university students who did not have regular contact with infants, nor with people with mental retardation. Young infants' joy expressions were correctly recognized more frequently for typically developing infants than for infants with Down syndrome and, specifically, joy vocalizations in infants with Down syndrome were not identified. Facial signs were also more communicative than vocal signs in the case of older infants' anger and neutral expressions. These results are relevant to the way infant emotion is perceived by others, and may be particularly useful in facilitating interaction between adults and infants with Down syndrome.

Knodus shinahota (Characiformes: Characidae) a new species from the río Shinahota, río Chapare basin (Mamoré system), Bolivia

Knodus shinahota, new species, is described from río Shinahota, a tributary of the upper rio Mamoré basin, Província de Tiraque, Cochabamba State, Bolivia. The new species can be distinguished from all congeners except K. chapadae and K. geryi by having six rows of scales between the lateral line and the dorsal-fin origin (vs 4 or 5 rows of scales in the other species). Knodus shinahota differs from K. chapadae by possessing more rows of scales between the lateral line and the pelvic-fin origin (5 vs 3® or 4, respectively) and more lateral line scales (38-41 vs 36-38, respectively). It differs from K. geryi by possessing more rows of scales between the lateral-line and the pelvic-fin origin (5 vs 4, respectively); fewer branched anal-fin rays (17-20 vs 15-17, respectively), and by lacking the two symmetric, large, dark, blotches on the basal portions of the caudal-fin lobes that characterize K. geryi.

Knodus shinahota, espécie nova, é descrita do río Shinahota, um afluente do alto da bacia do rio Mamoré, Província de Tiraque, Estado de Cochabamba, Bolívia. A espécie nova pode ser distinguida de todas as suas congêneres exceto K. chapadae e K. geryi por ter seis fileiras de escamas entre a linha lateral e a origem da nadadeira dorsal (vs 4 ou 5 fileiras de escamas nas demais espécies). Knodus shinahota difere de K. chapadae por possuir mais fileiras de escamas entre a linha lateral e a origem da nadadeira pélvica (5 vs 3® ou 4, respectivamente) e mais escamas na linha lateral (38-41 vs 36-38, respectivamente). Difere de K. geryi por possuir mais fileiras de escamas entre a linha lateral e a origem da nadadeira pélvica (5 vs 4, respectivamente); menos raios ramificados na nadadeira anal (17-20 vs 15-17, respectivamente), e pela falta das duas grandes manchas escuras, simétricas, basalmente nos lobos da nadadeira caudal que caracteriza K. geryi.