Multiple thalamo-cortical disconnections in anterior thalamic infarction: implications for thalamic mechanisms of memory and language.

Amnesia and linguistic deficits that are associated with thalamic damage have attracted the attention of researchers interested in identifying the neural networks involved in memory and language. The Papez circuit, which is composed of the hippocampus, mammillary body and anterior thalamic nuclei, was first proposed to be critical for memory. However, subsequently, the roles of the neural circuit consisting of the rhinal/parahippocampal cortices and the mediodorsal thalamic nuclei became evident. The ventral lateral nuclei or its adjacent structures have been found to be involved in semantic processing, but the specific neural circuits dedicated to language functions have not been identified. Anterior thalamic infarcts, which affect very circumscribed regions of the ventral anterior portion of the thalamus, often cause paradoxically prominent memory and language deficits. We conducted tractography analyses in 6 patients with left anterior thalamic infarcts to identify neural connections or circuits in which disruptions are associated with memory and language deficits in this condition. The current study demonstrated that the mammillothalamic tract, which connects the mammillary body with the anterior thalamic nuclei, and the anterior and inferior thalamic peduncles, which contain neural fibers that extend from several thalamic nuclei to the anterior temporal, medial temporal and frontal cortices, are disrupted in anterior thalamic infarction. These extensive thalamo-cortical disconnections appear to be due to the dissection of the neural fibers that penetrate the ventral anterior nucleus of the thalamus. Our results suggest the following: (1) amnesia that is associated with anterior thalamic infarction is best interpreted in the context of dual/multiple-system theories of memory/amnesia that posit that multiple neural circuits connecting the anterior and mediodorsal thalamic nuclei with the hippocampus and rhinal/parahippocampal cortices work in concert to support memory function; and (2) the semantic deficits observed in this syndrome may be associated with thalamo-anterior temporal and thalamo-lateral frontal disconnections.

Improvement in delusions and hallucinations in patients with dementia with Lewy bodies upon administration of yokukansan, a traditional Japanese medicine.

BACKGROUND: This multicentre open-label trial examined the efficacy and safety of the traditional Japanese medicine, or Kampo medicine, yokukansan (YKS), for behavioural and psychological symptoms of dementia (BPSD) in patients with dementia with Lewy bodies. METHODS: Sixty-three dementia with Lewy bodies patients with probable BPSD (M:W, 30:33; mean age, 78.2±5.8 years) were enrolled and treated with YKS for 4 weeks. RESULTS: Significant improvements in Neuropsychiatric Inventory scores (mean decrease, 12.5 points; P<0.001) and Zarit Burden Interview-Japanese edition tests (mean decrease, 3.6 points; P=0.024) were observed. In patients who consented to an assessment after 2 weeks of treatment, a time-dependent significant improvement was observed in the Neuropsychiatric Inventory score (n=23; mean decrease, 14.4; P<0.001), each subscale, including delusions and hallucinations, the Zarit Burden Interview-Japanese edition (n=22; mean decrease, 8.2; P<0.01) and the behavioural pathology in Alzheimer's disease insomnia subscale. The Mini-Mental State Examination and the Disability Assessment for Dementia (DAD) showed no significant change. Adverse events were observed in 11 (18%) patients. Three patients (5%) discontinued YKS due to adverse reactions, namely, spasticity and exacerbation of BPSD, edema, and nausea. Hypokalaemia (<3.5 mEq/L) was present in four patients (6%) at the study endpoint. Worsening of extrapyramidal symptoms was not observed. CONCLUSION: YKS improved BPSD in dementia with Lewy bodies patients and caregiver burden scores without deterioration in cognitive function. YKS is useful for the treatment of delusions and hallucinations in BPSD.

Neuroanatomy of a neurobehavioral disturbance in the left anterior thalamic infarction.

BACKGROUND AND PURPOSE: Cognitive and behavioural symptoms represent primary clinical manifestations of anterior thalamic infarcts (ATIs) in the tuberothalamic artery territory. The aim of the study is to understand the pathomechanism of cognitive and behavioural disturbances in left ATI (LATI). METHODS: 6 patients with isolated LATIs were investigated using neuropsychological assessments, MRI stereotactic lesion localisation and positron emission tomography. RESULTS: The patients were characterised clinically by verbal memory impairment, language disturbances dominated by anomia and word-finding difficulty and apathy. The ventral anterior nucleus (VA) proper, magnocellular VA (VAmc), ventral lateral anterior nucleus (VLa), ventral lateral posterior nucleus (VLp) and mammillothalamic tract were involved in all patients. Compared with healthy controls, the regional cerebral blood flow was lower in the thalamus, the dorsolateral, medial and orbital frontal lobes, the anterior temporal lobe, the inferior parietal lobule and the occipital lobe of the left hemisphere. CONCLUSIONS: The authors propose that the Papez circuit disruption at the mammillothalamic tract and possibly thalamomedial temporal disconnection at the VA region is responsible for memory impairment and that the thalamo-anterior temporal disconnection is associated with language disturbance in LATI, respectively.

Effectiveness of a clinical pathway for the diagnosis and treatment of dementia and for the education of families.

AIMS: Clinical pathways (CPs) are rarely used in the treatment of dementia. We established a CP for a series of medical practices (diagnosis, treatment, establishment of a care system, and caregiver education) for patients with dementia hospitalized for a three-week period, and evaluated its usefulness. METHODS: The length of hospital stay and hospital costs were compared between 23 consecutive patients with dementia hospitalized and treated using a CP and 20 controls treated by conventional medical practice without using a CP in a special ward for dementia patients. In the CP group, at the time of discharge, primary caregivers, physicians, and nurses were given a questionnaire to obtain their comments about the impression of treatment with the CP. RESULTS: The questionnaire survey indicated that the CP deepened the caregiver's understanding of the sequence of medical practices for the inpatient, the disorders of the inpatient, the treatment methods, and the methods for coping with the disorder. The CP was also useful for facilitating inpatient medical practice and promoting the establishment of a care system after discharge. The use of the CP significantly shortened the length of hospital stay and decreased hospital costs during hospitalization but increased the amount of work per day and made the medical staff feel that their freedom to choose medical procedures had been restricted. CONCLUSIONS: The CP was useful for execution of inpatient medical practices for patients with dementia.