You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Fasting for 24h improves nasal chemosensory performance and food palatability in a related manner
Abstract 1:
Changes in smell function can modify feeding behaviour but there is little evidence of how acute negative energy balance may impact olfaction and palatability . In a within-subjects repeated measures design , 15 subjects ( nine male ; six female ) aged 28.6±4.5 years with initial body weight ( BW ) 74.7±4.9 kg and body mass index ( BMI ) 25.3±1.4 kg/m(2 ) were r and omized  and tested at baseline ( FED ) and Post Deprivation ( FASTED ) for nasal chemosensory performance ( Sniffin ' Sticks ) and food palatability ( visual analogue scale ) . Significant main effects for time indicated improvements in the FASTED session for odor threshold , odor discrimination , and total odor scores ( TDI ) , and for increased palatability . There were significant positive correlations between initial BW and the change in odor threshold ( r=.52 ) and TDI scores ( r=.53 ) . Positive correlations were also noted between delta identification score and delta palatability ( r=.68 ) . When the sample was split by sex , only for females were there significant correlations between delta palatability and : delta BW ( r=.88 ) ; delta odor identification ( r=.94 ) ; and delta TDI score ( r=.85 ) . Fasting for 24h improved smell function and this was related to increased palatability ratings and initial BW . Further studies should confirm the role of BW and sex in the context of olfaction , energy deprivation and palatability


Title 2:
Test–Retest Reliability of Chemosensory Evoked Potentials
Abstract 2:
Summary This study investigated the test – retest reliability of chemosensory event-related potentials in humans .  Olfactory event-related potentials and chemosomatosensory event-related potentials were evaluated in 20 healthy , normosmic subjects .  Phenyl ethyl alcohol ( PEA , 40 % v/v ) and H2S ( 4 ppm ) served as olfactory stimuli whereas CO2 ( 60 % v/v ) was the chemosomatosensory stimulus . Fifteen stimuli of each compound were applied to each nostril . Identical stimulation sequences were used during three test sessions . Sessions 1 and 2 were separated by a mean of 6.8 days ; sessions 2 and 3 by 12.5 days .  Electroencephalographic recordings were made from Fz , Cz , Pz , C3 , and C4 . Amplitudes and latencies of P1 , N1 , P2 , N2 , and P3 were measured . Pearson ’s correlation coefficient was calculated to test the test – retest reliability , and the general linear model examined the differences . Most correlations ranged between 0.4 < r < 0.75 . Latencies correlated significantly better ( P = 0.008 ) between sessions than amplitudes , even though with CO2 stimulus amplitudes correlated significantly better than with PEA ( P = 0.006 ) or H2S ( P = 0.003 ) . No differences arose between measurements from different nostrils for any stimulus . Chemosensory event-related potentials show good test – retest reliability . Carbon dioxide amplitudes exhibit better signal-to-noise ratios than PEA or H2S amplitudes . Chemosensory event-related potentials are a clinical ly valuable objective and are reproducible


Title 3:
A study on the frequency of olfactory dysfunction.
Abstract 3:
OBJECTIVES /HYPOTHESIS Goals of the study were to evaluate the frequency of olfactory dysfunction in a large representative population without sinonasal complaints and to investigate the extent to which general pathological conditions , medications , and aging influence olfaction . STUDY DESIGN Prospect i ve . METHODS Results based on an odor identification test ( " Sniffin ' Sticks " ) were reported from 1240 subjects . The subjects presented themselves to an otorhinolaryngology outpatient clinic with relatively mild and transitory complaints unrelated to the upper airways . A detailed otorhinolaryngological examination in combination with a st and ardized interview further ascertained that these patients had no rhinological problems or symptoms relating to sinonasal disease . RESULTS Apart from the confirmation of the effects of age , gender , and certain otorhinolaryngological diseases on the sense of smell , the study results revealed that certain general diseases ( liver diseases , nonotolaryngological cancers ) appear to influence olfactory function , whereas other diseases or disorders have little or no impact on olfaction ( hypertension , cardiovascular problems ) . CONCLUSION The data in the study revealed that olfactory dysfunction among subjects under 65 years of age is more frequent than previously reported


Title 4:
Gustatory and olfactory sensitivity in patients with anorexia and bulimia in the course of treatment.
Abstract 4:
BACKGROUND The majority of studies on taste and smell in eating disorders have revealed several alterations of olfactory or gustatory functions . Aim of this prospect i ve study was to employ detailed olfactory and gustatory testing in female subjects of three homogenous groups - anorexia nervosa , bulimia nervosa and healthy controls - and to look at the effects of treatment on these measures . METHODS Sixteen hospitalized female patients with anorexia ( restricting type , mean age [M]=24.5 years ) , 24 female patients with bulimia ( purging type , M=24.3 years ) as well as 23 healthy controls ( M=24.5 years ) received  olfactory ( " Sniffin ' Sticks " ) and gustatory testing ( " Taste Strips " ) . Group differences in olfactory and gustatory sensitivity , body mass index ( BMI ) , the Beck depression inventory , the eating attitudes test ( EAT ) , and the influence of therapy on gustatory and olfactory function were investigated . RESULTS ( 1 ) Group differences were present for odor discrimination and overall olfactory function with anorexic patients having the lowest scores . ( 2 ) Regarding taste function , controls scored higher than patients with anorexia . ( 3 ) At admission small but significant correlations were found between overall olfactory function and body weight ( r(63)=0.35 ) , BMI ( r(63 ) = 0.37 ) , and EAT score ( r(63 ) = -0.27 ) . Similarly , ( 4 ) the taste test score correlated significantly with body weight ( r(63)= 0.48 ) , and BMI ( r(63 ) = 0.45 ) . Finally , ( 5 ) at discharge overall olfactory and gustatory function were significantly higher compared to admission in anorexic patients . CONCLUSIONS As compared to healthy controls and bulimic patients our results show lowered olfactory and gustatory sensitivities in anorexic patients that improved with increasing BMI and decreasing eating pathology in the course of treatment


Title 5:
Intact sensory function in anorexia nervosa.
Abstract 5:
BACKGROUND In anorexia nervosa ( AN ) , taste and smell are believed to be anhedonic , hunger and pain are muted , and body-image distortion obscures wasting , which together facilitate self-starvation . However , the emphasis on these deficits may be biased because other sensory systems have been sparsely investigated . OBJECTIVES Objectives of the study were to clarify whether these dysfunctions are specific or part of a pattern of sensory-perceptual deficits in AN patients and to test the gustatory senses dissociated from ingestion to clarify whether any deficit is sensory or affective . DESIGN In 15 adolescent , first-episode , hospitalized , restrictive AN patients and 15 matched healthy controls who responded to gustatory stimuli ( intensity and hedonics of 5 basic tastes and tastes and odors of foods and nonfoods ) , size estimation ( manual and oral judgment of size and shape , kinesthesia , and body size and esthetics ) , cold pain , and auditory and visual processing were compared . RESULTS AN patients did not differ on most tests , were better at odor recognition , were less successful in central auditory processing and oral assessment of size and shape , and may have been more sensitive to cold . Body-image dissatisfaction in AN patients was not related to dysfunctional size estimation . CONCLUSIONS There is no systematic sensory-perceptual deficit in AN patients , and specifically , not in gustatory function . The few differences shown might be due to fear of food-related stimuli or comorbidity
The general findings support that olfaction is altered in AN and in obesity and indicates toward there being little to no difference in olfactory capacity between BN patients and the general population .