Using the Chinese Smell Identification Test to explore olfactory function in Parkinson's disease

Smell loss is associated with cognitive impairment in amyotrophic lateral sclerosis patients

BACKGROUND

Smell loss significantly impacts the quality of life in patients. However, there is limited research on smell loss in individuals with amyotrophic lateral sclerosis (ALS), and the correlation between smell loss and cognitive impairment is unclear. This study aimed to investigate the correlation between smell loss and cognition impairment in ALS patients.

METHODS

The study included 216 ALS patients. The Edinburgh Cognitive and Behavioural ALS Screen (ECAS) and smell identification test specifically for the Chinese population (CSIT) were administered to evaluate participants' cognitive and olfactory function, respectively.

RESULTS

After covarying for age, sex, BMI, education level, degree of hunger, dietary bias, eagerness for food, stress, smoking status, alcohol consumption, and upper respiratory tract infection (URTI) or rhinitis, CSIT scores were significantly correlated with ECAS scores (r = 0.162, p = 0.028), especially the ALS-specific scores (r = 0.158, p = 0.031). Even after excluding patients with URTI or rhinitis, the results were similar. CSIT scores were significantly correlated with ECAS scores (r = 0.224, p = 0.011), especially the ALS-specific scores (r = 0.205, p = 0.019).

CONCLUSION

In patients with ALS, smell loss is significantly correlated with cognitive impairment, particularly frontotemporal dysfunction. Cognitive dysfunction may lead to worse olfactory performance in ALS patients.

China's Modified Version of Sniffin' Sticks 12-Identification Test Used in Chinese Parkinson's Disease and Multiple System Patients: Comparison of Three Olfactory Testing Methods

Objectives

The aim of this study was to compare the Sniffin' Sticks 12-identification test (SIT-12), China-modified version of the SIT-12 test (Ch-SIT-12) and brief smell identification test for Chinese (B-SITC) in Chinese population of Parkinson's disease (PD) and multiple system atrophy (MSA).

Methods

36 patients with PD and 7 patients with MSA were enrolled in this study. Three olfactory testing methods (SIT-12, Ch-SIT-12, and B-SITC) were used to test the olfactory function in all participants. Furthermore, demographic and clinical data were collected.

Results

There was no significant difference between three olfactory tests in patients with PD (B-SITC vs. SIT-12: P=0.508; Ch-SIT-12 vs. B-SITC: P=0.146; and SIT-12 vs. Ch-SIT-12: P=0.375). Tremor-dominant (TD) subtypes have better olfactory function than akinetic-rigid dominant (ARD) subtypes when using Ch-SIT-12 (77.8% vs. 29.6%, P=0.019) or B-SITC (55.6% vs. 14.8%, P=0.026). There was a statistical difference between the PD and MSA using Ch-SIT-12 to test the olfactory function (P=0.046).

Conclusions

Our results indicated that SIT-12, Ch-SIT-12 and B-SITC can be used for the detection of olfactory dysfunction in Chinese population of PD. TD subtypes may have better olfactory function than ARD subtypes. In addition, Ch-SIT-12 may be used to differentiate PD from MSA, but that should be confirmed in a larger population.

Mixed hypogonadism: a neglected combined form of hypogonadism

PURPOSE

Kallmann syndrome is a rare disease characterized by delayed puberty, infertility and anosmia. We report the clinical and genetic characteristics of three patients with Kallmann syndrome who presented with Klinefelter syndrome and defined this neglected combined form of hypogonadism as mixed hypogonadism.

METHODS

Clinical data and examinations were obtained, including laboratory examination and magnetic resonance imagination (MRI) of the olfactory structures. Congenital hypogonadotropic hypogonadism (CHH) related genes were screened by next generation sequencing (NGS).

RESULTS

Three patients with Kallmann syndrome were included. They had co-existence with Klinefelter syndrome and showed hypogonadotropic hypogonadism. Patient 1 was complicated with germinoma.

CONCLUSION

Mixed hypogonadism was defined as hypogonadotropic hypogonadism in Klinefelter syndrome or primary testicular disease. Clinicians should be alert to mixed hypogonadism when spermatogenesis induction failed in patients with CHH or gonadotropin levels decrease in patients with Klinefelter syndrome.

Olfactory function changes and the predictive performance of the Chinese Smell Identification Test in patients with mild cognitive impairment and Alzheimer's disease

Objectives

Olfactory disorder is one of the sensory features that reflects a decline in cognitive function. However, olfactory changes and the discernibility of smell testing in the aging population have yet to be fully elucidated. Therefore, this study aimed to examine the effectiveness of the Chinese Smell Identification Test (CSIT) in distinguishing individuals with cognitive decline from those with normal aging and to determine whether the patients with MCI and AD show changes in their olfactory identification abilities.

Methods

This cross-sectional study included eligible participants aged over 50 years between October 2019 and December 2021. The participants were divided into three groups: individuals with mild cognitive impairment (MCI), individuals with Alzheimer's disease (AD), and cognitively normal controls (NCs). All participants were assessed using neuropsychiatric scales, the Activity of Daily Living scale, and the 16-odor cognitive state test (CSIT) test. The test scores and the severity of olfactory impairment were also recorded for each participant.

Results

In total, 366 eligible participants were recruited, including 188 participants with MCI, 42 patients with AD, and 136 NCs. Patients with MCI achieved a mean CSIT score of 13.06 ± 2.05, while patients with AD achieved a mean score of 11.38 ± 3.25. These scores were significantly lower than those of the NC group (14.6 ± 1.57; P < 0.001). An analysis showed that 19.9% of NCs exhibited mild olfactory impairment, while 52.7% of patients with MCI and 69% of patients with AD exhibited mild to severe olfactory impairment. The CSIT score was positively correlated with the MoCA and MMSE scores. The CIST score and the severity of olfactory impairment were identified as robust indicators for MCI and AD, even after adjusting for age, gender, and level of education. Age and educational level were identified as two important confounding factors that influence cognitive function. However, no significant interactive effects were observed between these confounders and CIST scores in determining the risk of MCI. The area under the ROC curve (AUC) generated from the ROC analysis was 0.738 and 0.813 in distinguishing patients with MCI and patients with AD from NCs based on the CIST scores, respectively. The optimal cutoff for distinguishing MCI from NCs was 13, and for distinguishing AD from NCs was 11. The AUC for distinguishing AD from MCI was 0.62.

Conclusions

The olfactory identification function is frequently affected in patients with MCI and patients with AD. CSIT is a beneficial tool for the early screening of cognitive impairment among elderly patients with cognitive or memory issues.

The diagnostic value of the olfactory evaluation for congenital hypogonadotropic hypogonadism

OBJECTIVE

The aim of this study was to evaluate the diagnostic accuracy of different olfactory evaluation tools in congenital hypogonadotropic hypogonadism (CHH) patients.

METHODS

Seventy-one CHH patients were prospectively recruited at Peking Union Medical College Hospital between November 2020 and July 2021. The Chinese Olfactory Function Test (COFT) and Self-reported Olfactory Scale (SROS) were adapted as the subjective tools for the evaluation of olfactory function, and magnetic resonance imaging of olfactory apparatus (MRI-OA) was the objective tool. The olfactory bulb volume (OBV) and the olfactory sulcus depth (OSD) were quantified.

RESULTS

Based on the COFT, 36 patients were categorized as having normosmic CHH (nCHH), and the other 35 patients were categorized as having Kallmann syndrome (KS). Among nCHH patients, 35 patients were classified as having normal olfaction and 1 patient had abnormal olfaction by SROS. For KS patients, there were 30 patients grouped into abnormal olfaction, while 5 patients had normal olfaction by SROS. For MRI-OA, 67% (18/27) of nCHH patients showed normal olfactory apparatus, and 33% (9/27) showed bilateral or unilateral olfactory bulb aplasia or hypoplasia. Among KS patients, 96% (27/28) of patients showed bilateral olfactory bulb hypoplasia or aplasia, and 4% (1/28) of patients showed normal olfactory apparatus. All six patients with unilateral olfactory bulb aplasia and three patients with bilateral olfactory bulb aplasia showed normal olfactory function. The accuracy of the SROS in the diagnosis of nCHH and KS was 91.5%, with a sensitivity of 0.857 and a specificity of 0.972, while the accuracy of MRI-OA is 92.7%, with a sensitivity of 0.964 and a specificity of 0.889.

CONCLUSION

SROS and MRI-OA both showed high accuracy to distinguish between KS and nCHH. The abnormal structure of the olfactory apparatus was relatively common in nCHH patients. CHH patients with unilateral olfactory bulb aplasia dysplasia usually had normal olfaction. Normal olfaction without apparent olfactory bulbs is rare but occurred in male CHH patients.