Cerebral white matter lesions and regional blood flow are associated with reduced cognitive function in early-stage cognitive impairment

Background

Differences in the extent of cerebral white matter lesions (WML) and regional cerebral blood flow (rCBF) in early-stage cognitive impairment (ESCI) contribute to the prognosis of cognitive decline; however, it is unclear precisely how WML and rCBF affect cognitive decline in ESCI.

Objective

We examined the association between WML, rCBF, and cognitive impairment in the ESCI, using path analysis to clarify how these variables affect each other.

Methods

Eighty-three patients who consulted our memory clinic regarding memory loss were included in this study based on the Clinical Dementia Rating. Participants underwent the Mini-Mental State Examination (MMSE), brain magnetic resonance imaging (MRI) for voxel-based morphometry analysis, and brain perfusion single-photon emission computed tomography (SPECT) for rCBF evaluation in cortical regions, using 3D stereotactic surface projection (3D-SSP) analysis.

Results

Path analysis was performed on the MRI voxel-based morphometry and SPECT 3D-SSP data, showing a significant correlation between both and MMSE scores. In the most suitable model (GFI = 0.957), correlations were observed between lateral ventricular (LV-V) and periventricular WML (PvWML-V) volumes [standardized coefficient (SC) = 0.326, p = 0.005], LV-V and rCBF of the anterior cingulate gyrus (ACG-rCBF; SC = 0.395, p < 0.0001), and ACG-rCBF and PvWML-V (SC = 0.231, p = 0.041). Furthermore, a direct relationship between PvWML-V and MMSE scores was identified (SC = -0.238, p = 0.026).

Conclusion

Significant interrelationships were observed among the LV-V, PvWML-V, and ACG-rCBF that directly affected the MMSE score in the ESCI. The mechanisms behind these interactions and the impact of PvWML-V on cognitive function require further investigation.

White Matter Lesions May Aid in Differentiating Idiopathic Normal Pressure Hydrocephalus and Alzheimer's Disease

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is often misdiagnosed as Alzheimer's disease (AD) due to overlapping pathophysiology and similar imaging characteristics, including ventricular enlargement and increased white matter lesions (WMLs).

OBJECTIVE

To compare the extent and distribution of WMLs directly between iNPH and AD and examine the association with underlying pathophysiology.

METHODS

Twelve patients with iNPH (mean age: 78.08 years; 5 females), 20 with AD (mean age: 75.40 years; 13 females), and 10 normal cognition (NC) participants (mean age: 76.60 years; 7 females) were recruited. The extent and distribution of WMLs and the lateral ventricular volume (LV-V) were evaluated on MRI using voxel-based morphometry analysis. Concentrations of cerebrospinal fluid biomarkers, such as amyloid-β protein (Aβ)42, Aβ 40, Aβ 38, and tau species, were also measured. Risk factors for small vessel disease (SVD) were assessed by blood examination and medical records.

RESULTS

The periventricular WML volume (PWML-V) and deep WML volume (DWML-V) were significantly larger in iNPH than in AD and NC. The DWML-V was dominant in iNPH, while the PWML-V was dominant in AD and NC. GM-V was significantly smaller in AD than in iNPH and NC. The LV-V positively correlated with WML-V in all participants. There was a significant negative correlation between LV-V and Aβ 38 in iNPH. Furthermore, there was no significant difference in SVD risk factors between the groups.

CONCLUSION

The differences in the extent and distribution of WMLs between iNPH and AD, especially predominance of DWML-V over PWML-V in iNPH, may reflect decreased fluid and Aβ clearance.

[Marcel Proust: Birth of Neurology of Memory and Time in "In Search of Lost Time"]

Marcel Proust had interactions with a lot of neurologists through treatments of his asthma. His great work, "In Search of Lost Time", is one of the highest masterpieces in French literature, about which numerous reviews have been published from various angles as well as literature. This work is also important for neurology, as the origin of Proust's idea of creations is related to the neurology of memory and time. Especially, this article focuses on and discusses the Proust and the beginning of neurology of memory and time.

The Eyes Are More Eloquent Than Words: Anticipatory Looking as an Index of Event Memory in Alzheimer's Disease

Alzheimer's disease (AD) is a disorder in which individuals experience a difficulty in maintaining event memory for when, where, who, and what. However, verbal deficiency, one of the other symptoms of AD, may prevent a precise diagnosis of event memory because existing tests are based on verbal instructions by the tester and verbal response from patient. Therefore, non-verbal methods are essential to evaluate event memory in AD. The present study, using eye tracking, investigated whether AD patients deployed anticipatory looking to target acts related to future events based on previous experience when an identical video was presented to them twice. The results revealed the presence of anticipatory looking, although AD patients were unable to verbally report the content of the video. Our results illustrate that AD patients have a one-time event memory better than previously thought.

Serum BDNF as a Potential Biomarker of Alzheimer's Disease: Verification Through Assessment of Serum, Cerebrospinal Fluid, and Medial Temporal Lobe Atrophy

There is an urgent need to establish blood biomarkers for Alzheimer's disease (AD). Although it has been speculated that brain-derived neurotrophic factor (BDNF) is associated with AD, whether it can be used as a blood biomarker has yet to be determined. We used serum, cerebrospinal fluid (CSF), and medial temporal lobe atrophy from patients with AD to evaluate the association of BDNF with AD and assess its severity. For the blood analysis, 66 participants [21 normal controls (NCs) with normal cognitive function, 22 patients with mild cognitive impairment (MCI) due to AD, and 23 patients with AD] were included. For the CSF analysis, 30 participants were included. Magnetic resonance imaging, including a voxel-based specific regional analysis system for AD, and a Mini Mental State Examination were performed. Serum levels of BDNF and CSF levels of amyloid-β₄₂, total tau, and phosphorylated tau were measured using ELISA. Serum BDNF levels were significantly lower in the MCI due to AD group than in the NC group (p = 0.037). Although there was no significant difference in the AD group, there was a downward trend compared to the NC group. Serum BDNF levels were positively correlated with CSF Aβ₄₂ levels (r = 0.49, p = 0.005). There was a significant correlation between serum BDNF levels and medial temporal lobe atrophy. Decreased serum BDNF can potentially be used as a biomarker for early AD detection. Early detection of AD with a less invasive blood test is very beneficial, as it allows for intervention before dementia progresses.

Sex Differences in the Relationship of Serum Vitamin B1 and B12 to Dementia Among Memory Clinic Outpatients in Japan

Dementia and cognitive impairment are considered to be one of the biggest social and medical problems. While there is a definite relationship between vitamin B and cognitive decline, this has yet to be fully assessed with regard to sex differences. Thus, the present study investigated the relationship of vitamin B1 or vitamin B12 with dementia in accordance with the sex in 188 patients who visited the Memory Clinic at Showa University Hospital in Japan from March 2016 to March 2019. Cognitive function was tested by the Japanese version of the Mini-Mental State Examination (MMSE) and Hasegawa Dementia Scale-Revised (HDS-R). Blood tests were performed to measure the vitamin levels. Logistic regression analysis was used to calculate the odds ratio (OR) for dementia and the 95% confidence interval (CI). Compared to the highest vitamin group (third tertile), the lowest vitamin group (first tertile) exhibited a significantly increased OR for dementia defined by MMSE for vitamin B1 (OR:3.73, 95% CI:1.52–9.16) and vitamin B12 (2.97, 1.22–7.28) among women. In contrast, vitamin levels were not significantly associated with dementia determined by MMSE in men. These findings were similar even when dementia was defined by HDS-R. The present study suggests that vitamin B1 plays a role in preventing development of dementia in women. Future longitudinal studies will need to be undertaken in order to examine whether decreasing vitamin levels occur before or after cognitive impairment, and whether maintaining a higher vitamin level can prevent a worsening of cognitive function and the development of dementia.

Stopwatch training improves cognitive functions in patients with Parkinson's disease

Parkinson's disease (PD) impairs various cognitive functions, including time perception. Dysfunctional time perception in PD is poorly understood, and no study has investigated the rehabilitation of time perception in patients with PD. We aimed to induce the recovery of time perception in PD patients and investigated the potential relationship between recovery and cognitive functions/domains other than time perception. Sixty patients with PD (27 females) and 20 healthy controls (10 females) were recruited. The participants underwent a feedback training protocol for 4 weeks to improve the accuracy of subjective spatial distance or time duration using a ruler or stopwatch, respectively. They participated in three tests at weekly intervals, each comprising 10 types of cognitive tasks and assessments. After duration feedback training for 1 month, performance on the Go/No-go task, Stroop task, and impulsivity assessment improved in patients with PD, while no effect was observed after distance feedback training. Additionally, the effect of training on duration production correlated with extended reaction time and improved accuracy in the Go/No-go and Stroop tasks. These findings suggest that time perception is functionally linked to inhibitory systems. If the feedback training protocol can modulate and maintain time perception, it may improve various cognitive/psychiatric functions in patients with PD. It may also be useful in the treatment of diseases other than PD that cause dysfunctions in temporal processing.

Toxic Amyloid-β42 Conformer May Accelerate the Onset of Alzheimer's Disease in the Preclinical Stage

BACKGROUND

Toxic amyloid-β protein (Aβ) conformers play an important role in the progression of Alzheimer's disease (AD). The ratio of toxic conformer to total Aβ42 in cerebrospinal fluid (CSF) was significantly high in AD and mild cognitive impairment (MCI) due to AD using an enzyme-linked immunosorbent assay kit with a 24B3 antibody.

OBJECTIVE

We compared the toxic Aβ42, conformer at different stages of AD to identify its contribution to AD pathogenesis.

METHODS

We compared 5 patients with preclinical AD, 11 patients with MCI due to AD, 21 patients with AD, and 5 healthy controls to measure CSF levels of total Aβ42, total tau, tau phosphorylated at threonine 181 (p-tau), and toxic Aβ conformers. All were classified using the Clinical Dementia Rating. Cognitive function was assessed using the Japanese version of the Mini-Mental State Examination (MMSE-J).

RESULTS

Toxic Aβ conformer level was insignificant between groups, but its ratio to Aβ42 was significantly higher in AD than in preclinical AD (p < 0.05). Toxic Aβ42 conformer correlated positively with p-tau (r = 0.67, p < 0.01) and p-tau correlated negatively with MMSE-J (r = -0.38, p < 0.05).

CONCLUSION

Toxic Aβ conformer triggers tau accumulation leading to neuronal impairment in AD pathogenesis.

Cingulate Island Sign in Single Photon Emission Computed Tomography: Clinical Biomarker Correlations in Lewy Body Disease and Alzheimer's Disease

We compared 'CIScore' determined by quantitative single photon emission computed tomography studies of the cingulate island sign to cerebrospinal fluid (CSF) biomarkers in Lewy body disease (LBD) and Alzheimer's disease (AD) to assess its usefulness and pathological background. Among the 16 each age-matched LBD and AD patients, the CIScore differed significantly but was not correlated with CSF biomarkers. In LBD, hippocampal atrophy significantly correlated with Clinical Dementia Rating and CSF p-tau and t-tau levels. Our results showed CIS was not related to CSF biomarkers in LBD and high CSF tau levels were related to clinical disease severity and hippocampal atrophy.

Numbsense of shape, texture, and objects after left parietal infarction: A case report

Numbsense is a phenomenon, wherein patients can correctly respond to somatosensory stimuli at a higher rate than expected by chance, but cannot perceive the same stimuli consciously. Previously, numbsense has been reported in tactile localization of stimuli on the patient’s own body. Here, we describe a patient with numbsense that involved touched objects. The patient could not recognize the majority of somatosensory stimuli after left parietal infarction, but could correctly select shape, texture, and object stimuli more frequently than expected by chance.

A case of prosopometamorphopsia caused by infarction of the splenium of the corpus callosum and major forceps

An adult female complained of enlargement of right eyes in other people. Diffusion-weighted imaging detected an abnormal high-intensity area in the region from the splenium of the corpus callosum to the major forceps on the right side. The patient reported that right eyes appeared larger in size, which suggested prosopometamorphopsia. Adichotic listening test identified left-ear deficit. Acombination of prosopometamorphopsia and left-ear deficit was not identified in the reported patients. Prosopometamorphopsia in most of the reported patients included the eye as did that in our patient. This result suggested the importance of information on the eye in recognizing faces.

Increased Presence of Cerebral Microbleeds Correlates With Ventricular Enlargement and Increased White Matter Hyperintensities in Alzheimer's Disease

Objective: To investigate whether the number of cerebral microbleeds (CMB) could be a useful indicator to predict glymphatic system dysfunction in Alzheimer's disease (AD) patients, by comparing the degree of cerebral spinal fluid (CSF) and interstitial fluid (ISF) stasis. Methods: Forty probable AD patients were included, with those exhibiting two or more CMB were included in the multiple CMB group (mCMB, n = 21, mean = 11.1), and none or one CMB included in the non-multiple CMB group (nmCMB, n = 19, mean = 0.84). CMB was defined in axial gradient recalled echo (GRE) T2*-weighted images. Evans index (EI) was calculated to measure lateral ventricle enlargement, Voxel-based Specific Regional Analysis System for Alzheimer's Disease (VSRAD) software was used to determine the extent of gray and white matter atrophy, and Fazekas scale (FS) was used to determine white matter hyperintensities (WMH). Results: EI was significantly larger in mCMB than in nmCMB, while the gray and white matter volume was not different between groups. Thus, the difference in lateral ventricle enlargement between AD with and without multiple CMB reflects a combination of the degree of brain atrophy and the extent of CSF stasis. FS was higher in mCMB than in the nmCMB, suggesting the failure of ISF elimination was more severe in mCMB cases. Conclusion: The difference in lateral ventricle enlargement and WMH between AD with or without multiple CMB may reflect a difference in the degree of CSF/ISF stagnation.

Contraction of distance and duration production in autism spectrum disorder

Autism spectrum disorder (ASD) presents certain hallmark features associated with cognitive and social functions, however, the ability to estimate self-generated distance and duration in individuals with ASD are unclear. We compared the performance of 20 ASD individuals with 20 typical developments (TDs) with respect to two tasks: (1) the drawing of a line of a specified distance (10 or 20 cm) and (2) waiting for a specified time (10 or 20 s). We observed that both the line distances and waiting times were substantially shorter in the ASD group than in the TD group. Furthermore, a trait of "attention to detail," as measured by the Autism-Spectrum Quotient, correlated with some distance and duration productions observed in individuals with ASD. We suggest that attentional functions are related to the contraction of distance and duration in ASD.

The relationship between thyroid function and cerebral blood flow in mild cognitive impairment and Alzheimer's disease

The thyroid hormones have been reported to be associated with cognitive decline and Alzheimer’s disease. The relationship between thyroid function within the normal range and cerebral blood flow in Alzheimer’s disease patients has been shown in a recent study. Mild cognitive impairment is often the first stage of Alzheimer’s disease; thus, early diagnosis is important. The present study investigated the relationship between thyroid function and regional cerebral blood flow in patients with mild cognitive impairment and Alzheimer’s disease. A total of 122 memory clinic outpatients who underwent thyroid function testing and single photon emission computed tomography were divided into mild cognitive impairment, Alzheimer’s disease, and Normal groups. Regional cerebral blood flow was calculated using a three-dimensional stereotactic region of interest template in an automated cerebral perfusion single photon emission computed tomography analysis system. Multiple regression analysis adjusted for age and sex was conducted to examine the relationships between thyroid hormones and regional cerebral blood flow. Thyroid stimulating hormone was significantly associated with regional cerebral blood flow in the bilateral temporal, bilateral pericallosal, and bilateral hippocampal regions in the mild cognitive impairment group. In the Alzheimer’s disease group, free triiodothyronine was significantly associated with regional cerebral blood flow in the bilateral parietal, right temporal, and bilateral pericallosal regions. The present study showed the association of thyroid stimulating hormone with regional cerebral blood flow in the mild cognitive impairment group and the association of free triiodothyronine with regional cerebral blood flow in the Alzheimer’s disease group. These study findings could contribute to the early diagnosis of mild cognitive impairment at general memory clinics and the prevention of subsequent progression to Alzheimer’s disease.

High serum high-density lipoprotein-cholesterol is associated with memory function and gyrification of insular and frontal opercular cortex in an elderly memory-clinic population

The issue of whether serum lipid marker values are cognitively and neurologically significant for elderly individuals attending a memory clinic has been controversial. We investigated the associations of serum lipid markers with the memory function and cortical structure in 52 patients aged ≥75 years who had attended our memory clinic based on their subjective memory complaints. None had a history of medication for hyperlipidemia. The Wechsler Memory Scale-Revised (WMS-R) was administered to all patients for the assessment of their memory function. Serum low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDLC), and triglyceride (TG) were measured for each patient. Surface-based morphometry (SBM) was performed for the calculation of each patient's cortical thickness and gyrification index based on structural MRI data. Our analyses revealed that the serum HDLC level was positively and significantly correlated with the WMS-R subtests of visual paired associates I/II and logical memory I (p < 0.05). The serum TG level was negatively correlated with the logical memory I subtest. The SBM results showed positive correlations between the serum HDLC level and the gyrification indices of the bilateral insular and frontal opercular cortices, and those two gyrification indices were positively correlated with the logical memory I and visual paired associates I/II. These results suggest that in these elderly patients, a high serum HDLC level was associated with not only preserved memory function but also gyrification of the insular and frontal opercular cortex. We conclude that elderly individuals' serum lipid markers should be carefully assessed in memory clinic settings, because serum HDLC may be a biomarker for memory function and cortical structure.

Impaired cognitive modification for estimating time duration in Parkinson's disease

Parkinson's disease (PD) is associated with various cognitive impairments. However, the nature of cognitive modification in patients with PD remains to be elucidated. In the present study, we examined whether patients with PD could correct and maintain subjective time duration and line length estimation. After training sessions, in which participants repeatedly memorized either a duration or a length, we compared a learning performance in 20 PD patients with 20 healthy controls. In the case of duration in the PD patients, the learned durations immediately returned to baseline of pre-training within a few minutes. However, the patients’ ability to learn length estimation remained unimpaired. In contrast, healthy controls were able to retain the learned duration and length estimations. Time compression in PD's internal clock may become entrained to their altered duration estimation even after learning of accurate time duration. These deficits may be associated with disrupting cognitive modification in PD.

[Musical Hallucinosis]

Musical hallucination is one of the most complex forms of auditory hallucinations, where subjects perceive complex sound in the form of music, in the absence of an acoustic stimulus. It has been reported in patients with diseases such as psychiatric disorders, organic brain diseases, and epilepsy. However, the most common of these are idiopathic musical hallucinations that occur alongside deafness in the elderly. In recent years, there have been many reports of musical hallucination occurring as a result of mild cognitive impairment and dementia. Musical hallucinations accompanying hearing loss may reflect deterioration of cerebral function. It has been suggested that auditory Charles Bonnet syndrome is a pathophysiological mechanism of musical hallucination. The decrease in auditory stimulation and activation of the auditory network may activate the cerebral network in relation to music. It is also thought that musical hallucination appears from disintegration of the complementary relationship between sensation and memory. Treatment is still the focus of extensive investigation. Some authors have reported that hearing aids, antiepileptic drugs, anticholinergics, and antipsychotics can relieve musical hallucination. It is possible that such treatment may lead to relief of musical hallucination in patients with various background diseases. Population aging in Japan has exceeded 20%, which is the highest in the world; therefore, there may be many undiagnosed patients throughout the country.

Diagonistic Apraxia: A Unique Case of Corpus Callosal Disconnection Syndrome and Neuromyelitis Optica Spectrum Disorder

Diagonistic apraxia is a corpus callosal disconnection syndrome. Callosal lesions in Neuromyelitis optica spectrum disorder (NMOSD) have been reported, but callosal disconnection syndrome are rare. A 48-year-old woman was treated for fever and a cough before hospitalization. Her fever abated immediately, but she had balance problems in walking and standing. She also had slurred speech. On neurological examination, she had diagonistic apraxia. Her left hand moved in an uncoordinated way when she moved her right hand: changing her clothes for example or using a knife and fork. She had to instruct her left hand to stop. She had dysarthria and her gait was wide-based. She also had many callosal disconnection syndrome symptoms such as alexia of left visual field, left ear extinction, crossed optic ataxia. Using FLAIR and DWI MRI, a mixture of low and high signals, a so-called “marbled pattern,” was seen in the corpus callosum. Since the patient was positive for anti-aquaporin-4 antibody, she was diagnosed with NMOSD. After two courses of steroid pulse therapy, the symptoms improved. Here we report diagonistic apraxia and other symptoms of callosal disconnection syndrome in anti-AQP4-positive NMOSD.

Impairment of cross-modality of vision and olfaction in Parkinson disease

OBJECTIVE

To determine whether Parkinson disease (PD) affects cross-modal function of vision and olfaction because it is known that PD impairs various cognitive functions, including olfaction.

METHODS

We conducted behavioral experiments to identify the influence of PD on cross-modal function by contrasting patient performance with age-matched normal controls (NCs). We showed visual effects on the strength and preference of odor by manipulating semantic connections between picture/odorant pairs. In addition, we used brain imaging to identify the role of striatal presynaptic dopamine transporter (DaT) deficits.

RESULTS

We found that odor evaluation in participants with PD was unaffected by visual information, while NCs overestimated smell when sniffing odorless liquid while viewing pleasant/unpleasant visual cues. Furthermore, DaT deficit in striatum, for the posterior putamen in particular, correlated to few visual effects in participants with PD.

CONCLUSIONS

These findings suggest that PD impairs cross-modal function of vision/olfaction as a result of posterior putamen deficit. This cross-modal dysfunction may serve as the basis of a novel precursor assessment of PD.

Singular case of the driving instructor: Temporal and topographical disorientation

Lesions of the medio‐parietal lobes are linked with topographical and temporal disorientation, and are of interest to understanding mental time. We examined a 39‐year‐old man who worked as a driving instructor before cerebral hemorrhage, and followed his case for 8 years including neuropsychological testing and brain imaging. The patient had mild anterograde episodic amnesia, but no semantic amnesia. He felt that time passed too quickly, and developed a compulsive routine to compensate, although he was able to count time at a normal speed. Furthermore, he was unable to accurately sketch the layout of his house and to make a cross‐reference type timetable for the future. Brain magnetic resonance imaging showed lesions of the left anterior–posterior cingulate gyrus, and N‐isopropyl‐[¹²³I] p‐iodoamphetamine single‐photon emission computed tomography showed decreased blood flow mainly of the left medio‐parietal lobe.

The subjective perception of past, present, and future time in patients with Alzheimer's disease: a qualitative study

BACKGROUND

The relationship between dementia and time perception impairment is unknown.

AIM

This study aims to explore subjective perception of the passage of time in patients with Alzheimer's disease (AD).

METHODS

We conducted semi-structured interviews with 11 AD patients. Grounded theory, a qualitative research methodology, was used for data analysis.

RESULTS

Based on interview transcripts, five categories were designated: {Live according to a private clock}, {The past comes up}, {Move back and forth between the present and the past}, {Cannot imagine the future}, and {Bid farewell to this world as early as tomorrow}.

DISCUSSION

Our results suggest that AD patients alternate past and present without complete awareness and cannot imagine a future other than one ending in death.

Differential Effects of the Factor Structure of the Wechsler Memory Scale-Revised on the Cortical Thickness and Complexity of Patients Aged Over 75 Years in a Memory Clinic Setting

The Wechsler Memory Scale-Revised (WMS-R) is one of the internationally well-known batteries for memory assessment in a general memory clinic setting. Several factor structures of the WMS-R for patients aged under 74 have been proposed. However, little is known about the factor structure of the WMS-R for patients aged over 75 years and its neurological significance. Thus, we conducted exploratory factor analysis to determine the factor structure of the WMS-R for patients aged over 75 years in a memory clinic setting. Regional cerebral blood flow (rCBF) was calculated from single-photon emission computed tomography data. Cortical thickness and cortical fractal dimension, as the marker of cortical complexity, were calculated from high resolution magnetic resonance imaging data. We found that the four factors appeared to be the most appropriate solution to the model, including recognition memory, paired associate memory, visual-and-working memory, and attention as factors. Patients with mild cognitive impairments showed significantly higher factor scores for paired associate memory, visual-and-working memory, and attention than patients with Alzheimer's disease. Regarding the neuroimaging data, the factor scores for paired associate memory positively correlated with rCBF in the left pericallosal and hippocampal regions. Moreover, the factor score for paired associate memory showed most robust correlations with the cortical thickness in the limbic system, whereas the factor score for attention correlated with the cortical thickness in the bilateral precuneus. Furthermore, each factor score correlated with the cortical fractal dimension in the bilateral frontotemporal regions. Interestingly, the factor scores for the visual-and-working memory and attention selectively correlated with the cortical fractal dimension in the right posterior cingulate cortex and right precuneus cortex, respectively. These findings demonstrate that recognition memory, paired associate memory, visual-and-working memory, and attention can be crucial factors for interpreting the WMS-R results of elderly patients aged over 75 years in a memory clinic setting. Considering these findings, the results of WMS-R in elderly patients aged over 75 years in a memory clinic setting should be cautiously interpreted.

Accumulation of 123I-Ioflupane Is a Useful Marker of the Efficacy of Selegiline Monotherapy in Drug-Naïve Parkinson's Disease

Background: Selegiline enhances the patient's endogenous dopamine by inhibiting dopamine metabolism. The efficacy of selegiline monotherapy for drug-naïve Parkinson's disease (PD) patients may depend on the degree of dopaminergic neuronal degeneration. ¹²³I-Ioflupane single photon emission computed tomography (SPECT) and ¹²³I-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy are diagnostic methods to assess the pharmacological and pathological changes in PD. Objective: We examined the utility of these imaging methods to predict the efficacy of selegiline monotherapy for motor symptoms in drug-naïve PD patients. Methods: We observed the efficacy of selegiline monotherapy in 28 drug-naïve PD patients and compared the improvement in motor function and the imaging findings. These patients received selegiline monotherapy, and the amount was increased to the optimal dose in clinical practice. Motor function was assessed using the Unified Parkinson's Rating Scale (UPDRS) at baseline and at the stable dose. Imaging was performed before treatment, and the striatal Specific Binding Ratio (SBR) of the ¹²³I-Ioflupane SPECT and the Heart-to-Mediastinum (H/M) ratio of the ¹²³I-MIBG myocardial scintigraphy were calculated. Both ratios were compared with improvements in scores for motor assessment using Pearson's correlation coefficient. Results: The mean UPDRS part III score significantly improved with at least 5.0 mg/day of selegiline. Further dose escalation did not improve the mean motor score. The percent improvement in the motor score from baseline showed a significant negative correlation with the SBR of average of the right and left striatum, but not with the H/M ratio. Multiple regression analysis using patient's background factors showed that percent improvement in the UPDRS part III score directly correlate with the SBR (p = 0.04), but not with the age (p = 0.72), disease duration (p = 0.31), baseline UPDRS part III (p = 0.77) and the drug dose (p = 0.26). Conclusion: PD patients with a lower accumulation of ¹²³I-Ioflupane in the striatum can have greater improvement with selegiline monotherapy.

[Clocks, Behavior, and Cognition]

The nerve center responsible for controlling our circadian rhythm is located in a cluster of cells known as the suprachiasmatic nucleus in the hypothalamus. Various physiological functions such as sleep, arousal, blood pressure, body temperature, and hormone secretion are regulated in a 24-hour rhythm by this circuit. Somatic cells of other organs have a peripheral clock gene and by synchronizing the rhythm of the central and peripheral clocks, it is possible to live a healthy life. Due to aging and degenerative disease, circadian rhythm gradually collapses. Factors that can contribute to this include reduced expression of the time gene associated with photo stimulation, a reduction in neurotransmitter levels, and reduced melatonin production. Biological clocks play an important role in our emotions, cognitive function, and behavior. Sleep disorders and metabolic disease related to the circadian rhythm affect metabolic and endocrine activities via the autonomic nervous system and the intestinal bacterial flora. Shift work disorder is associated with insomnia and excessive drowsiness as individuals often work during their sleeping hours. Now time management is placed at the center of our society, and it is important to evaluate the medical risk of engaging in shift work. In frontotemporal dementia (FTD), the stereotypical behaviors may be associated with time. In some patients, multiple timed behaviors occupy a considerable part of the patient's daily life. Stereotypical behaviors in FTD are often considered in contrast to obsessive-compulsive disease (OCD). Studies of OCD have found a close correlation between clinical symptoms, cognitive function, and brain function.

Improvement in Language Function Correlates with Gait Improvement in Drug-naïve Parkinson's Disease Patients Taking Dopaminergic Medication

BACKGROUND

Dopaminergic drugs, the gold standard for motor symptoms, are known to affect cognitive function in Parkinson's disease (PD) patients.

OBJECTIVE

We compared the effects of dopaminergic treatment on motor and cognitive function in drug-naïve patients.

METHODS

Dopaminergic medication (levodopa, dopamine agonist, selegiline) was given to 27 drug-naïve PD patients and increased to a dose optimal for improved motor symptoms. Patients were tested prior to, and 4-7 months after, drug initiation. Motor function was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS). Cognitive function was assessed using both the Japanese version of the Montreal Cognitive Assessment (MoCA-J) and the Neurobehavioral Cognitive Status Examination (COGNISTAT-J). Improvements from baseline for both motor and cognitive assessment were compared.

RESULTS

Mean score of all motor assessments (UPDRS total score of Parts II and III, and sub-scores of tremor, rigidity, bradykinesia, gait, and postural instability) and certain cognitive assessments (MoCA-J total score and subscore of delayed recall) significantly improved with dopaminergic medication. Gait score improvement showed significant positive correlation with improvement in MoCA-J language domain and in language-comprehension subtests of COGNISTAT-J using Spearman's correlation coefficients. Furthermore, multiple regression analysis showed gait score improvement significantly correlated with improvements in the subtests of language-comprehension in COGNISTAT-J.

CONCLUSION

There is correlated improvement in both gait and language function in de novo PD patients in response to dopaminergic drugs. Gait and language dysfunction in these patients may share a common pathophysiology linked to dopamine deficits.

Dysfunctional counting of mental time in Parkinson's disease

Patients with Parkinson’s disease (PD) often underestimate time intervals, however it remains unclear why they underestimate rather than overestimate them. The current study examined time underestimation and counting in patients with PD, in relation to dopamine transporter (DaT) located on presynaptic nerve endings in the striatum. Nineteen non-dementia patients with PD and 20 age- and sex-matched healthy controls performed two time estimation tasks to produce or reproduce time intervals with counting in the head, to examine dysfunctional time counting processing. They also performed tapping tasks to measure cycles of counting with 1 s interval with time estimation. Compared to controls, patients underestimated time intervals above 10 s on time production not reproduction tasks, and the underestimation correlated with fast counting on the tapping task. Furthermore, striatal DaT protein levels strongly correlated with underestimation of time intervals. These findings suggest that distortion of time intervals is guided by cumulative output of fast cycle counting and that this is linked with striatal DaT protein deficit.

[Confabulation: From the Aspect of Disturbance in Time Perception]

Confabulation is a false story that amnesic patients make up unintentionally, by recollecting irrelevant memories instead of relevant. Disconnection of a brain network, including the diencephalon, basal forebrain, orbitofrontal, cortex and medial temporal lobe, could be the cause of this neuropsychological symptom. Considering confabulation from the aspect of disturbance in time perception is useful in understanding the mechanism of human time perception and the essence of confabulation.

Autobiographical age awareness disturbance syndrome in autoimmune limbic encephalitis: two case reports

Background

Autobiographical memory is a form of episodic memory characterized by a sense of time and consciousness that enables an individual to subjectively re-experience his or her past. As part of this mental re-enactment, the past is recognized relative to the present. Dysfunction of this memory system may lead to confusion regarding the present perception of time.

Case presentation

Two Japanese women (42 and 55 years old) temporarily believed they were living in their past during a course of autoimmune limbic encephalitis. Their autobiographical memories and behaviour reflected their self-estimated age, and they could not recall memories experienced beyond that age. More surprisingly, their subjective age estimations and autobiographical memories were transiently corrected when they were made aware of their true age. Disorientation, anterograde amnesia, and retrograde amnesia were common additional symptoms. Neuroimaging suggested disturbances in medial temporal and orbitofrontal brain regions in both cases.

Conclusions

This syndrome is characterized by three elements: 1) failure to subjectively recognize the present; 2) inability to suppress irrelevant past memories; and 3) transient restitution of awareness of the present through realization of the individual’s true age. We defined this syndrome as ‘autobiographical age awareness disturbance’, and focused our investigation on the role of age self-awareness. If recall of relevant and suppression of irrelevant past memories are both necessary to subjectively recognize the present relative to the past, dysfunction of medial temporal and orbitofrontal brain regions is predicted to lead to abnormal subjective placement in time. However, the subjective experience of age tends to be an important informational component for retrieving remote autobiographical memories. This suggests that correct age awareness is essential for the proper recognition of the remote past in relation to the present. This is the first report to focus on the relationship between subjective temporal orientation and age self-awareness. While the role of age awareness in this process is still unclear, investigating autobiographical age awareness disturbance as a part of subjective temporal awareness dysfunction can be useful in understanding the processes underlying human time recognition.

[Diabetes and Dementia]

An aging global population is driving the current epidemic of dementia and type 2 diabetes mellitus. Diabetes is a known risk factor for the development of vascular dementia, Alzheimer's disease, and mild cognitive impairment. Good control of diabetes may improve cognitive decline and prevent Alzheimer's disease. Mild cognitive impairment with type 2 diabetes (DM-MCI) often presents as a decline in attention, psychomotor speed, executive function, and memory. The Montreal Cognitive Assessment (MoCA) is one of the best screening tools for detecting DM-MCI. We found that 72% of the patients admitted to educational hospitalization for type 2 diabetes could also be categorized into groups with frontal lobe dysfunction, delayed recall, and a mixed-type group. Anti-diabetic drugs and insulin may protect and improve cognitive dysfunction in Alzheimer's disease and DM-MCI, but more studies are needed to verify this claim. Diabetes mellitus may be linked not only to Alzheimer's disease but also to other neurodegenerative diseases, such as Parkinson's, Huntington's and frontotemporal lobe dementia.

[Mental time dysfunction in Parkinson's and Alzheimer's diseases]

Mental time is altered by a number of factors and the underlying neural processing involved is highly complicated. Recent research suggests that mental time in patients with particular neurological diseases is perceptually shorter than in normal individuals. This review introduces mental time dysfunction and a model for processing of mental time in Parkinson's and Alzheimer's disease. Although the two diseases show the same dysfunction of mental time in behavior, we expect the underlying neural mechanism to vary in each disease. It is possible that the dysfunction of mental time in Parkinson's disease is caused by the abnormal striatum acting as a pacemaker, while that in Alzheimer's disease is caused by abnormal hippocampal memory.

[Successful treatment with anti-epileptic-drug of an 83-year-old man with musical hallucinosis]

An 83-year-old man with 3 years symptomatic hearing loss suddenly experienced musical hallucinosis. He heard children's songs, folk songs, military songs, and the Japanese national anthem for seven months every day. He sometime had paroxysmal nausea, dull headaches and depressive mood. On examination he had no psychosis or neurological symptoms except sensorineural hearing loss in both ears. MRI brain imaging and electroencephalography showed no significant abnormalities, however ¹²³I-IMP brain SPECT showed decreased activity in the right temporal lobe and increased activity in the left temporal and parietal lobes. Late phase ¹²³I-iomazenil brain SPECT showed decreased accumulation in the right temporal lobe compared to the early phase. This indicates right temporal lobe epilepsy. He was diagnosed with epilepsy because of paroxysmal nausea and headache and the laterality of ¹²³I-IMP brain SPECT and ¹²³I-iomazenil brain SPECT. The musical hallucinosis was much reduced by carbamazepine 200mg per day. Nine months after beginning carbamazepine we detected decreased activity in the right temporal lobe and increased activity in left temporal and parietal lobes was improved. We do not believe he had epileptogenic musical hallucinosis because his musical hallusinosis was neither paroxysmal nor lateral. We diagnosed auditory Charles Bonnet syndrome with onset 3 years after sensorineural hearing loss due to reversible epileptic like discharge in temporal and parietal lobes. There is no established treatment for musical hallucinosis, but anti-epileptic drugs may be of some help.

[Functional coupling of the frontal and parietal lobes in action]

Apraxia is the inability to perform actions or move different parts of the body in the intended manner, despite normal physical capability of movement. Based on his studies, Liepmann divided apraxia into three types: ideational apraxia, ideomotor apraxia, and limb-kinetic apraxia. Clinical findings such as ideomotor apraxia in Broca's area and apraxia in patients with Parkinson's disease (PD) and parietal ataxia suggest sensorimotor integration and action control in the parietofrontal circuits. Based on studies of the mirror neuron system, disorders in gesture production could be associated with disorders of gesture understanding. We recently reported ideomotor apraxia in association with lesions in Broca's area. Broca's area is the center of speech production, and also mediates action production. Although apraxia is not a typical clinical feature of PD, varying degrees of apraxia have been reported. The dysfunction of the motor and premotor areas, which send projections to the basal ganglia, causes this apraxia. Parietal ataxia is caused by lesions in the parietal lobe, which are thought to be caused by disconnection between the cerebellum and Brodmann area 5 in the parietal lobe.

Perceiving "ghost" images: a unique case of visual allesthesia with hemianopsia in mitochondrial disease

A 49-year-old man with mitochondrial disease presented with visual allesthesia, a rare and puzzling phenomenon. He was admitted for treatment because of convulsions. After the convulsions ceased, he exhibited left homonymous hemianopsia. Brain diffusion-weighted magnetic resonance imaging (MRI) showed a high-intensity area in the right occipital lobe. Both the hemianopsia and the MRI activation in this area disappeared by day 36 of hospitalization. On the morning of day 57, right homonymous hemianopsia emerged in a singular manner. The patient perceived an illusory object (a bottle placed by the bedside) in his left visual field, while the real object was in his blind right field. This case of visual allesthesia was accompanied by palinopsia, ie, perseveration of the image of the bottle. Diffusion-weighted MRI showed a new, high-intensity area in the left occipital lobe. We believe the visual allesthesia resulted from transfer of cortical information obtained by blindsight between hemispheres as a result of epileptic excitation.

A new disorder of praxis in neurodegenerative disease that may be part of Alzheimer's disease

Apraxia is a well-known disorder of praxis and is caused mainly by damage to the left parietal lobe. We presented two cases of neurodegenerative disease with a distinct disorder of praxis, predominantly involving left parietal lobe. While both patients could understand what they should do, they were not able to initiate action and often stopped during execution of actions. They had no apraxia and no temporal and spatial errors on praxis. Magnetic resonance imaging of both patients showed atrophy of the left parieto-occipital and temporo-occipital lobes, and single photon emission computed tomography showed hypoperfusion in the same lobes. Moreover, one of our cases, using [11C] PIB PET, demonstrated increased uptake in the cerebral cortices, suggesting Alzheimer's disease. The symptoms described are different from other disorders of praxis and similar to bradyphrenia or freezing.

[Mental time: a novel approach in neuropsychology]

Abstract Mental time is the cognitive conscious perception of past, present, and future. In this review we examine the novel research field of the neuropsychology of mental time in five ways. First, we review the mental time of amnesic patients. Second, we review reports of "Chronognosia". Third, we review confabulation associated with disturbance of mental time. Fourth, we present a new syndrome of mental time associated with "age awareness". Finally, we review concepts of prospective memory.

[Epilepsy and cognitive dysfunction]

Higher brain dysfunction is a major problems of epileptic patients. Epilepsy may cause transient epileptic higher brain dysfunctions like transient epileptic amnesia (TEA), or persistent epileptic higher brain dysfunction with or without findings of non-convulsive status epilepticus (NCSE). These are all defined as epilepsy with higher brain dysfunction (E-HBD). Amnesia, aphasia, or personality/behavior change are well known symptoms of E-HBD. Geshwind syndrome including personality changes seen in temporal epileptic patients, and Klüver-Bucy syndrome have also reported as a symptom of epilepsy. Anti-epileptic drugs (AEDs) are used to prevent convulsive or non-convulsive attacks, but it may cause higher brain dysfunction. Sedation, impairment of concentration or memory, and dizziness are frequently seen as cognitive side effects of AEDs. We review these higher brain dysfunctions in epileptic patients, and report a case of limbic encephalitis.

[Epilepsy with higher brain dysfunction]

Acquired higher brain dysfunction is for the most part due to cerebral vascular disease, but epilepsy may also be a cause. In this study with five patients, we discuss the advantages of anti-epileptic drugs (AEDs) for persistent higher brain dysfunction. The patients showed chronic amnesia or acute aphasia, with associated symptoms like personality change. All five cases affected automatism or convulsive attack, though only after the emergence of higher brain dysfunction and administration of AEDs. There were underlying diseases like cerebral arteriovenous malformation in four cases, but the other patient had none. Electroencephalogram and single photon emission computed tomography revealed one case of aphasia epilepsy with higher brain dysfunction. These results suggest the potential therapeutic efficacy of AEDs for persistent higher brain dysfunction, and we must differentiate epilepsy with higher brain dysfunction from dementia or cerebral vascular disease.

Is this a new type of primary prosopagnosia, both progressive and apperceptive?

Prosopagnosia, the inability to recognize faces, has a history going back to Charcot and Hughlings-Jackson, but was first named by Bodamer in 1947. Its anatomical loci are still unclear. However, progressive prosopagnosia is normally linked to right dominant temporal lobe atrophy, and diagnosed as part of frontotemporal lobar degeneration. Here we report a case of prosopagnosia linked to posterior cortical atrophy. Although case reports of posterior cortical atrophy-prosopagnosia do already exist, it is normally described as an accessory symptom. The interest of our own posterior cortical atrophy patient, possibly the first such case, is that he had a rare apperceptive type of prosopagnosia unrelated to the associative, frontotemporal lobar degeneration-type.

[Progressive visual agnosia]

Progressive visual agnosia was discovered in the 20th century following the discovery of classical non-progressive visual agnosia. In contrast to the classical type, which is caused by cerebral vascular disease or traumatic injury, progressive visual agnosia is a symptom of neurological degeneration. The condition of progressive visual loss, including visual agnosia, and posterior cerebral atrophy was named posterior cortical atrophy (PCA) by Benson et al. (1988). Progressive visual agnosia is also observed in semantic dementia (SD) and other degenerative diseases, but there is a difference in the subtype of visual agnosia associated with these diseases. Lissauer (1890) classified visual agnosia into apperceptive and associative types, and it in most cases, PCA is associated with the apperceptive type. However, SD patients exhibit symptoms of associative visual agnosia before changing to those of semantic memory disorder. Insights into progressive visual agnosia have helped us understand the visual system and discover how we "perceive" the outer world neuronally, with regard to consciousness. Although PCA is a type of atypical dementia, its diagnosis is important to enable patients to live better lives with appropriate functional support.