'Communication is difficult': Speech, language and communication needs of people with young onset or rarer forms of non-language led dementia.

BACKGROUND: People with behavioural variant frontotemporal dementia, Lewy body dementia, posterior cortical atrophy and young onset Alzheimer's disease may experience language and communication difficulties. However, the role of speech and language interventions for people with these non-language led dementias has received little attention. AIMS: This study aimed to explore the experiences and perspectives of people living with these conditions, and their families, regarding their language and communication difficulties and how speech and language therapy could address these needs. METHODS: This study employed a qualitative design to explore the experiences of people living with or caring for somebody with behavioural variant frontotemporal dementia, Lewy body dementia, posterior cortical atrophy or young onset Alzheimer's disease, and to understand their opinions about speech and language therapy. Participants were recruited from a support service connected to a dementia clinic to attend one of five focus group meetings. Videorecorded focus groups and interviews were transcribed, and reflexive thematic analysis was used to analyse data from people affected by each type of dementia. RESULTS: A total of 25 participants were recruited to the study, with representation across the different forms of non-language led dementias. The four main themes identified were: (1) communication difficulties as a key difficulty, (2) loss and loneliness, (3) speech and language therapy, and (4) the role of the caregiver. Sixteen subthemes were also identified which highlighted individual issues across disease types. DISCUSSION: Although all the forms of dementia studied here are not considered to be language-led, people with these conditions and/or their care partners identified speech, language and communication as common challenges. These communication difficulties were reported to have a negative impact on their social participation and mental health and participants felt speech and language interventions could help. There is a need for research exploring speech and language interventions developed for and with people with non-language led dementias and their care partners, to ensure they meet the needs of the people they are designed for. WHAT THIS PAPER ADDS: What is already known on the subject People with primary progressive aphasia present with speech, language and communication difficulties, and several speech and language interventions have been developed to meet the needs of this population. However, people with non-language led dementias may also experience speech, language and communication difficulties, and little is known about interventions that may address these difficulties. What this paper adds to existing knowledge People living with or caring for somebody with behavioural variant frontotemporal dementia, Lewy body dementia, posterior cortical atrophy and young onset Alzheimer's disease report experiencing speech, language and communication difficulties that impact on the person with dementia's social participation and mood. Participants in this study also shared their opinions about how speech and language interventions could help, from the earliest stages of the disease. What are the potential or actual clinical implications of this work? Speech and language therapists need to address the individual speech, language and communication needs of people with dementias, even those that are not thought to be language-led. Current speech and language therapy service provision does not meet the needs of people with non-language led dementias and further research is required to develop interventions and services to meet these needs.

Clinical effectiveness of the START (STrAtegies for RelaTives) psychological intervention for family carers and the effects on the cost of care for people with dementia: 6-year follow-up of a randomised controlled trial.

BACKGROUND: The START (STrAtegies for RelaTives) intervention reduced depressive and anxiety symptoms of family carers of relatives with dementia at home over 2 years and was cost-effective. AIMS: To assess the clinical effectiveness over 6 years and the impact on costs and care home admission. METHOD: We conducted a randomised, parallel group, superiority trial recruiting from 4 November 2009 to 8 June 2011 with 6-year follow-up (trial registration: ISCTRN 70017938). A total of 260 self-identified family carers of people with dementia were randomised 2:1 to START, an eight-session manual-based coping intervention delivered by supervised psychology graduates, or to treatment as usual (TAU). The primary outcome was affective symptoms (Hospital Anxiety and Depression Scale, total score (HADS-T)). Secondary outcomes included patient and carer service costs and care home admission. RESULTS: In total, 222 (85.4%) of 173 carers randomised to START and 87 to TAU were included in the 6-year clinical efficacy analysis. Over 72 months, compared with TAU, the intervention group had improved scores on HADS-T (adjusted mean difference -2.00 points, 95% CI -3.38 to -0.63). Patient-related costs (START versus TAU, respectively: median £5759 v. £16 964 in the final year; P = 0.07) and carer-related costs (median £377 v. £274 in the final year) were not significantly different between groups nor were group differences in time until care home (intensity ratio START:TAU was 0.88, 95% CI 0.58-1.35). CONCLUSIONS: START is clinically effective and this effect lasts for 6 years without increasing costs. This is the first intervention with such a long-term clinical and possible economic benefit and has potential to make a difference to individual carers. DECLARATIONS OF INTEREST: G.L., Z.W. and C.C. are supported by the UCLH National Institute for Health Research (NIHR) Biomedical Research Centre. G.L. and P.R. were in part supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) North Thames at Bart's Health NHS Trust. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. Z.W. reports during the conduct of the study; personal fees from GE Healthcare, grants from GE Healthcare, grants from Lundbeck, other from GE Healthcare, outside the submitted work.

Motor signatures of emotional reactivity in frontotemporal dementia.

Automatic motor mimicry is essential to the normal processing of perceived emotion, and disrupted automatic imitation might underpin socio-emotional deficits in neurodegenerative diseases, particularly the frontotemporal dementias. However, the pathophysiology of emotional reactivity in these diseases has not been elucidated. We studied facial electromyographic responses during emotion identification on viewing videos of dynamic facial expressions in 37 patients representing canonical frontotemporal dementia syndromes versus 21 healthy older individuals. Neuroanatomical associations of emotional expression identification accuracy and facial muscle reactivity were assessed using voxel-based morphometry. Controls showed characteristic profiles of automatic imitation, and this response predicted correct emotion identification. Automatic imitation was reduced in the behavioural and right temporal variant groups, while the normal coupling between imitation and correct identification was lost in the right temporal and semantic variant groups. Grey matter correlates of emotion identification and imitation were delineated within a distributed network including primary visual and motor, prefrontal, insular, anterior temporal and temporo-occipital junctional areas, with common involvement of supplementary motor cortex across syndromes. Impaired emotional mimesis may be a core mechanism of disordered emotional signal understanding and reactivity in frontotemporal dementia, with implications for the development of novel physiological biomarkers of socio-emotional dysfunction in these diseases.

Detecting Memory Impairment in Deaf People: A New Test of Verbal Learning and Memory in British Sign Language.

OBJECTIVE: Most existing tests of memory and verbal learning in adults were created for spoken languages, and are unsuitable for assessing deaf people who rely on signed languages. In response to this need for sign language measures, the British Sign Language Verbal Learning and Memory Test (BSL-VLMT) was developed. It follows the format of the English language Hopkins Verbal Learning Test Revised, using standardized video-presentation with novel stimuli and instructions wholly in British Sign Language, and no English language requirement. METHOD: Data were collected from 223 cognitively healthy deaf signers aged 50-89 and 12 deaf patients diagnosed with dementia. Normative data percentiles were derived for clinical use, and receiver-operating characteristic curves computed to explore the clinical potential and diagnostic sensitivity and specificity. RESULTS: The test showed good discrimination between the normative and clinical samples, providing preliminary evidence of clinical utility for identifying learning and memory impairment in older deaf signers with neurodegeneration. CONCLUSIONS: This innovative video testing approach transforms the ability to accurately detect memory impairments in deaf people and avoids the problems of using interpreters, with international potential for adapting similar tests into other signed languages.

Quality improvement: audio-visual tools are a valuable supplement when obtaining consent for lumbar punctures.

Neurological conditions present a challenge when obtaining consent for lumbar punctures (LPs), as patients often have -visual, hearing or cognitive impairments. The aim of this -project was to improve the quality of the consent process for LPs. Surveys of doctors and patients suggested there was scope to standardise and improve information provided during the consent process. A patient information video was -developed using online software and shown to patients using tablet -computers. Patient surveys were distributed to re-assess the quality of the process for obtaining consent. There was a -significant improvement (p=0.031) in the median response score after the video was presented to the same group of patients. The use of patient information videos -significantly improves understanding and recall of the procedure, and -satisfaction with the consent process. In conclusion, audio--visual tools are a valuable tool for standardising and -improving the process of gaining consent for LPs.

Dissecting IWG-2 typical and atypical Alzheimer's disease: insights from cerebrospinal fluid analysis.

Pathobiological factors underlying phenotypic diversity in Alzheimer's disease (AD) are incompletely understood. We used an extended cerebrospinal fluid (CSF) panel to explore differences between "typical" with "atypical" AD and between amnestic, posterior cortical atrophy, logopenic aphasia and frontal variants. We included 97 subjects fulfilling International Working Group-2 research criteria for AD of whom 61 had "typical" AD and 36 "atypical" syndromes, and 30 controls. CSF biomarkers included total tau (T-tau), phosphorylated tau (P-tau), amyloid ß1-42, amyloid ßX-38/40/42, YKL-40, neurofilament light (NFL), and amyloid precursor proteins α and ß. The typical and atypical groups were matched for age, sex, severity and rate of cognitive decline and had similar biomarker profiles, with the exception of NFL which was higher in the atypical group (p = 0.03). Sub-classifying the atypical group into its constituent clinical syndromes, posterior cortical atrophy was associated with the lowest T-tau [604.4 (436.8-675.8) pg/mL], P-tau (79.8 ± 21.8 pg/L), T-tau/Aß1-42 ratio [2.3 (1.4-2.6)], AßX-40/X-42 ratio (22.1 ± 5.8) and rate of cognitive decline [1.9 (0.75-4.25) MMSE points/year]. Conversely, the frontal variant group had the highest levels of T-tau [1185.4 (591.7-1329.3) pg/mL], P-tau (116.4 ± 45.4 pg/L), T-tau/Aß1-42 ratio [5.2 (3.3-6.9)] and AßX-40/X-42 ratio (27.9 ± 7.5), and rate of cognitive decline. Whilst on a group level IWG-2 "typical" and "atypical" AD share similar CSF profiles, which are very different from controls, atypical AD is a heterogeneous entity with evidence for subtle differences in amyloid processing and neurodegeneration between different clinical syndromes. These findings also have practical implications for the interpretation of clinical CSF biomarker results.

Detecting Cognitive Impairment and Dementia in Deaf People: The British Sign Language Cognitive Screening Test.

To provide accurate diagnostic screening of deaf people who use signed communication, cognitive tests must be devised in signed languages with normative deaf samples. This article describes the development of the first screening test for the detection of cognitive impairment and dementia in deaf signers. The British Sign Language Cognitive Screening Test uses standardized video administration to screen cognition using signed, rather than spoken or written, instructions and a large norm-referenced sample of 226 deaf older people. Percentiles are provided for clinical comparison. The tests showed good reliability, content validity, and correlation with age, intellectual ability, and education. Clinical discrimination was shown between the normative sample and 14 deaf patients with dementia. This innovative testing approach transforms the ability to detect dementia in deaf people, avoids the difficulties of using an interpreter, and enables culturally and linguistically sensitive assessment of deaf signers, with international potential for adaptation into other signed languages.

START (STrAtegies for RelaTives) study: a pragmatic randomised controlled trial to determine the clinical effectiveness and cost-effectiveness of a manual-based coping strategy programme in promoting the mental health of carers of people with dementia.

BACKGROUND: Two-thirds of people with dementia live at home, receiving most care from family carers, about 40% of whom have clinically significant depression or anxiety. This impacts on the person with dementia, families and society, predicting care breakdown. There are currently no clinically effective and cost-effective NHS family carer interventions. OBJECTIVES: To assess the STrAtegies for RelaTives (START) intervention in the short (4 and 8 months) and long term (1 and 2 years) compared with treatment as usual (TAU). DESIGN: Randomised, parallel-group, superiority trial with blinded assessment recruiting participants 2:1 (intervention to TAU) to allow for therapist clustering. SETTING: Three UK mental health services and one neurological service. PARTICIPANTS: Family carers of people with dementia. INTERVENTION: Eight-session manual-based coping intervention delivered by supervised psychology graduates to individuals. MAIN OUTCOME MEASURES: Affective symptoms [Hospital Anxiety and Depression Scale-total (HADS-T)] and cost-effectiveness. Secondary measures: anxiety and depression symptoms and caseness, quality of life (QoL), abusive behaviour and long-term care home admission. RESULTS: Two hundred and sixty participants were randomised (173 intervention, 87 TAU). We used intention-to-treat analysis in the short term (152 intervention, 77 TAU) and in the long term (140 intervention, 69 TAU). In the short term, the intervention group had lower HADS-T [mean difference -1.80, 95% confidence interval (CI) -3.29 to -0.31; p=0.02] and higher quality-adjusted life-years (QALYs) (mean difference 0.03, 95% CI -0.01 to 0.08). Costs were no different between groups [mean £ 252 (95% CI -£ 28 to £ 565) for intervention group]. The cost-effectiveness acceptability curve showed a greater than 99% chance of being cost-effectiveness at a £ 30,000/QALY willingness-to-pay threshold and a high probability of cost-effectiveness based on the HADS-T score. Carers in the intervention group had less case-level depression [odds ratio (OR) 0.24, 95% CI 0.07 to 0.76], a trend towards reduced case-level anxiety (OR 0.30, 95% CI 0.08 to 1.05), lower Hospital Anxiety and Depression Scale-anxiety (HADS-A) (-0.91, 95% CI -1.76 to -0.07; p = 0.03) and Hospital Anxiety and Depression Scale-depression (HADS-D) (-0.91, 95% CI -1.71 to -0.10; p = 0.03) and higher Health Status Questionnaire (HSQ) QoL (mean difference 4.09, 95% CI 0.34 to 7.83). Group differences in abusive behaviour (OR 0.48, 95% CI 0.18 to 1.27) and the person with dementia's quality of life-Alzheimer's disease (QoL-AD) (mean increase 0.59, 95% CI -0.72 to 1.89) were not significant. In the long term, the intervention group had lower HADS-T (mean difference -2.58, 95% CI -4.26 to -0.90; p = 0.03) and higher QALYs (mean difference 0.03, 95% CI -0.01 to 0.06). Carers in the intervention group had less case-level depression (OR 0.14, 95% CI 0.04 to 0.53), a trend towards reduced case-level anxiety (OR 0.57, 95% CI 0.26 to 1.24), lower HADS-A (-1.16, 95% CI -2.15 to -0.18) and HADS-D (1.45, 95% CI -2.32 to -0.57), and higher HSQ (mean difference 7.47, 95% CI 2.87 to 12.08). Thirty-two (18.7%) people with dementia in the intervention group and 17 (20.2%) in TAU were admitted to a care home (hazard ratio 0.83, 95% CI 0.44 to 1.56; p = 0.56). There were no significant differences between groups in abusive behaviour (OR 0.83, 95% CI 0.36 to 1.94), the person with dementia's QoL-AD (0.17, 95% CI -1.37 to 1.70) or costs (£ 336, 95% CI -£ 223 to £ 895) for intervention group. The probability that the intervention would be seen as cost-effective at £ 30,000/QALY threshold and cost-effectiveness on the HADS-T remained high. CONCLUSIONS: The START intervention was clinically effective and cost-effective in the short and longer term. The results are robust to the sensitivity analyses performed. Future work is needed to consider mechanism of action; the effects on people with dementia in clinical terms (cognition, neuropsychiatric symptoms, longer-term care home admission); and on health and social care costs. In addition, we will explore the effects of carer abusive behaviour on the care recipient's care home admission and if this then reduces abusive behaviour. We would also like to implement START and evaluate this implementation in clinical practice. TRIAL REGISTRATION: Current Controlled Trials ISCTRN70017938.

Long-term clinical and cost-effectiveness of psychological intervention for family carers of people with dementia: a single-blind, randomised, controlled trial.

BACKGROUND: Two-thirds of people with dementia live at home supported mainly by family carers. These carers frequently develop clinical depression or anxiety, which predicts care breakdown. We aimed to assess the clinical effectiveness (long-term reduction of depression and anxiety symptoms in family carers) and cost-effectiveness of a psychological intervention called START (STrAtegies for RelaTives). METHODS: We did a randomised, parallel-group trial with masked outcome assessments in three UK mental-health services and one neurological-outpatient dementia service. We included self-identified family carers of people with dementia who had been referred in the previous year and gave support at least once per week to the person with dementia. We randomly assigned these carers, via an online computer-generated randomisation system from an independent clinical trials unit, to either START, an 8-session, manual-based coping intervention delivered by supervised psychology graduates, or treatment as usual (TAU). The primary long-term outcomes were affective symptoms (Hospital Anxiety and Depression Scale total score [HADS-T]) 2 years after randomisation and cost-effectiveness (health and social care perspectives) over 24 months. Analysis was by intention to treat, excluding carers with data missing at both 12 and 24 months. This trial is registered ISCTRN70017938. FINDINGS: From November 4, 2009, to June 8, 2011, we recruited 260 carers. 173 carers were randomly assigned to START and 87 to TAU. Of these 260 participants, 209 (80%) were included in the clinical efficacy analysis (140 START, 69 TAU). At 24 months, compared with TAU the START group was significantly better for HADS-T (mean difference -2·58 points, 95% CI -4·26 to -0·90; p=0·003). The intervention is cost effective for both carers and patients (67% probability of cost-effectiveness at the £20 000 per QALY willingness-to-pay threshold, and 70% at the £30 000 threshold). INTERPRETATION: START is clinically effective, improving carer mood and anxiety levels for 2 years. Carers in the control TAU group were seven times more likely to have clinically significant depression than those receiving START. START is cost effective with respect to carer and patient outcomes, and National Institute for Health and Care Excellence (NICE) thresholds. The number of people with dementia is rapidly growing, and policy frameworks assume that their families will remain the frontline providers of (unpaid) support. This cost-neutral intervention, which substantially improves family-carers' mental health and quality of life, should therefore be widely available. FUNDING: National Institute for Health Research Health Technology Assessment programme 08/14/06.

Clinical effectiveness of a manual based coping strategy programme (START, STrAtegies for RelaTives) in promoting the mental health of carers of family members with dementia: pragmatic randomised controlled trial.

OBJECTIVE: To assess whether a manual based coping strategy compared with treatment as usual reduces depression and anxiety symptoms in carers of family members with dementia. DESIGN: Randomised, parallel group, superiority trial. SETTING: Three mental health community services and one neurological outpatient dementia service in London and Essex, UK. PARTICIPANTS: 260 carers of family members with dementia. INTERVENTION: A manual based coping intervention comprising eight sessions and delivered by supervised psychology graduates to carers of family members with dementia. The programme consisted of psychoeducation about dementia, carers' stress, and where to get emotional support; understanding behaviours of the family member being cared for, and behavioural management techniques; changing unhelpful thoughts; promoting acceptance; assertive communication; relaxation; planning for the future; increasing pleasant activities; and maintaining skills learnt. Carers practised these techniques at home, using the manual and relaxation CDs. MAIN OUTCOME MEASURES: Affective symptoms (hospital anxiety and depression total score) at four and eight months. Secondary outcomes were depression and anxiety caseness on the hospital anxiety and depression scale; quality of life of both the carer (health status questionnaire, mental health) and the recipient of care (quality of life-Alzheimer's disease); and potentially abusive behaviour by the carer towards the recipient of care (modified conflict tactics scale). RESULTS: 260 carers were recruited; 173 were randomised to the intervention and 87 to treatment as usual. Mean total scores on the hospital anxiety and depression scale were lower in the intervention group than in the treatment as usual group over the eight month evaluation period: adjusted difference in means -1.80 points (95% confidence interval -3.29 to -0.31; P=0.02) and absolute difference in means -2.0 points. Carers in the intervention group were less likely to have case level depression (odds ratio 0.24, 95% confidence interval 0.07 to 0.76) and there was a non-significant trend towards reduced case level anxiety (0.30, 0.08 to 1.05). Carers' quality of life was higher in the intervention group (difference in means 4.09, 95% confidence interval 0.34 to 7.83) but not for the recipient of care (difference in means 0.59, -0.72 to 1.89). Carers in the intervention group reported less abusive behaviour towards the recipient of care compared with those in the treatment as usual group (odds ratio 0.47, 95% confidence interval 0.18 to 1.23), although this was not significant. CONCLUSIONS: A manual based coping strategy was effective in reducing affective symptoms and case level depression in carers of family members with dementia. The carers' quality of life also improved. TRIAL REGISTRATION: Current Controlled Trials ISCTRN70017938.

Cost effectiveness of a manual based coping strategy programme in promoting the mental health of family carers of people with dementia (the START (STrAtegies for RelaTives) study): a pragmatic randomised controlled trial.

OBJECTIVE: To assess whether the START (STrAtegies for RelatTives) intervention added to treatment as usual is cost effective compared with usual treatment alone. DESIGN: Cost effectiveness analysis nested within a pragmatic randomised controlled trial. SETTING: Three mental health and one neurological outpatient dementia service in London and Essex, UK. PARTICIPANTS: Family carers of people with dementia. INTERVENTION: Eight session, manual based, coping intervention delivered by supervised psychology graduates to family carers of people with dementia added to usual treatment, compared with usual treatment alone. PRIMARY OUTCOME MEASURES: Costs measured from a health and social care perspective were analysed alongside the Hospital Anxiety and Depression Scale total score (HADS-T) of affective symptoms and quality adjusted life years (QALYs) in cost effectiveness analyses over eight months from baseline. RESULTS: Of the 260 participants recruited to the study, 173 were randomised to the START intervention, and 87 to usual treatment alone. Mean HADS-T scores were lower in the intervention group than the usual treatment group over the 8 month evaluation period (mean difference -1.79 (95% CI -3.32 to -0.33)), indicating better outcomes associated with the START intervention. There was a small improvement in health related quality of life as measured by QALYs (0.03 (-0.01 to 0.08)). Costs were no different between the intervention and usual treatment groups (£252 (-28 to 565) higher for START group). The cost effectiveness calculations suggested that START had a greater than 99% chance of being cost effective compared with usual treatment alone at a willingness to pay threshold of £30,000 per QALY gained, and a high probability of cost effectiveness on the HADS-T measure. CONCLUSIONS: The manual based coping intervention START, when added to treatment as usual, was cost effective compared with treatment as usual alone by reference to both outcome measures (affective symptoms for family carers, and carer based QALYs). TRIAL REGISTRATION: ISCTRN 70017938.

Rituximab in the treatment of three coexistent neurological autoimmune diseases: chronic inflammatory demyelinating polyradiculoneuropathy, Morvan syndrome and myasthenia gravis.

A 76-year-old man with a pre-existing diagnosis of myasthenia gravis was admitted to an intensive care unit with pneumonia and type II respiratory failure. In addition, muscle weakness, widespread myokymia, neuropsychiatric disturbance and autonomic disturbance were present. Antivoltage gated potassium channel antibodies, antistriated muscle antibodies and antiacetylcholine receptor antibodies were positive. Nerve-conduction studies demonstrated findings consistent with patchy demyelination. Electromyography confirmed widespread myokymia, and there was evidence of diffuse encephalopathy on electroencephalography. Diagnoses of Morvan syndrome and chronic inflammatory demyelinating polyradiculopathy (CIDP) were made. Treatment with intravenous immunoglobulin, plasma exchange and high-dose steroids were ineffective, and the patient remained dependent on mechanical ventilation. The coexistence of possibly three humorally mediated autoimmune diseases led to treatment with rituximab. Rituximab treatment was followed by an improvement in muscle strength, allowing successful weaning from mechanical ventilation, diminution in myokymia and improved cognition. At follow-up, there was reversal of the neuropsychiatric manifestations and normal muscle strength. This case suggests that rituximab may be useful in the treatment of autoimmune neurological disease refractory to other immunosuppressant therapies. Specifically, it adds further evidence for the use of rituximab in CIDP. As indications for rituximab in humorally mediated disease continue to expand, international multicentre randomised controlled trials are required to prove the effectiveness of this important emerging biological agent.

Progressive logopenic/phonological aphasia: erosion of the language network.

The primary progressive aphasias (PPA) are paradigmatic disorders of language network breakdown associated with focal degeneration of the left cerebral hemisphere. Here we addressed brain correlates of PPA in a detailed neuroanatomical analysis of the third canonical syndrome of PPA, logopenic/phonological aphasia (LPA), in relation to the more widely studied clinico-anatomical syndromes of semantic dementia (SD) and progressive nonfluent aphasia (PNFA). 32 PPA patients (9 SD, 14 PNFA, 9 LPA) and 18 cognitively normal controls had volumetric brain MRI with regional volumetry, cortical thickness, grey and white matter voxel-based morphometry analyses. Five of nine patients with LPA had cerebrospinal fluid biomarkers consistent with Alzheimer (AD) pathology (AD-PPA) and 2/9 patients had progranulin (GRN) mutations (GRN-PPA). The LPA group had tissue loss in a widespread left hemisphere network. Compared with PNFA and SD, the LPA group had more extensive involvement of grey matter in posterior temporal and parietal cortices and long association white matter tracts. Overlapping but distinct networks were involved in the AD-PPA and GRN-PPA subgroups, with more anterior temporal lobe involvement in GRN-PPA. The importance of these findings is threefold: firstly, the clinico-anatomical entity of LPA has a profile of brain damage that is complementary to the network-based disorders of SD and PNFA; secondly, the core phonological processing deficit in LPA is likely to arise from temporo-parietal junction damage but disease spread occurs through the dorsal language network (and in GRN-PPA, also the ventral language network); and finally, GRN mutations provide a specific molecular substrate for language network dysfunction.

Temporal lobe lesions and semantic impairment: a comparison of herpes simplex virus encephalitis and semantic dementia.

Both herpes simplex virus encephalitis (HSVE) and semantic dementia (SD) typically affect anterior temporal lobe structures. Using voxel-based morphometry (VBM), this study compared the structural damage in four HSVE patients having a semantic deficit particularly affecting knowledge of living things and six SD patients with semantic impairment across all categories tested. Each patient was assessed relative to a group of control subjects. In both patient groups, left anterior temporal damage extended into the amygdala. In patients with HSVE, extensive grey matter loss was observed predominantly in the medial parts of the anterior temporal cortices bilaterally in SD patients the abnormalities extended more laterally and posteriorly in either the left, right or both temporal lobes. Based on a lesion deficit rationale and converging results from several other sources of evidence, we suggest that (i) antero-medial temporal cortex may be important for processing and differentiating between concepts that are 'tightly packed' in semantic space, such as living things, whereas (ii) inferolateral temporal cortex may play a more general role within the semantic system.