Anatomy and function of the Nervous System for Speech

Common Types of neurogenic voice disorders

o Central Nervous System (within bone):中枢神经系统

* Cerebrum大脑

* Cerebellum小脑

* Brainstem脑干

* Spinal Cord脊髓o Peripheral Nervous System 周围神经系统

(outside bone):

* 12 pairs of Cranial Nerves12对脑神经

* 31 pairs of Spinal Nerves 31对脊神经

* Sensory Receptors 感受器

Efferent connections of cortex frontal lobe 额叶大脑皮层传出结构

Basal ganglia 基底神经节 Cerebellum 小脑

Descending pathways to motor nuclei of cranial and spinal nerve 脑及脊神经运动核的下行通路

Efferent fibers within cranial and spinal nerves 脑及脊神经内的传出纤维

Striated muscle 横纹肌

Final common pathway 终端通路 Direct activation pathway 直接运动通路

Indirect activation pathway 间接运动通路

Control circuits 控制回路

Paired cranial nerves supplying muscles involved in phonation, resonance, articulation and prosody. 12对脑神经控制发声、共鸣、构音和音律方面的肌肉

Paired spinal nerves involved in respiratory activities. 31对脊神经参与呼吸方面的运动

Upper motor neuron system 上运动神经元系统 Corticobulbar tract: influence

activities of cranial nerves 皮质延髓束：影响脑神经的活动

Corticospinal tract : influence activities of spinal nerves

皮层脊髓束：影响脊神经的活动

part of the Pyramidal Pathways goes from the cortex to the spinal cord provides innervation for skeletal

muscles made up of over 1 million fibers which

arise from the cerebral cortex and other motor areas of the brain

also responsible for inhibition of reflexes Lesions on this tract would cause

Muscle weakness Loss of voluntary use of muscles Loss of muscle tone

Babinski Reflex Natural reflexes that we have as infants that

go away with time

is NOT a tract of the spinal cord very important for speech production arises from the premotor and

somesthetic (body sense) regions of the parietal lobe of the cortex

enters the brainstem provides innervation to many muscles

of the face, neck, pharynx and larynx

Reticular formation（网状结构）： Mediate consciousness, some portions excite extensor(伸肌 ) motoneurons and inhibit

flexor(屈肌 ) motoneurons other portions inhibit extensor motoneurons and excite flexors.

Corticoreticular tract

Vestibular nuclei（前庭神经核）： modulate the activities of the eye and neck muscles. Vestibulospinal tract facilitate reflex activity and control muscle

tone.

Red nuclei（红核）： Corticorubral tract and rubrospinal tract, influence flexor muscle

groups on the limbs.

Function: regular reflexes and posture, tone, and associated activities

that provide a framework on which the direct activation pathway can accomplish skills, discrete actions.

Effects of damage: Lesions above the midbrain and red nucleus produce increased

extensor tone in the legs and increased flexor tone in the arms. lesions below red nucleus produce a generalized increase in

extensor tone. Lesion below medulla produce generalized flaccidity in muscles.

UMN lesions include direct and indirect activation pathway.

Do not have direct contact with LMN. Basal ganglia control circuit

Cerebellar control circuit

Influence movement through cerebral cortex

Basal ganglia: caudate nucleus（尾状核） , putamen（豆状核） and globus pallidus（苍白球） , also substantia nigra（黑质） and subthalamus nucleus（丘脑底核） .

The balance between acetylcholine（乙酰胆碱） and dopamine（多巴胺） is important in motor control. Inhibitory neurotransmitter in BG is GABA.

Function: Regulate muscle tone, Regulate movements associated with goal-directed activities, Regulate automatic activities, Regulate postural adjustments during skilled movements, Regulate the relationship of required movement to the environment Regulate the learning of new movements.

Effects of damage: Disease of substantia nigra cause

Hypokinesia Increased muscle tone Increased resistance to passive movements Reduced range of movement (rigidity) Affectively expressionless.

Hyperkinesia result from excessive activity in dopaminergic nerve fibers cause involuntary movements.

Cerebellar hemispheres: control movement of ipsilateral side of body. Flocculonodular lobe（绒球小结叶） : modulate

equilibrium and orientation of head and eyes.

Anterior lobe（小脑前叶） : regulating posture, gait, and truncal tone.

Posterior lobe（小脑后叶） : coordinate skilled, voluntary muscle activity and muscle tone.

Reciprocal connections（交互连接） with cerebral cortex;

Auditory feedback and proprioceptive（本体感受） input from speech muscles, tendons and joints;

Reciprocal connections with brainstem components of the indirect activation pathways, and cooperative activity with the basal ganglia control circuit

Two important branches: Superior laryngeal nerve(SLN)喉上神经

internal and external laryngeal nerve Recurrent laryngeal nerve (RLN)喉返神经

Function: Innervation of striated muscles of the soft

palate, pharynx, and larynx 支配软腭咽喉的横纹肌 Sensation from soft palate, pharynx and

larynx 接受软腭、咽腔和喉腔的感觉

Unilateral LMN lesion单侧下运动神经元 : affect phonation

Bilateral LMN lesion双侧下运动神经元受损 : affect resonance, phonation, prosody and

clarity of articulation构音清晰度 , and swallowing吞咽 .

Produce weakness of soft palate, pharynx, and larynx.

Hypoadduction Paralysis Hyperadduction Ataxic Disorders Mixed Disorders

Myasthenia Gravis 重症肌无力 breathiness

Parkinsonism 帕金森症 monopitch and reduced loudness

Laryngeal paralysis 喉麻痹 breathiness

Unilateral paralysis 单侧声带麻痹 may see elevation of affected fold or

shortening of VF 可看到受损声带位置抬高或声带变短

Bilateral paralysis 双侧声带麻痹 limp flaccid appearance bowed and

short 麻痹部位松弛、弓形变短

Unilateral or bilateral 单侧或双侧 VF/s appear flaccid and floppy 声带变得无力、松软

Adduction position complete 完全中位 , paramedian 旁中位 , or

bilateral 外展位

Abduction position complete, paramedian, or bilateral

Spasmodic Dysphonia 痉挛性发音障碍 Essential tremor 特发性震颤 Huntington’s Chorea舞蹈症

laryngeal dystonia 喉肌张力障碍 Adductor (ADSD) 内收性

strained strangled quality 发音紧张 Spasms triggered by vowels 发元音易痉挛

Abductor (ABSD)外展性 Interspersed breathy spasms 全程气息音 Difficulty transitioning from voiced to

voiceless 从浊音难过渡到清音

Not considered a dystonia 不认为是肌张力异常

Regular involuntary movement 规律的不自主运动

Cerebellar ataxia小脑运动失调

Multiple sclerosis多发性硬化 Traumatic brain injury